Merge #355

355: Multi-core removal r=korken89 a=AfoHT

Dependent on https://github.com/rtic-rs/rtic-syntax/pull/27

With the same reasoning as ^^

For now the testing is done against my rtic-syntax/multiremove-branch, but before we merge it should corrected.

Co-authored-by: Henrik Tjäder <henrik@tjaders.com>

.github/workflows/build.yml

@@ -156,13 +156,6 @@ jobs:
           command: check
           args: --examples --target=${{ matrix.target }} --features __min_r1_43
 
-      - name: cargo check -p homogeneous
-        uses: actions-rs/cargo@v1
-        with:
-          use-cross: false
-          command: check
-          args: -p homogeneous --examples --target=${{ matrix.target }}
-
       # Use precompiled binutils
       - name: cargo install cargo-binutils
         uses: actions-rs/install@v0.1
@@ -481,57 +474,6 @@ jobs:
           command: test
           args: --test single
 
-  # Verify all multicore examples
-  checkmulticore:
-    name: checkmulticore
-    runs-on: ubuntu-20.04
-    strategy:
-      matrix:
-        target:
-          - x86_64-unknown-linux-gnu
-        toolchain:
-          - nightly
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Install Rust ${{ matrix.toolchain }} with x86_64-unknown-linux-gnu
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.toolchain }}
-          target: x86_64-unknown-linux-gnu
-          override: true
-      - name: Install Rust ${{ matrix.toolchain }} with thumbv7m-none-eabi
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.toolchain }}
-          target: thumbv7m-none-eabi
-          override: true
-      - name: Install Rust ${{ matrix.toolchain }} with thumbv6m-none-eabi
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.toolchain }}
-          target: thumbv6m-none-eabi
-          override: true
-      - uses: actions-rs/cargo@v1
-        with:
-          command: install
-          args: microamp-tools --version 0.1.0-alpha.3
-
-      - name: Check multi-core examples
-        run: |
-          cd heterogeneous
-          exs=(
-              smallest
-              x-init-2
-              x-init
-              x-schedule
-              x-spawn
-          )
-          for ex in ${exs[@]}; do
-              cargo-microamp --example=$ex --target thumbv7m-none-eabi,thumbv6m-none-eabi --check
-          done
-
   # Build documentation, check links
   docs:
     name: docs
@@ -661,7 +603,6 @@ jobs:
       - checkmacros
       - testv7
       - testv6
-      - checkmulticore
       - docs
       - mdbook
     # Only run this when pushing to master branch
@@ -765,7 +706,6 @@ jobs:
       - checkmacros
       - testv7
       - testv6
-      - checkmulticore
       - docs
       - mdbook
     runs-on: ubuntu-20.04
@@ -782,7 +722,6 @@ jobs:
       - checkmacros
       - testv7
       - testv6
-      - checkmulticore
       - docs
       - mdbook
     runs-on: ubuntu-20.04

Cargo.toml

@@ -77,8 +77,6 @@ version = "0.5.2"
 trybuild = "1"
 
 [features]
-heterogeneous = ["cortex-m-rtic-macros/heterogeneous", "microamp"]
-homogeneous = ["cortex-m-rtic-macros/homogeneous"]
 # used for testing this crate; do not use in applications
 __v7 =[]
 __min_r1_43 =[]
@@ -89,8 +87,6 @@ lto = true
 
 [workspace]
 members = [
-  "heterogeneous",
-  "homogeneous",
   "macros",
 ]
 

heterogeneous/Cargo.toml

@@ -1,18 +0,0 @@
-[package]
-authors = ["Jorge Aparicio <jorge@japaric.io>"]
-edition = "2018"
-name = "heterogeneous"
-# this crate is only used for testing
-publish = false
-version = "0.0.0-alpha.0"
-
-[dependencies]
-bare-metal = "0.2.4"
-
-[dependencies.cortex-m-rtic]
-path = ".."
-features = ["heterogeneous"]
-
-[dev-dependencies]
-panic-halt = "0.2.0"
-microamp = "0.1.0-alpha.1"

heterogeneous/README.md

@@ -1 +0,0 @@
-This directory contains *heterogeneous* multi-core compile pass tests.

heterogeneous/examples/smallest.rs

@@ -1,7 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = heterogeneous)]
-const APP: () = {};

heterogeneous/examples/x-init-2.rs

@@ -1,39 +0,0 @@
-//! [compile-pass] Cross initialization of late resources
-
-#![deny(unsafe_code)]
-#![deny(warnings)]
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = heterogeneous)]
-const APP: () = {
-    struct Resources {
-        // owned by core #1 but initialized by core #0
-        x: u32,
-
-        // owned by core #0 but initialized by core #1
-        y: u32,
-    }
-
-    #[init(core = 0, late = [x])]
-    fn a(_: a::Context) -> a::LateResources {
-        a::LateResources { x: 0 }
-    }
-
-    #[idle(core = 0, resources = [y])]
-    fn b(_: b::Context) -> ! {
-        loop {}
-    }
-
-    #[init(core = 1)]
-    fn c(_: c::Context) -> c::LateResources {
-        c::LateResources { y: 0 }
-    }
-
-    #[idle(core = 1, resources = [x])]
-    fn d(_: d::Context) -> ! {
-        loop {}
-    }
-};

heterogeneous/examples/x-init.rs

@@ -1,26 +0,0 @@
-//! [compile-pass] Split initialization of late resources
-
-#![deny(unsafe_code)]
-#![deny(warnings)]
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = heterogeneous)]
-const APP: () = {
-    struct Resources {
-        x: u32,
-        y: u32,
-    }
-
-    #[init(core = 0, late = [x])]
-    fn a(_: a::Context) -> a::LateResources {
-        a::LateResources { x: 0 }
-    }
-
-    #[init(core = 1)]
-    fn b(_: b::Context) -> b::LateResources {
-        b::LateResources { y: 0 }
-    }
-};

heterogeneous/examples/x-schedule.rs

@@ -1,36 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = heterogeneous, monotonic = heterogeneous::MT)]
-const APP: () = {
-    #[init(core = 0, spawn = [ping])]
-    fn init(c: init::Context) {
-        c.spawn.ping().ok();
-    }
-
-    #[task(core = 0, schedule = [ping])]
-    fn pong(c: pong::Context) {
-        c.schedule.ping(c.scheduled + 1_000_000).ok();
-    }
-
-    #[task(core = 1, schedule = [pong])]
-    fn ping(c: ping::Context) {
-        c.schedule.pong(c.scheduled + 1_000_000).ok();
-    }
-
-    extern "C" {
-        #[core = 0]
-        fn I0();
-
-        #[core = 0]
-        fn I1();
-
-        #[core = 1]
-        fn I0();
-
-        #[core = 1]
-        fn I1();
-    }
-};

heterogeneous/examples/x-spawn.rs

@@ -1,20 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = heterogeneous)]
-const APP: () = {
-    #[init(core = 0, spawn = [foo])]
-    fn init(c: init::Context) {
-        c.spawn.foo().ok();
-    }
-
-    #[task(core = 1)]
-    fn foo(_: foo::Context) {}
-
-    extern "C" {
-        #[core = 1]
-        fn I0();
-    }
-};

heterogeneous/src/lib.rs

@@ -1,99 +0,0 @@
-//! Fake multi-core PAC
-
-#![no_std]
-
-use core::{
-    cmp::Ordering,
-    ops::{Add, Sub},
-};
-
-use bare_metal::Nr;
-use rtic::{Fraction, Monotonic, MultiCore};
-
-// both cores have the exact same interrupts
-pub use Interrupt_0 as Interrupt_1;
-
-// Fake priority bits
-pub const NVIC_PRIO_BITS: u8 = 3;
-
-pub fn xpend(_core: u8, _interrupt: impl Nr) {}
-
-/// Fake monotonic timer
-pub struct MT;
-
-impl Monotonic for MT {
-    type Instant = Instant;
-
-    fn ratio() -> Fraction {
-        Fraction {
-            numerator: 1,
-            denominator: 1,
-        }
-    }
-
-    unsafe fn reset() {
-        (0xE0001004 as *mut u32).write_volatile(0)
-    }
-
-    fn now() -> Instant {
-        unsafe { Instant((0xE0001004 as *const u32).read_volatile() as i32) }
-    }
-
-    fn zero() -> Instant {
-        Instant(0)
-    }
-}
-
-impl MultiCore for MT {}
-
-#[derive(Clone, Copy, Eq, PartialEq)]
-pub struct Instant(i32);
-
-impl Add<u32> for Instant {
-    type Output = Instant;
-
-    fn add(self, rhs: u32) -> Self {
-        Instant(self.0.wrapping_add(rhs as i32))
-    }
-}
-
-impl Sub for Instant {
-    type Output = u32;
-
-    fn sub(self, rhs: Self) -> u32 {
-        self.0.checked_sub(rhs.0).unwrap() as u32
-    }
-}
-
-impl Ord for Instant {
-    fn cmp(&self, rhs: &Self) -> Ordering {
-        self.0.wrapping_sub(rhs.0).cmp(&0)
-    }
-}
-
-impl PartialOrd for Instant {
-    fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
-        Some(self.cmp(rhs))
-    }
-}
-
-// Fake interrupts
-#[allow(non_camel_case_types)]
-#[derive(Clone, Copy)]
-#[repr(u8)]
-pub enum Interrupt_0 {
-    I0 = 0,
-    I1 = 1,
-    I2 = 2,
-    I3 = 3,
-    I4 = 4,
-    I5 = 5,
-    I6 = 6,
-    I7 = 7,
-}
-
-unsafe impl Nr for Interrupt_0 {
-    fn nr(&self) -> u8 {
-        *self as u8
-    }
-}

homogeneous/Cargo.toml

@@ -1,17 +0,0 @@
-[package]
-authors = ["Jorge Aparicio <jorge@japaric.io>"]
-edition = "2018"
-name = "homogeneous"
-# this crate is only used for testing
-publish = false
-version = "0.0.0-alpha.0"
-
-[dependencies]
-bare-metal = "0.2.4"
-
-[dependencies.cortex-m-rtic]
-path = ".."
-features = ["homogeneous"]
-
-[dev-dependencies]
-panic-halt = "0.2.0"

homogeneous/README.md

@@ -1 +0,0 @@
-This directory contains *homogeneous* multi-core compile pass tests.

homogeneous/examples/smallest.rs

@@ -1,7 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = homogeneous)]
-const APP: () = {};

homogeneous/examples/x-init-2.rs

@@ -1,39 +0,0 @@
-//! [compile-pass] Cross initialization of late resources
-
-#![deny(unsafe_code)]
-#![deny(warnings)]
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = homogeneous)]
-const APP: () = {
-    struct Resources {
-        // owned by core #1 but initialized by core #0
-        x: u32,
-
-        // owned by core #0 but initialized by core #1
-        y: u32,
-    }
-
-    #[init(core = 0, late = [x])]
-    fn a(_: a::Context) -> a::LateResources {
-        a::LateResources { x: 0 }
-    }
-
-    #[idle(core = 0, resources = [y])]
-    fn b(_: b::Context) -> ! {
-        loop {}
-    }
-
-    #[init(core = 1)]
-    fn c(_: c::Context) -> c::LateResources {
-        c::LateResources { y: 0 }
-    }
-
-    #[idle(core = 1, resources = [x])]
-    fn d(_: d::Context) -> ! {
-        loop {}
-    }
-};

homogeneous/examples/x-init.rs

@@ -1,26 +0,0 @@
-//! [compile-pass] Split initialization of late resources
-
-#![deny(unsafe_code)]
-#![deny(warnings)]
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = homogeneous)]
-const APP: () = {
-    struct Resources {
-        x: u32,
-        y: u32,
-    }
-
-    #[init(core = 0, late = [x])]
-    fn a(_: a::Context) -> a::LateResources {
-        a::LateResources { x: 0 }
-    }
-
-    #[init(core = 1)]
-    fn b(_: b::Context) -> b::LateResources {
-        b::LateResources { y: 0 }
-    }
-};

homogeneous/examples/x-schedule.rs

@@ -1,36 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = homogeneous, monotonic = homogeneous::MT)]
-const APP: () = {
-    #[init(core = 0, spawn = [ping])]
-    fn init(c: init::Context) {
-        c.spawn.ping().ok();
-    }
-
-    #[task(core = 0, schedule = [ping])]
-    fn pong(c: pong::Context) {
-        c.schedule.ping(c.scheduled + 1_000_000).ok();
-    }
-
-    #[task(core = 1, schedule = [pong])]
-    fn ping(c: ping::Context) {
-        c.schedule.pong(c.scheduled + 1_000_000).ok();
-    }
-
-    extern "C" {
-        #[core = 0]
-        fn I0();
-
-        #[core = 0]
-        fn I1();
-
-        #[core = 1]
-        fn I0();
-
-        #[core = 1]
-        fn I1();
-    }
-};

homogeneous/examples/x-spawn.rs

@@ -1,20 +0,0 @@
-#![no_main]
-#![no_std]
-
-use panic_halt as _;
-
-#[rtic::app(cores = 2, device = homogeneous)]
-const APP: () = {
-    #[init(core = 0, spawn = [foo])]
-    fn init(c: init::Context) {
-        c.spawn.foo().ok();
-    }
-
-    #[task(core = 1)]
-    fn foo(_: foo::Context) {}
-
-    extern "C" {
-        #[core = 1]
-        fn I0();
-    }
-};

homogeneous/src/lib.rs

@@ -1,99 +0,0 @@
-//! Fake multi-core PAC
-
-#![no_std]
-
-use core::{
-    cmp::Ordering,
-    ops::{Add, Sub},
-};
-
-use bare_metal::Nr;
-use rtic::{Fraction, Monotonic, MultiCore};
-
-// both cores have the exact same interrupts
-pub use Interrupt_0 as Interrupt_1;
-
-// Fake priority bits
-pub const NVIC_PRIO_BITS: u8 = 3;
-
-pub fn xpend(_core: u8, _interrupt: impl Nr) {}
-
-/// Fake monotonic timer
-pub struct MT;
-
-impl Monotonic for MT {
-    type Instant = Instant;
-
-    fn ratio() -> Fraction {
-        Fraction {
-            numerator: 1,
-            denominator: 1,
-        }
-    }
-
-    unsafe fn reset() {
-        (0xE0001004 as *mut u32).write_volatile(0)
-    }
-
-    fn now() -> Instant {
-        unsafe { Instant((0xE0001004 as *const u32).read_volatile() as i32) }
-    }
-
-    fn zero() -> Instant {
-        Instant(0)
-    }
-}
-
-impl MultiCore for MT {}
-
-#[derive(Clone, Copy, Eq, PartialEq)]
-pub struct Instant(i32);
-
-impl Add<u32> for Instant {
-    type Output = Instant;
-
-    fn add(self, rhs: u32) -> Self {
-        Instant(self.0.wrapping_add(rhs as i32))
-    }
-}
-
-impl Sub for Instant {
-    type Output = u32;
-
-    fn sub(self, rhs: Self) -> u32 {
-        self.0.checked_sub(rhs.0).unwrap() as u32
-    }
-}
-
-impl Ord for Instant {
-    fn cmp(&self, rhs: &Self) -> Ordering {
-        self.0.wrapping_sub(rhs.0).cmp(&0)
-    }
-}
-
-impl PartialOrd for Instant {
-    fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
-        Some(self.cmp(rhs))
-    }
-}
-
-// Fake interrupts
-#[allow(non_camel_case_types)]
-#[derive(Clone, Copy)]
-#[repr(u8)]
-pub enum Interrupt_0 {
-    I0 = 0,
-    I1 = 1,
-    I2 = 2,
-    I3 = 3,
-    I4 = 4,
-    I5 = 5,
-    I6 = 6,
-    I7 = 7,
-}
-
-unsafe impl Nr for Interrupt_0 {
-    fn nr(&self) -> u8 {
-        *self as u8
-    }
-}

macros/Cargo.toml

@@ -21,8 +21,5 @@ proc-macro = true
 proc-macro2 = "1"
 quote = "1"
 syn = "1"
-rtic-syntax = "0.4.0"
+rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "master", version = "0.4.0" }
 
-[features]
-heterogeneous = []
-homogeneous = []

macros/src/analyze.rs

@@ -4,14 +4,14 @@ use std::collections::{BTreeMap, BTreeSet};
 use rtic_syntax::{
     analyze::{self, Priority},
     ast::App,
-    Core, P,
+    P,
 };
 use syn::Ident;
 
 /// Extend the upstream `Analysis` struct with our field
 pub struct Analysis {
     parent: P<analyze::Analysis>,
-    pub interrupts: BTreeMap<Core, BTreeMap<Priority, Ident>>,
+    pub interrupts: BTreeMap<Priority, Ident>,
 }
 
 impl ops::Deref for Analysis {
@@ -25,31 +25,20 @@ impl ops::Deref for Analysis {
 // Assign an `extern` interrupt to each priority level
 pub fn app(analysis: P<analyze::Analysis>, app: &App) -> P<Analysis> {
     let mut interrupts = BTreeMap::new();
-    for core in 0..app.args.cores {
     let priorities = app
         .software_tasks
         .values()
-            .filter_map(|task| {
+        .filter_map(|task| Some(task.args.priority))
-                if task.args.core == core {
+        .chain(analysis.timer_queues.first().map(|tq| tq.priority))
-                    Some(task.args.priority)
-                } else {
-                    None
-                }
-            })
-            .chain(analysis.timer_queues.get(&core).map(|tq| tq.priority))
         .collect::<BTreeSet<_>>();
 
     if !priorities.is_empty() {
-            interrupts.insert(
+        interrupts = priorities
-                core,
-                priorities
             .iter()
             .cloned()
             .rev()
-                    .zip(app.extern_interrupts[&core].keys().cloned())
+            .zip(app.extern_interrupts.keys().cloned())
-                    .collect(),
+            .collect();
-            );
-        }
     }
 
     P::new(Analysis {

macros/src/check.rs

@@ -10,7 +10,7 @@ use syn::{parse, Path};
 pub struct Extra<'a> {
     pub device: &'a Path,
     pub monotonic: Option<&'a Path>,
-    pub peripherals: Option<u8>,
+    pub peripherals: bool,
 }
 
 impl<'a> Extra<'a> {
@@ -20,35 +20,14 @@ impl<'a> Extra<'a> {
 }
 
 pub fn app<'a>(app: &'a App, analysis: &Analysis) -> parse::Result<Extra<'a>> {
-    if cfg!(feature = "homogeneous") {
+    // Check that all exceptions are valid; only exceptions with configurable priorities are
-        // this RTIC mode uses the same namespace for all cores so we need to check that the
-        // identifiers used for each core `#[init]` and `#[idle]` functions don't collide
-        let mut seen = HashSet::new();
-
-        for name in app
-            .inits
-            .values()
-            .map(|init| &init.name)
-            .chain(app.idles.values().map(|idle| &idle.name))
-        {
-            if seen.contains(name) {
-                return Err(parse::Error::new(
-                    name.span(),
-                    "this identifier is already being used by another core",
-                ));
-            } else {
-                seen.insert(name);
-            }
-        }
-    }
-
-    // check that all exceptions are valid; only exceptions with configurable priorities are
     // accepted
     for (name, task) in &app.hardware_tasks {
         let name_s = task.args.binds.to_string();
         match &*name_s {
             "SysTick" => {
-                if analysis.timer_queues.get(&task.args.core).is_some() {
+                // If the timer queue is used, then SysTick is unavailable
+                if !analysis.timer_queues.is_empty() {
                     return Err(parse::Error::new(
                         name.span(),
                         "this exception can't be used because it's being used by the runtime",
@@ -69,13 +48,9 @@ pub fn app<'a>(app: &'a App, analysis: &Analysis) -> parse::Result<Extra<'a>> {
         }
     }
 
-    // check that external (device-specific) interrupts are not named after known (Cortex-M)
+    // Check that external (device-specific) interrupts are not named after known (Cortex-M)
     // exceptions
-    for name in app
+    for name in app.extern_interrupts.keys() {
-        .extern_interrupts
-        .iter()
-        .flat_map(|(_, interrupts)| interrupts.keys())
-    {
         let name_s = name.to_string();
 
         match &*name_s {
@@ -91,52 +66,38 @@ pub fn app<'a>(app: &'a App, analysis: &Analysis) -> parse::Result<Extra<'a>> {
         }
     }
 
-    // check that there are enough external interrupts to dispatch the software tasks and the timer
+    // Check that there are enough external interrupts to dispatch the software tasks and the timer
     // queue handler
-    for core in 0..app.args.cores {
     let mut first = None;
     let priorities = app
         .software_tasks
         .iter()
         .filter_map(|(name, task)| {
-                if task.args.core == core {
             first = Some(name);
             Some(task.args.priority)
-                } else {
-                    None
-                }
         })
-            .chain(analysis.timer_queues.get(&core).map(|tq| tq.priority))
+        .chain(analysis.timer_queues.first().map(|tq| tq.priority))
         .collect::<HashSet<_>>();
 
     let need = priorities.len();
-        let given = app
+    let given = app.extern_interrupts.len();
-            .extern_interrupts
-            .get(&core)
-            .map(|ei| ei.len())
-            .unwrap_or(0);
     if need > given {
-            let s = if app.args.cores == 1 {
+        let s = {
             format!(
                 "not enough `extern` interrupts to dispatch \
                     all software tasks (need: {}; given: {})",
                 need, given
             )
-            } else {
-                format!(
-                    "not enough `extern` interrupts to dispatch \
-                     all software tasks on this core (need: {}; given: {})",
-                    need, given
-                )
         };
 
+        // If not enough tasks and first still is None, may cause
+        // "custom attribute panicked" due to unwrap on None
         return Err(parse::Error::new(first.unwrap().span(), &s));
     }
-    }
 
     let mut device = None;
     let mut monotonic = None;
-    let mut peripherals = None;
+    let mut peripherals = false;
 
     for (k, v) in &app.args.custom {
         let ks = k.to_string();
@@ -165,34 +126,11 @@ pub fn app<'a>(app: &'a App, analysis: &Analysis) -> parse::Result<Extra<'a>> {
             },
 
             "peripherals" => match v {
-                CustomArg::Bool(x) if app.args.cores == 1 => {
+                CustomArg::Bool(x) => peripherals = if *x { true } else { false },
-                    peripherals = if *x { Some(0) } else { None }
-                }
-
-                CustomArg::UInt(s) if app.args.cores != 1 => {
-                    let x = s.parse::<u8>().ok();
-                    peripherals = if x.is_some() && x.unwrap() < app.args.cores {
-                        Some(x.unwrap())
-                    } else {
-                        return Err(parse::Error::new(
-                            k.span(),
-                            &format!(
-                                "unexpected argument value; \
-                                 this should be an integer in the range 0..={}",
-                                app.args.cores
-                            ),
-                        ));
-                    }
-                }
-
                 _ => {
                     return Err(parse::Error::new(
                         k.span(),
-                        if app.args.cores == 1 {
+                        "unexpected argument value; this should be a boolean",
-                            "unexpected argument value; this should be a boolean"
-                        } else {
-                            "unexpected argument value; this should be an integer"
-                        },
                     ));
                 }
             },
@@ -203,7 +141,7 @@ pub fn app<'a>(app: &'a App, analysis: &Analysis) -> parse::Result<Extra<'a>> {
         }
     }
 
-    if !analysis.timer_queues.is_empty() && monotonic.is_none() {
+    if !&analysis.timer_queues.is_empty() && monotonic.is_none() {
         return Err(parse::Error::new(
             Span::call_site(),
             "a `monotonic` timer must be specified to use the `schedule` API",

macros/src/codegen.rs

@@ -30,20 +30,16 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
     let mut root = vec![];
     let mut user = vec![];
 
-    // generate a `main` function for each core
+    // Generate the `main` function
-    for core in 0..app.args.cores {
+    let assertion_stmts = assertions::codegen(analysis);
-        let assertion_stmts = assertions::codegen(core, analysis, extra);
 
-        let (const_app_pre_init, pre_init_stmts) = pre_init::codegen(core, &app, analysis, extra);
+    let pre_init_stmts = pre_init::codegen(&app, analysis, extra);
 
-        let (const_app_init, root_init, user_init, call_init) =
+    let (const_app_init, root_init, user_init, call_init) = init::codegen(app, analysis, extra);
-            init::codegen(core, app, analysis, extra);
 
-        let (const_app_post_init, post_init_stmts) =
+    let post_init_stmts = post_init::codegen(&app, analysis);
-            post_init::codegen(core, &app, analysis, extra);
 
-        let (const_app_idle, root_idle, user_idle, call_idle) =
+    let (const_app_idle, root_idle, user_idle, call_idle) = idle::codegen(app, analysis, extra);
-            idle::codegen(core, app, analysis, extra);
 
     user.push(quote!(
         #user_init
@@ -58,22 +54,14 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
     ));
 
     const_app.push(quote!(
-            #(#const_app_pre_init)*
-
         #const_app_init
 
-            #(#const_app_post_init)*
-
         #const_app_idle
     ));
 
-        let cfg_core = util::cfg_core(core, app.args.cores);
+    let main = util::suffixed("main");
-        let main = util::suffixed("main", core);
-        let section = util::link_section("text", core);
     mains.push(quote!(
         #[no_mangle]
-            #section
-            #cfg_core
         unsafe extern "C" fn #main() -> ! {
             let _TODO: () = ();
 
@@ -88,7 +76,6 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
             #call_idle
         }
     ));
-    }
 
     let (const_app_resources, mod_resources) = resources::codegen(app, analysis, extra);
 
@@ -106,18 +93,6 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
 
     let const_app_schedule = schedule::codegen(app, extra);
 
-    let cores = app.args.cores.to_string();
-    let cfg_core = quote!(#[cfg(core = #cores)]);
-    let msg = format!(
-        "specified {} core{} but tried to compile for more than {0} core{1}",
-        app.args.cores,
-        if app.args.cores > 1 { "s" } else { "" }
-    );
-    let check_excess_cores = quote!(
-        #cfg_core
-        compile_error!(#msg);
-    );
-
     let name = &app.name;
     let device = extra.device;
     quote!(
@@ -136,13 +111,11 @@ pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
         #(#root_software_tasks)*
 
         /// Implementation details
-        // the user can't access the items within this `const` item
+        // The user can't access the items within this `const` item
         const #name: () = {
             /// Always include the device crate which contains the vector table
             use #device as _;
 
-            #check_excess_cores
-
             #(#const_app)*
 
             #(#const_app_resources)*

macros/src/codegen/assertions.rs

@@ -1,33 +1,19 @@
 use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
 
-use crate::{analyze::Analysis, check::Extra};
+use crate::analyze::Analysis;
 
 /// Generates compile-time assertions that check that types implement the `Send` / `Sync` traits
-pub fn codegen(core: u8, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream2> {
+pub fn codegen(analysis: &Analysis) -> Vec<TokenStream2> {
     let mut stmts = vec![];
 
-    // we don't generate *all* assertions on all cores because the user could conditionally import a
+    for ty in &analysis.send_types {
-    // type only on some core (e.g. `#[cfg(core = "0")] use some::Type;`)
-
-    if let Some(types) = analysis.send_types.get(&core) {
-        for ty in types {
         stmts.push(quote!(rtic::export::assert_send::<#ty>();));
     }
-    }
 
-    if let Some(types) = analysis.sync_types.get(&core) {
+    for ty in &analysis.sync_types {
-        for ty in types {
         stmts.push(quote!(rtic::export::assert_sync::<#ty>();));
     }
-    }
-
-    // if the `schedule` API is used in more than one core then we need to check that the
-    // `monotonic` timer can be used in multi-core context
-    if analysis.timer_queues.len() > 1 && analysis.timer_queues.contains_key(&core) {
-        let monotonic = extra.monotonic();
-        stmts.push(quote!(rtic::export::assert_multicore::<#monotonic>();));
-    }
 
     stmts
 }

macros/src/codegen/dispatchers.rs

@@ -8,15 +8,11 @@ use crate::{analyze::Analysis, check::Extra, codegen::util};
 pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream2> {
     let mut items = vec![];
 
-    for (&receiver, dispatchers) in &analysis.channels {
+    let interrupts = &analysis.interrupts;
-        let interrupts = &analysis.interrupts[&receiver];
 
-        for (&level, channels) in dispatchers {
+    for (&level, channel) in &analysis.channels {
         let mut stmts = vec![];
 
-            for (&sender, channel) in channels {
-                let cfg_sender = util::cfg_core(sender, app.args.cores);
-
         let variants = channel
             .tasks
             .iter()
@@ -31,10 +27,10 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             .collect::<Vec<_>>();
 
         let doc = format!(
-                    "Software tasks spawned from core #{} to be dispatched at priority level {} by core #{}",
+            "Software tasks to be dispatched at priority level {}",
-                    sender, level, receiver,
+            level,
         );
-                let t = util::spawn_t_ident(receiver, level, sender);
+        let t = util::spawn_t_ident(level);
         items.push(quote!(
             #[allow(non_camel_case_types)]
             #[derive(Clone, Copy)]
@@ -45,47 +41,27 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
         ));
 
         let n = util::capacity_typenum(channel.capacity, true);
-                let rq = util::rq_ident(receiver, level, sender);
+        let rq = util::rq_ident(level);
-                let (rq_attr, rq_ty, rq_expr, section) = if sender == receiver {
+        let (rq_ty, rq_expr) = {
             (
-                        cfg_sender.clone(),
                 quote!(rtic::export::SCRQ<#t, #n>),
                 quote!(rtic::export::Queue(unsafe {
                     rtic::export::iQueue::u8_sc()
                 })),
-                        util::link_section("bss", sender),
-                    )
-                } else {
-                    let shared = if cfg!(feature = "heterogeneous") {
-                        Some(quote!(#[rtic::export::shared]))
-                    } else {
-                        None
-                    };
-
-                    (
-                        shared,
-                        quote!(rtic::export::MCRQ<#t, #n>),
-                        quote!(rtic::export::Queue(rtic::export::iQueue::u8())),
-                        None,
             )
         };
 
         let doc = format!(
-                    "Queue of tasks sent by core #{} ready to be dispatched by core #{} at priority level {}",
+            "Queue of tasks ready to be dispatched at priority level {}",
-                    sender,
-                    receiver,
             level
         );
         items.push(quote!(
             #[doc = #doc]
-                    #rq_attr
-                    #section
             static mut #rq: #rq_ty = #rq_expr;
         ));
 
         if let Some(ceiling) = channel.ceiling {
             items.push(quote!(
-                        #cfg_sender
                 struct #rq<'a> {
                     priority: &'a rtic::export::Priority,
                 }
@@ -94,7 +70,6 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             items.push(util::impl_mutex(
                 extra,
                 &[],
-                        cfg_sender.as_ref(),
                 false,
                 &rq,
                 rq_ty,
@@ -109,12 +84,12 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             .map(|name| {
                 let task = &app.software_tasks[name];
                 let cfgs = &task.cfgs;
-                        let fq = util::fq_ident(name, sender);
+                let fq = util::fq_ident(name);
-                        let inputs = util::inputs_ident(name, sender);
+                let inputs = util::inputs_ident(name);
                 let (_, tupled, pats, _) = util::regroup_inputs(&task.inputs);
 
-                        let (let_instant, instant) = if app.uses_schedule(receiver) {
+                let (let_instant, instant) = if app.uses_schedule() {
-                            let instants = util::instants_ident(name, sender);
+                    let instants = util::instants_ident(name);
 
                     (
                         quote!(
@@ -158,21 +133,13 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
                 }
             }
         ));
-            }
 
-            let doc = format!(
+        let doc = format!("Interrupt handler to dispatch tasks at priority {}", level);
-                "Interrupt handler used by core #{} to dispatch tasks at priority {}",
+        let interrupt = util::suffixed(&interrupts[&level].to_string());
-                receiver, level
-            );
-            let cfg_receiver = util::cfg_core(receiver, app.args.cores);
-            let section = util::link_section("text", receiver);
-            let interrupt = util::suffixed(&interrupts[&level].to_string(), receiver);
         items.push(quote!(
             #[allow(non_snake_case)]
             #[doc = #doc]
             #[no_mangle]
-                #cfg_receiver
-                #section
             unsafe fn #interrupt() {
                 /// The priority of this interrupt handler
                 const PRIORITY: u8 = #level;
@@ -183,7 +150,6 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             }
         ));
     }
-    }
 
     items
 }

macros/src/codegen/hardware_tasks.rs

@@ -5,7 +5,7 @@ use rtic_syntax::{ast::App, Context};
 use crate::{
     analyze::Analysis,
     check::Extra,
-    codegen::{locals, module, resources_struct, util},
+    codegen::{locals, module, resources_struct},
 };
 
 /// Generate support code for hardware tasks (`#[exception]`s and `#[interrupt]`s)
@@ -29,10 +29,7 @@ pub fn codegen(
     let mut user_tasks = vec![];
 
     for (name, task) in &app.hardware_tasks {
-        let core = task.args.core;
+        let (let_instant, instant) = if app.uses_schedule() {
-        let cfg_core = util::cfg_core(core, app.args.cores);
-
-        let (let_instant, instant) = if app.uses_schedule(core) {
             let m = extra.monotonic();
 
             (
@@ -49,19 +46,12 @@ pub fn codegen(
             quote!(#name::Locals::new(),)
         };
 
-        let symbol = if cfg!(feature = "homogeneous") {
+        let symbol = task.args.binds.clone();
-            util::suffixed(&task.args.binds.to_string(), core)
-        } else {
-            task.args.binds.clone()
-        };
         let priority = task.args.priority;
 
-        let section = util::link_section("text", core);
         const_app.push(quote!(
             #[allow(non_snake_case)]
             #[no_mangle]
-            #section
-            #cfg_core
             unsafe fn #symbol() {
                 const PRIORITY: u8 = #priority;
 
@@ -103,8 +93,7 @@ pub fn codegen(
         // `${task}Locals`
         let mut locals_pat = None;
         if !task.locals.is_empty() {
-            let (struct_, pat) =
+            let (struct_, pat) = locals::codegen(Context::HardwareTask(name), &task.locals, app);
-                locals::codegen(Context::HardwareTask(name), &task.locals, core, app);
 
             root.push(struct_);
             locals_pat = Some(pat);
@@ -113,13 +102,10 @@ pub fn codegen(
         let attrs = &task.attrs;
         let context = &task.context;
         let stmts = &task.stmts;
-        let section = util::link_section("text", core);
-        // XXX shouldn't this have a cfg_core?
         let locals_pat = locals_pat.iter();
         user_tasks.push(quote!(
             #(#attrs)*
             #[allow(non_snake_case)]
-            #section
             fn #name(#(#locals_pat,)* #context: #name::Context) {
                 use rtic::Mutex as _;
 

macros/src/codegen/idle.rs

@@ -5,12 +5,11 @@ use rtic_syntax::{ast::App, Context};
 use crate::{
     analyze::Analysis,
     check::Extra,
-    codegen::{locals, module, resources_struct, util},
+    codegen::{locals, module, resources_struct},
 };
 
 /// Generates support code for `#[idle]` functions
 pub fn codegen(
-    core: u8,
     app: &App,
     analysis: &Analysis,
     extra: &Extra,
@@ -27,7 +26,8 @@ pub fn codegen(
     // call_idle
     TokenStream2,
 ) {
-    if let Some(idle) = app.idles.get(&core) {
+    if app.idles.len() > 0 {
+        let idle = &app.idles.first().unwrap();
         let mut needs_lt = false;
         let mut const_app = None;
         let mut root_idle = vec![];
@@ -36,7 +36,7 @@ pub fn codegen(
 
         if !idle.args.resources.is_empty() {
             let (item, constructor) =
-                resources_struct::codegen(Context::Idle(core), 0, &mut needs_lt, app, analysis);
+                resources_struct::codegen(Context::Idle, 0, &mut needs_lt, app, analysis);
 
             root_idle.push(item);
             const_app = Some(constructor);
@@ -44,26 +44,22 @@ pub fn codegen(
 
         let name = &idle.name;
         if !idle.locals.is_empty() {
-            let (locals, pat) = locals::codegen(Context::Idle(core), &idle.locals, core, app);
+            let (locals, pat) = locals::codegen(Context::Idle, &idle.locals, app);
 
             locals_new = Some(quote!(#name::Locals::new()));
             locals_pat = Some(pat);
             root_idle.push(locals);
         }
 
-        root_idle.push(module::codegen(Context::Idle(core), needs_lt, app, extra));
+        root_idle.push(module::codegen(Context::Idle, needs_lt, app, extra));
 
-        let cfg_core = util::cfg_core(core, app.args.cores);
         let attrs = &idle.attrs;
         let context = &idle.context;
         let stmts = &idle.stmts;
-        let section = util::link_section("text", core);
         let locals_pat = locals_pat.iter();
         let user_idle = Some(quote!(
             #(#attrs)*
             #[allow(non_snake_case)]
-            #cfg_core
-            #section
             fn #name(#(#locals_pat,)* #context: #name::Context) -> ! {
                 use rtic::Mutex as _;
 

macros/src/codegen/init.rs

@@ -10,7 +10,6 @@ use crate::{
 
 /// Generates support code for `#[init]` functions
 pub fn codegen(
-    core: u8,
     app: &App,
     analysis: &Analysis,
     extra: &Extra,
@@ -28,8 +27,8 @@ pub fn codegen(
     // call_init -- the call to the user `#[init]` if there's one
     Option<TokenStream2>,
 ) {
-    if let Some(init) = app.inits.get(&core) {
+    if app.inits.len() > 0 {
-        let cfg_core = util::cfg_core(core, app.args.cores);
+        let init = &app.inits.first().unwrap();
         let mut needs_lt = false;
         let name = &init.name;
 
@@ -38,11 +37,9 @@ pub fn codegen(
         let ret = {
             let late_fields = analysis
                 .late_resources
-                .get(&core)
-                .map(|resources| {
-                    resources
                 .iter()
-                        .map(|name| {
+                .flat_map(|resources| {
+                    resources.iter().map(|name| {
                         let ty = &app.late_resources[name].ty;
                         let cfgs = &app.late_resources[name].cfgs;
 
@@ -51,16 +48,14 @@ pub fn codegen(
                         pub #name: #ty
                         )
                     })
-                        .collect::<Vec<_>>()
                 })
-                .unwrap_or(vec![]);
+                .collect::<Vec<_>>();
 
             if !late_fields.is_empty() {
                 let late_resources = util::late_resources_ident(&name);
 
                 root_init.push(quote!(
                     /// Resources initialized at runtime
-                    #cfg_core
                     #[allow(non_snake_case)]
                     pub struct #late_resources {
                         #(#late_fields),*
@@ -76,7 +71,7 @@ pub fn codegen(
         let mut locals_pat = None;
         let mut locals_new = None;
         if !init.locals.is_empty() {
-            let (struct_, pat) = locals::codegen(Context::Init(core), &init.locals, core, app);
+            let (struct_, pat) = locals::codegen(Context::Init, &init.locals, app);
 
             locals_new = Some(quote!(#name::Locals::new()));
             locals_pat = Some(pat);
@@ -86,13 +81,10 @@ pub fn codegen(
         let context = &init.context;
         let attrs = &init.attrs;
         let stmts = &init.stmts;
-        let section = util::link_section("text", core);
         let locals_pat = locals_pat.iter();
         let user_init = Some(quote!(
             #(#attrs)*
-            #cfg_core
             #[allow(non_snake_case)]
-            #section
             fn #name(#(#locals_pat,)* #context: #name::Context) #ret {
                 #(#stmts)*
             }
@@ -101,7 +93,7 @@ pub fn codegen(
         let mut const_app = None;
         if !init.args.resources.is_empty() {
             let (item, constructor) =
-                resources_struct::codegen(Context::Init(core), 0, &mut needs_lt, app, analysis);
+                resources_struct::codegen(Context::Init, 0, &mut needs_lt, app, analysis);
 
             root_init.push(item);
             const_app = Some(constructor);
@@ -112,7 +104,7 @@ pub fn codegen(
             quote!(let late = crate::#name(#(#locals_new,)* #name::Context::new(core.into()));),
         );
 
-        root_init.push(module::codegen(Context::Init(core), needs_lt, app, extra));
+        root_init.push(module::codegen(Context::Init, needs_lt, app, extra));
 
         (const_app, root_init, user_init, call_init)
     } else {

macros/src/codegen/locals.rs

@@ -2,7 +2,7 @@ use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
 use rtic_syntax::{
     ast::{App, Local},
-    Context, Core, Map,
+    Context, Map,
 };
 
 use crate::codegen::util;
@@ -10,7 +10,6 @@ use crate::codegen::util;
 pub fn codegen(
     ctxt: Context,
     locals: &Map<Local>,
-    core: Core,
     app: &App,
 ) -> (
     // locals
@@ -42,11 +41,6 @@ pub fn codegen(
         let cfgs = &local.cfgs;
         has_cfgs |= !cfgs.is_empty();
 
-        let section = if local.shared && cfg!(feature = "heterogeneous") {
-            Some(quote!(#[rtic::export::shared]))
-        } else {
-            util::link_section("data", core)
-        };
         let expr = &local.expr;
         let ty = &local.ty;
         fields.push(quote!(
@@ -55,7 +49,6 @@ pub fn codegen(
         ));
         items.push(quote!(
             #(#cfgs)*
-            #section
             static mut #name: #ty = #expr
         ));
         values.push(quote!(

macros/src/codegen/module.rs

@@ -11,12 +11,11 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
 
     let name = ctxt.ident(app);
 
-    let core = ctxt.core(app);
     let mut needs_instant = false;
     let mut lt = None;
     match ctxt {
-        Context::Init(core) => {
+        Context::Init => {
-            if app.uses_schedule(core) {
+            if app.uses_schedule() {
                 let m = extra.monotonic();
 
                 fields.push(quote!(
@@ -37,7 +36,7 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
                 ));
             }
 
-            if extra.peripherals == Some(core) {
+            if extra.peripherals {
                 let device = extra.device;
 
                 fields.push(quote!(
@@ -51,10 +50,10 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
             values.push(quote!(core));
         }
 
-        Context::Idle(..) => {}
+        Context::Idle => {}
 
         Context::HardwareTask(..) => {
-            if app.uses_schedule(core) {
+            if app.uses_schedule() {
                 let m = extra.monotonic();
 
                 fields.push(quote!(
@@ -69,7 +68,7 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
         }
 
         Context::SoftwareTask(..) => {
-            if app.uses_schedule(core) {
+            if app.uses_schedule() {
                 let m = extra.monotonic();
 
                 fields.push(quote!(
@@ -205,7 +204,7 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
 
                 values.push(quote!(spawn: Spawn { priority }));
             } else {
-                let instant_field = if app.uses_schedule(core) {
+                let instant_field = if app.uses_schedule() {
                     let m = extra.monotonic();
 
                     needs_instant = true;
@@ -252,8 +251,8 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
         }
     }
 
-    if let Context::Init(core) = ctxt {
+    if let Context::Init = ctxt {
-        let init = &app.inits[&core];
+        let init = &app.inits.first().unwrap();
         if init.returns_late_resources {
             let late_resources = util::late_resources_ident(&init.name);
 
@@ -265,14 +264,14 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
     }
 
     let doc = match ctxt {
-        Context::Idle(_) => "Idle loop",
+        Context::Idle => "Idle loop",
-        Context::Init(_) => "Initialization function",
+        Context::Init => "Initialization function",
         Context::HardwareTask(_) => "Hardware task",
         Context::SoftwareTask(_) => "Software task",
     };
 
     let core = if ctxt.is_init() {
-        if app.uses_schedule(core) {
+        if app.uses_schedule() {
             Some(quote!(core: rtic::Peripherals,))
         } else {
             Some(quote!(core: rtic::export::Peripherals,))
@@ -312,12 +311,9 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
     ));
 
     if !items.is_empty() {
-        let cfg_core = util::cfg_core(ctxt.core(app), app.args.cores);
-
         quote!(
             #[allow(non_snake_case)]
             #[doc = #doc]
-            #cfg_core
             pub mod #name {
                 #(#items)*
             }

macros/src/codegen/post_init.rs

@@ -2,22 +2,17 @@ use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
 use rtic_syntax::ast::App;
 
-use crate::{analyze::Analysis, check::Extra, codegen::util};
+use crate::analyze::Analysis;
 
 /// Generates code that runs after `#[init]` returns
-pub fn codegen(
+pub fn codegen(app: &App, analysis: &Analysis) -> Vec<TokenStream2> {
-    core: u8,
-    app: &App,
-    analysis: &Analysis,
-    extra: &Extra,
-) -> (Vec<TokenStream2>, Vec<TokenStream2>) {
-    let mut const_app = vec![];
     let mut stmts = vec![];
 
-    // initialize late resources
+    // Initialize late resources
-    if let Some(late_resources) = analysis.late_resources.get(&core) {
+    if analysis.late_resources.len() > 0 {
-        for name in late_resources {
+        // BTreeSet wrapped in a vector
-            // if it's live
+        for name in analysis.late_resources.first().unwrap() {
+            // If it's live
             let cfgs = app.late_resources[name].cfgs.clone();
             if analysis.locations.get(name).is_some() {
                 // Need to also include the cfgs
@@ -29,134 +24,8 @@ pub fn codegen(
         }
     }
 
-    if analysis.timer_queues.is_empty() {
+    // Enable the interrupts -- this completes the `init`-ialization phase
-        // cross-initialization barriers -- notify *other* cores that their resources have been
-        // initialized
-        for (user, initializers) in &analysis.initialization_barriers {
-            if !initializers.contains(&core) {
-                continue;
-            }
-
-            let ib = util::init_barrier(*user);
-            let shared = if cfg!(feature = "heterogeneous") {
-                Some(quote!(
-                    #[rtic::export::shared]
-                ))
-            } else {
-                None
-            };
-
-            const_app.push(quote!(
-                #shared
-                static #ib: rtic::export::Barrier = rtic::export::Barrier::new();
-            ));
-
-            stmts.push(quote!(
-                #ib.release();
-            ));
-        }
-
-        // then wait until the other cores have initialized *our* resources
-        if analysis.initialization_barriers.contains_key(&core) {
-            let ib = util::init_barrier(core);
-
-            stmts.push(quote!(
-                #ib.wait();
-            ));
-        }
-
-        // cross-spawn barriers: wait until other cores are ready to receive messages
-        for (&receiver, senders) in &analysis.spawn_barriers {
-            if senders.get(&core) == Some(&false) {
-                let sb = util::spawn_barrier(receiver);
-
-                stmts.push(quote!(
-                    #sb.wait();
-                ));
-            }
-        }
-    } else {
-        // if the `schedule` API is used then we'll synchronize all cores to leave the
-        // `init`-ialization phase at the same time. In this case the rendezvous barrier makes the
-        // cross-initialization and spawn barriers unnecessary
-
-        let m = extra.monotonic();
-
-        if analysis.timer_queues.len() == 1 {
-            // reset the monotonic timer / counter
-            stmts.push(quote!(
-                <#m as rtic::Monotonic>::reset();
-            ));
-        } else {
-            // in the multi-core case we need a rendezvous (RV) barrier between *all* the cores that
-            // use the `schedule` API; otherwise one of the cores could observe the before-reset
-            // value of the monotonic counter
-            // (this may be easier to implement with `AtomicU8.fetch_sub` but that API is not
-            // available on ARMv6-M)
-
-            // this core will reset the monotonic counter
-            const FIRST: u8 = 0;
-
-            if core == FIRST {
-                for &i in analysis.timer_queues.keys() {
-                    let rv = util::rendezvous_ident(i);
-                    let shared = if cfg!(feature = "heterogeneous") {
-                        Some(quote!(
-                            #[rtic::export::shared]
-                        ))
-                    } else {
-                        None
-                    };
-
-                    const_app.push(quote!(
-                        #shared
-                        static #rv: rtic::export::Barrier = rtic::export::Barrier::new();
-                    ));
-
-                    // wait until all the other cores have reached the RV point
-                    if i != FIRST {
-                        stmts.push(quote!(
-                            #rv.wait();
-                        ));
-                    }
-                }
-
-                let rv = util::rendezvous_ident(core);
-                stmts.push(quote!(
-                    // the compiler fences are used to prevent `reset` from being re-ordering wrt to
-                    // the atomic operations -- we don't know if `reset` contains load or store
-                    // operations
-
-                    core::sync::atomic::compiler_fence(core::sync::atomic::Ordering::SeqCst);
-
-                    // reset the counter
-                    <#m as rtic::Monotonic>::reset();
-
-                    core::sync::atomic::compiler_fence(core::sync::atomic::Ordering::SeqCst);
-
-                    // now unblock all the other cores
-                    #rv.release();
-                ));
-            } else {
-                let rv = util::rendezvous_ident(core);
-
-                // let the first core know that we have reached the RV point
-                stmts.push(quote!(
-                    #rv.release();
-                ));
-
-                let rv = util::rendezvous_ident(FIRST);
-
-                // wait until the first core has reset the monotonic timer
-                stmts.push(quote!(
-                    #rv.wait();
-                ));
-            }
-        }
-    }
-
-    // enable the interrupts -- this completes the `init`-ialization phase
     stmts.push(quote!(rtic::export::interrupt::enable();));
 
-    (const_app, stmts)
+    stmts
 }

macros/src/codegen/pre_init.rs

@@ -5,75 +5,52 @@ use rtic_syntax::ast::App;
 use crate::{analyze::Analysis, check::Extra, codegen::util};
 
 /// Generates code that runs before `#[init]`
-pub fn codegen(
+pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream2> {
-    core: u8,
-    app: &App,
-    analysis: &Analysis,
-    extra: &Extra,
-) -> (
-    // `const_app_pre_init` -- `static` variables for barriers
-    Vec<TokenStream2>,
-    // `pre_init_stmts`
-    Vec<TokenStream2>,
-) {
-    let mut const_app = vec![];
     let mut stmts = vec![];
 
-    // disable interrupts -- `init` must run with interrupts disabled
+    // Disable interrupts -- `init` must run with interrupts disabled
     stmts.push(quote!(rtic::export::interrupt::disable();));
 
-    // populate this core `FreeQueue`s
+    // Populate the FreeQueue
-    for (name, senders) in &analysis.free_queues {
+    for fq in &analysis.free_queues {
+        // Get the task name
+        let name = fq.0;
         let task = &app.software_tasks[name];
         let cap = task.args.capacity;
 
-        for &sender in senders.keys() {
+        let fq_ident = util::fq_ident(name);
-            if sender == core {
-                let fq = util::fq_ident(name, sender);
 
         stmts.push(quote!(
-                    (0..#cap).for_each(|i| #fq.enqueue_unchecked(i));
+            (0..#cap).for_each(|i| #fq_ident.enqueue_unchecked(i));
         ));
     }
-        }
-    }
 
-    if app.args.cores == 1 {
     stmts.push(quote!(
         // To set the variable in cortex_m so the peripherals cannot be taken multiple times
         let mut core: rtic::export::Peripherals = rtic::export::Peripherals::steal().into();
     ));
-    } else {
-        stmts.push(quote!(
-            // NOTE(transmute) to avoid debug_assertion in multi-core mode
-            // (This code will go away when we drop multi-core mode)
-            let mut core: rtic::export::Peripherals = core::mem::transmute(());
-        ));
-    }
 
     let device = extra.device;
     let nvic_prio_bits = quote!(#device::NVIC_PRIO_BITS);
 
-    // unmask interrupts and set their priorities
+    // Unmask interrupts and set their priorities
     for (&priority, name) in analysis
         .interrupts
-        .get(&core)
         .iter()
-        .flat_map(|interrupts| *interrupts)
         .chain(app.hardware_tasks.values().flat_map(|task| {
             if !util::is_exception(&task.args.binds) {
                 Some((&task.args.priority, &task.args.binds))
             } else {
-                // we do exceptions in another pass
+                // We do exceptions in another pass
                 None
             }
         }))
     {
-        // compile time assert that this priority is supported by the device
+        // Compile time assert that this priority is supported by the device
         stmts.push(quote!(let _ = [(); ((1 << #nvic_prio_bits) - #priority as usize)];));
 
         // NOTE this also checks that the interrupt exists in the `Interrupt` enumeration
-        let interrupt = util::interrupt_ident(core, app.args.cores);
+        let interrupt = util::interrupt_ident();
         stmts.push(quote!(
             core.NVIC.set_priority(
                 #device::#interrupt::#name,
@@ -86,30 +63,7 @@ pub fn codegen(
         stmts.push(quote!(rtic::export::NVIC::unmask(#device::#interrupt::#name);));
     }
 
-    // cross-spawn barriers: now that priorities have been set and the interrupts have been unmasked
+    // Set exception priorities
-    // we are ready to receive messages from *other* cores
-    if analysis.spawn_barriers.contains_key(&core) {
-        let sb = util::spawn_barrier(core);
-        let shared = if cfg!(feature = "heterogeneous") {
-            Some(quote!(
-                #[rtic::export::shared]
-            ))
-        } else {
-            None
-        };
-
-        const_app.push(quote!(
-            #shared
-            static #sb: rtic::export::Barrier = rtic::export::Barrier::new();
-        ));
-
-        // unblock cores that may send us a message
-        stmts.push(quote!(
-            #sb.release();
-        ));
-    }
-
-    // set exception priorities
     for (name, priority) in app.hardware_tasks.values().filter_map(|task| {
         if util::is_exception(&task.args.binds) {
             Some((&task.args.binds, task.args.priority))
@@ -117,7 +71,7 @@ pub fn codegen(
             None
         }
     }) {
-        // compile time assert that this priority is supported by the device
+        // Compile time assert that this priority is supported by the device
         stmts.push(quote!(let _ = [(); ((1 << #nvic_prio_bits) - #priority as usize)];));
 
         stmts.push(quote!(core.SCB.set_priority(
@@ -126,11 +80,11 @@ pub fn codegen(
         );));
     }
 
-    // initialize the SysTick
+    // Initialize the SysTick if there exist a TimerQueue
-    if let Some(tq) = analysis.timer_queues.get(&core) {
+    if let Some(tq) = analysis.timer_queues.first() {
         let priority = tq.priority;
 
-        // compile time assert that this priority is supported by the device
+        // Compile time assert that this priority is supported by the device
         stmts.push(quote!(let _ = [(); ((1 << #nvic_prio_bits) - #priority as usize)];));
 
         stmts.push(quote!(core.SCB.set_priority(
@@ -145,23 +99,11 @@ pub fn codegen(
         ));
     }
 
-    // if there's no user `#[idle]` then optimize returning from interrupt handlers
+    // If there's no user `#[idle]` then optimize returning from interrupt handlers
-    if app.idles.get(&core).is_none() {
+    if app.idles.is_empty() {
         // Set SLEEPONEXIT bit to enter sleep mode when returning from ISR
         stmts.push(quote!(core.SCB.scr.modify(|r| r | 1 << 1);));
     }
 
-    // cross-spawn barriers: wait until other cores are ready to receive messages
+    stmts
-    for (&receiver, senders) in &analysis.spawn_barriers {
-        // only block here if `init` can send messages to `receiver`
-        if senders.get(&core) == Some(&true) {
-            let sb = util::spawn_barrier(receiver);
-
-            stmts.push(quote!(
-                #sb.wait();
-            ));
-        }
-    }
-
-    (const_app, stmts)
 }

macros/src/codegen/resources.rs

@@ -1,9 +1,6 @@
 use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
-use rtic_syntax::{
+use rtic_syntax::{analyze::Ownership, ast::App};
-    analyze::{Location, Ownership},
-    ast::App,
-};
 
 use crate::{analyze::Analysis, check::Extra, codegen::util};
 
@@ -21,37 +18,15 @@ pub fn codegen(
     let mut const_app = vec![];
     let mut mod_resources = vec![];
 
-    for (name, res, expr, loc) in app.resources(analysis) {
+    for (name, res, expr, _) in app.resources(analysis) {
         let cfgs = &res.cfgs;
         let ty = &res.ty;
 
         {
-            let (loc_attr, section) = match loc {
+            let section = if expr.is_none() {
-                Location::Owned {
+                util::link_section_uninit(true)
-                    core,
-                    cross_initialized: false,
-                } => (
-                    util::cfg_core(*core, app.args.cores),
-                    if expr.is_none() {
-                        util::link_section_uninit(Some(*core))
-                    } else {
-                        util::link_section("data", *core)
-                    },
-                ),
-
-                // shared `static`s and cross-initialized resources need to be in `.shared` memory
-                _ => (
-                    if cfg!(feature = "heterogeneous") {
-                        Some(quote!(#[rtic::export::shared]))
             } else {
                 None
-                    },
-                    if expr.is_none() {
-                        util::link_section_uninit(None)
-                    } else {
-                        None
-                    },
-                ),
             };
 
             let (ty, expr) = if let Some(expr) = expr {
@@ -68,25 +43,20 @@ pub fn codegen(
                 #[allow(non_upper_case_globals)]
                 #(#attrs)*
                 #(#cfgs)*
-                #loc_attr
                 #section
                 static mut #name: #ty = #expr;
             ));
         }
 
         if let Some(Ownership::Contended { ceiling }) = analysis.ownerships.get(name) {
-            let cfg_core = util::cfg_core(loc.core().expect("UNREACHABLE"), app.args.cores);
-
             mod_resources.push(quote!(
                 #[allow(non_camel_case_types)]
                 #(#cfgs)*
-                #cfg_core
                 pub struct #name<'a> {
                     priority: &'a Priority,
                 }
 
                 #(#cfgs)*
-                #cfg_core
                 impl<'a> #name<'a> {
                     #[inline(always)]
                     pub unsafe fn new(priority: &'a Priority) -> Self {
@@ -115,7 +85,6 @@ pub fn codegen(
             const_app.push(util::impl_mutex(
                 extra,
                 cfgs,
-                cfg_core.as_ref(),
                 true,
                 name,
                 quote!(#ty),

macros/src/codegen/resources_struct.rs

@@ -14,8 +14,8 @@ pub fn codegen(
     let mut lt = None;
 
     let resources = match ctxt {
-        Context::Init(core) => &app.inits[&core].args.resources,
+        Context::Init => &app.inits.first().unwrap().args.resources,
-        Context::Idle(core) => &app.idles[&core].args.resources,
+        Context::Idle => &app.idles.first().unwrap().args.resources,
         Context::HardwareTask(name) => &app.hardware_tasks[name].args.resources,
         Context::SoftwareTask(name) => &app.software_tasks[name].args.resources,
     };
@@ -39,7 +39,7 @@ pub fn codegen(
 
         if ctxt.is_init() {
             if !analysis.ownerships.contains_key(name) {
-                // owned by `init`
+                // Owned by `init`
                 fields.push(quote!(
                     #(#cfgs)*
                     pub #name: &'static #mut_ #ty
@@ -50,7 +50,7 @@ pub fn codegen(
                     #name: &#mut_ #name
                 ));
             } else {
-                // owned by someone else
+                // Owned by someone else
                 lt = Some(quote!('a));
 
                 fields.push(quote!(
@@ -75,7 +75,7 @@ pub fn codegen(
                         pub #name: &'a #ty
                     ));
                 } else {
-                    // resource proxy
+                    // Resource proxy
                     lt = Some(quote!('a));
 
                     fields.push(quote!(
@@ -136,7 +136,7 @@ pub fn codegen(
     if lt.is_some() {
         *needs_lt = true;
 
-        // the struct could end up empty due to `cfg`s leading to an error due to `'a` being unused
+        // The struct could end up empty due to `cfg`s leading to an error due to `'a` being unused
         if has_cfgs {
             fields.push(quote!(
                 #[doc(hidden)]
@@ -147,13 +147,9 @@ pub fn codegen(
         }
     }
 
-    let core = ctxt.core(app);
-    let cores = app.args.cores;
-    let cfg_core = util::cfg_core(core, cores);
     let doc = format!("Resources `{}` has access to", ctxt.ident(app));
     let ident = util::resources_ident(ctxt, app);
     let item = quote!(
-        #cfg_core
         #[allow(non_snake_case)]
         #[doc = #doc]
         pub struct #ident<#lt> {
@@ -167,7 +163,6 @@ pub fn codegen(
         Some(quote!(priority: &#lt rtic::export::Priority))
     };
     let constructor = quote!(
-        #cfg_core
         impl<#lt> #ident<#lt> {
             #[inline(always)]
             unsafe fn new(#arg) -> Self {

macros/src/codegen/schedule.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, HashSet};
+use std::collections::HashSet;
 
 use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
@@ -13,14 +13,11 @@ use crate::{
 pub fn codegen(app: &App, extra: &Extra) -> Vec<TokenStream2> {
     let mut items = vec![];
 
-    let mut seen = BTreeMap::<u8, HashSet<_>>::new();
+    let mut seen = HashSet::<_>::new();
     for (scheduler, schedulees) in app.schedule_callers() {
         let m = extra.monotonic();
         let instant = quote!(<#m as rtic::Monotonic>::Instant);
 
-        let sender = scheduler.core(app);
-        let cfg_sender = util::cfg_core(sender, app.args.cores);
-        let seen = seen.entry(sender).or_default();
         let mut methods = vec![];
 
         for name in schedulees {
@@ -35,28 +32,23 @@ pub fn codegen(app: &App, extra: &Extra) -> Vec<TokenStream2> {
 
                 let body = schedule_body::codegen(scheduler, &name, app);
 
-                let section = util::link_section("text", sender);
                 methods.push(quote!(
                     #(#cfgs)*
-                    #section
                     fn #name(&self, instant: #instant #(,#args)*) -> Result<(), #ty> {
                         #body
                     }
                 ));
             } else {
-                let schedule = util::schedule_ident(name, sender);
+                let schedule = util::schedule_ident(name);
 
                 if !seen.contains(name) {
-                    // generate a `schedule_${name}_S${sender}` function
+                    // Generate a `schedule_${name}_S${sender}` function
                     seen.insert(name);
 
                     let body = schedule_body::codegen(scheduler, &name, app);
 
-                    let section = util::link_section("text", sender);
                     items.push(quote!(
-                        #cfg_sender
                         #(#cfgs)*
-                        #section
                         unsafe fn #schedule(
                             priority: &rtic::export::Priority,
                             instant: #instant
@@ -88,7 +80,6 @@ pub fn codegen(app: &App, extra: &Extra) -> Vec<TokenStream2> {
         let scheduler = scheduler.ident(app);
         debug_assert!(!methods.is_empty());
         items.push(quote!(
-            #cfg_sender
             impl<#lt> #scheduler::Schedule<#lt> {
                 #(#methods)*
             }

macros/src/codegen/schedule_body.rs

@@ -6,12 +6,10 @@ use syn::Ident;
 use crate::codegen::util;
 
 pub fn codegen(scheduler: Context, name: &Ident, app: &App) -> TokenStream2 {
-    let sender = scheduler.core(app);
     let schedulee = &app.software_tasks[name];
-    let receiver = schedulee.args.core;
 
-    let fq = util::fq_ident(name, sender);
+    let fq = util::fq_ident(name);
-    let tq = util::tq_ident(sender);
+    let tq = util::tq_ident();
     let (dequeue, enqueue) = if scheduler.is_init() {
         (quote!(#fq.dequeue()), quote!(#tq.enqueue_unchecked(nr);))
     } else {
@@ -21,8 +19,8 @@ pub fn codegen(scheduler: Context, name: &Ident, app: &App) -> TokenStream2 {
         )
     };
 
-    let write_instant = if app.uses_schedule(receiver) {
+    let write_instant = if app.uses_schedule() {
-        let instants = util::instants_ident(name, sender);
+        let instants = util::instants_ident(name);
 
         Some(quote!(
             #instants.get_unchecked_mut(usize::from(index)).as_mut_ptr().write(instant);
@@ -32,8 +30,8 @@ pub fn codegen(scheduler: Context, name: &Ident, app: &App) -> TokenStream2 {
     };
 
     let (_, tupled, _, _) = util::regroup_inputs(&schedulee.inputs);
-    let inputs = util::inputs_ident(name, sender);
+    let inputs = util::inputs_ident(name);
-    let t = util::schedule_t_ident(sender);
+    let t = util::schedule_t_ident();
     quote!(
         unsafe {
             use rtic::Mutex as _;

macros/src/codegen/software_tasks.rs

@@ -28,8 +28,6 @@ pub fn codegen(
     let mut user_tasks = vec![];
 
     for (name, task) in &app.software_tasks {
-        let receiver = task.args.core;
-
         let inputs = &task.inputs;
         let (_, _, _, input_ty) = util::regroup_inputs(inputs);
 
@@ -37,57 +35,28 @@ pub fn codegen(
         let cap_lit = util::capacity_literal(cap);
         let cap_ty = util::capacity_typenum(cap, true);
 
-        // create free queues and inputs / instants buffers
+        // Create free queues and inputs / instants buffers
-        if let Some(free_queues) = analysis.free_queues.get(name) {
+        if let Some(&ceiling) = analysis.free_queues.get(name) {
-            for (&sender, &ceiling) in free_queues {
+            let fq = util::fq_ident(name);
-                let cfg_sender = util::cfg_core(sender, app.args.cores);
-                let fq = util::fq_ident(name, sender);
 
-                let (loc, fq_ty, fq_expr, bss, mk_uninit): (
+            let (fq_ty, fq_expr, mk_uninit): (_, _, Box<dyn Fn() -> Option<_>>) = {
-                    _,
-                    _,
-                    _,
-                    _,
-                    Box<dyn Fn() -> Option<_>>,
-                ) = if receiver == sender {
                 (
-                        cfg_sender.clone(),
                     quote!(rtic::export::SCFQ<#cap_ty>),
                     quote!(rtic::export::Queue(unsafe {
                         rtic::export::iQueue::u8_sc()
                     })),
-                        util::link_section("bss", sender),
+                    Box::new(|| util::link_section_uninit(true)),
-                        Box::new(|| util::link_section_uninit(Some(sender))),
-                    )
-                } else {
-                    let shared = if cfg!(feature = "heterogeneous") {
-                        Some(quote!(#[rtic::export::shared]))
-                    } else {
-                        None
-                    };
-
-                    (
-                        shared,
-                        quote!(rtic::export::MCFQ<#cap_ty>),
-                        quote!(rtic::export::Queue(rtic::export::iQueue::u8())),
-                        None,
-                        Box::new(|| util::link_section_uninit(None)),
                 )
             };
-                let loc = &loc;
-
             const_app.push(quote!(
                 /// Queue version of a free-list that keeps track of empty slots in
                 /// the following buffers
-                    #loc
-                    #bss
                 static mut #fq: #fq_ty = #fq_expr;
             ));
 
             // Generate a resource proxy if needed
             if let Some(ceiling) = ceiling {
                 const_app.push(quote!(
-                        #cfg_sender
                     struct #fq<'a> {
                         priority: &'a rtic::export::Priority,
                     }
@@ -96,7 +65,6 @@ pub fn codegen(
                 const_app.push(util::impl_mutex(
                     extra,
                     &[],
-                        cfg_sender.as_ref(),
                     false,
                     &fq,
                     fq_ty,
@@ -109,13 +77,12 @@ pub fn codegen(
                 .map(|_| quote!(core::mem::MaybeUninit::uninit()))
                 .collect::<Vec<_>>();
 
-                if app.uses_schedule(receiver) {
+            if app.uses_schedule() {
                 let m = extra.monotonic();
-                    let instants = util::instants_ident(name, sender);
+                let instants = util::instants_ident(name);
 
                 let uninit = mk_uninit();
                 const_app.push(quote!(
-                        #loc
                     #uninit
                     /// Buffer that holds the instants associated to the inputs of a task
                     static mut #instants:
@@ -125,16 +92,14 @@ pub fn codegen(
             }
 
             let uninit = mk_uninit();
-                let inputs = util::inputs_ident(name, sender);
+            let inputs = util::inputs_ident(name);
             const_app.push(quote!(
-                    #loc
                 #uninit
                 /// Buffer that holds the inputs of a task
                 static mut #inputs: [core::mem::MaybeUninit<#input_ty>; #cap_lit] =
                     [#(#elems,)*];
             ));
         }
-        }
 
         // `${task}Resources`
         let mut needs_lt = false;
@@ -155,15 +120,12 @@ pub fn codegen(
         // `${task}Locals`
         let mut locals_pat = None;
         if !task.locals.is_empty() {
-            let (struct_, pat) =
+            let (struct_, pat) = locals::codegen(Context::SoftwareTask(name), &task.locals, app);
-                locals::codegen(Context::SoftwareTask(name), &task.locals, receiver, app);
 
             locals_pat = Some(pat);
             root.push(struct_);
         }
 
-        let cfg_receiver = util::cfg_core(receiver, app.args.cores);
-        let section = util::link_section("text", receiver);
         let context = &task.context;
         let attrs = &task.attrs;
         let cfgs = &task.cfgs;
@@ -173,8 +135,6 @@ pub fn codegen(
             #(#attrs)*
             #(#cfgs)*
             #[allow(non_snake_case)]
-            #cfg_receiver
-            #section
             fn #name(#(#locals_pat,)* #context: #name::Context #(,#inputs)*) {
                 use rtic::Mutex as _;
 

macros/src/codegen/spawn.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeMap, HashSet};
+use std::collections::HashSet;
 
 use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
@@ -14,16 +14,12 @@ use crate::{
 pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream2> {
     let mut items = vec![];
 
-    let mut seen = BTreeMap::<u8, HashSet<_>>::new();
+    let mut seen = HashSet::<_>::new();
     for (spawner, spawnees) in app.spawn_callers() {
-        let sender = spawner.core(app);
-        let cfg_sender = util::cfg_core(sender, app.args.cores);
-        let seen = seen.entry(sender).or_default();
         let mut methods = vec![];
 
         for name in spawnees {
             let spawnee = &app.software_tasks[name];
-            let receiver = spawnee.args.core;
             let cfgs = &spawnee.cfgs;
             let (args, _, untupled, ty) = util::regroup_inputs(&spawnee.inputs);
             let args = &args;
@@ -34,7 +30,7 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
 
                 let body = spawn_body::codegen(spawner, &name, app, analysis, extra);
 
-                let let_instant = if app.uses_schedule(receiver) {
+                let let_instant = if app.uses_schedule() {
                     let m = extra.monotonic();
 
                     Some(quote!(let instant = unsafe { <#m as rtic::Monotonic>::zero() };))
@@ -42,23 +38,21 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
                     None
                 };
 
-                let section = util::link_section("text", sender);
                 methods.push(quote!(
                     #(#cfgs)*
-                    #section
                     fn #name(&self #(,#args)*) -> Result<(), #ty> {
                         #let_instant
                         #body
                     }
                 ));
             } else {
-                let spawn = util::spawn_ident(name, sender);
+                let spawn = util::spawn_ident(name);
 
                 if !seen.contains(name) {
-                    // generate a `spawn_${name}_S${sender}` function
+                    // Generate a `spawn_${name}_S${sender}` function
                     seen.insert(name);
 
-                    let instant = if app.uses_schedule(receiver) {
+                    let instant = if app.uses_schedule() {
                         let m = extra.monotonic();
 
                         Some(quote!(, instant: <#m as rtic::Monotonic>::Instant))
@@ -68,11 +62,8 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
 
                     let body = spawn_body::codegen(spawner, &name, app, analysis, extra);
 
-                    let section = util::link_section("text", sender);
                     items.push(quote!(
-                        #cfg_sender
                         #(#cfgs)*
-                        #section
                         unsafe fn #spawn(
                             priority: &rtic::export::Priority
                             #instant
@@ -83,7 +74,7 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
                     ));
                 }
 
-                let (let_instant, instant) = if app.uses_schedule(receiver) {
+                let (let_instant, instant) = if app.uses_schedule() {
                     let m = extra.monotonic();
 
                     (
@@ -120,7 +111,6 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
         let spawner = spawner.ident(app);
         debug_assert!(!methods.is_empty());
         items.push(quote!(
-            #cfg_sender
             impl<#lt> #spawner::Spawn<#lt> {
                 #(#methods)*
             }

macros/src/codegen/spawn_body.rs

@@ -12,13 +12,11 @@ pub fn codegen(
     analysis: &Analysis,
     extra: &Extra,
 ) -> TokenStream2 {
-    let sender = spawner.core(app);
     let spawnee = &app.software_tasks[name];
     let priority = spawnee.args.priority;
-    let receiver = spawnee.args.core;
 
-    let write_instant = if app.uses_schedule(receiver) {
+    let write_instant = if app.uses_schedule() {
-        let instants = util::instants_ident(name, sender);
+        let instants = util::instants_ident(name);
 
         Some(quote!(
             #instants.get_unchecked_mut(usize::from(index)).as_mut_ptr().write(instant);
@@ -27,9 +25,9 @@ pub fn codegen(
         None
     };
 
-    let t = util::spawn_t_ident(receiver, priority, sender);
+    let t = util::spawn_t_ident(priority);
-    let fq = util::fq_ident(name, sender);
+    let fq = util::fq_ident(name);
-    let rq = util::rq_ident(receiver, priority, sender);
+    let rq = util::rq_ident(priority);
     let (dequeue, enqueue) = if spawner.is_init() {
         (
             quote!(#fq.dequeue()),
@@ -45,20 +43,16 @@ pub fn codegen(
     };
 
     let device = extra.device;
-    let enum_ = util::interrupt_ident(receiver, app.args.cores);
+    let enum_ = util::interrupt_ident();
-    let interrupt = &analysis.interrupts[&receiver][&priority];
+    let interrupt = &analysis.interrupts.get(&priority);
-    let pend = if sender != receiver {
+    let pend = {
-        quote!(
-            #device::xpend(#receiver, #device::#enum_::#interrupt);
-        )
-    } else {
         quote!(
             rtic::pend(#device::#enum_::#interrupt);
         )
     };
 
     let (_, tupled, _, _) = util::regroup_inputs(&spawnee.inputs);
-    let inputs = util::inputs_ident(name, sender);
+    let inputs = util::inputs_ident(name);
     quote!(
         unsafe {
             use rtic::Mutex as _;

macros/src/codegen/timer_queue.rs

@@ -8,9 +8,8 @@ use crate::{analyze::Analysis, check::Extra, codegen::util};
 pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream2> {
     let mut items = vec![];
 
-    for (&sender, timer_queue) in &analysis.timer_queues {
+    if let Some(timer_queue) = &analysis.timer_queues.first() {
-        let cfg_sender = util::cfg_core(sender, app.args.cores);
+        let t = util::schedule_t_ident();
-        let t = util::schedule_t_ident(sender);
 
         // Enumeration of `schedule`-able tasks
         {
@@ -27,9 +26,8 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
                 })
                 .collect::<Vec<_>>();
 
-            let doc = format!("Tasks that can be scheduled from core #{}", sender);
+            let doc = format!("Tasks that can be scheduled");
             items.push(quote!(
-                #cfg_sender
                 #[doc = #doc]
                 #[allow(non_camel_case_types)]
                 #[derive(Clone, Copy)]
@@ -39,27 +37,23 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             ));
         }
 
-        let tq = util::tq_ident(sender);
+        let tq = util::tq_ident();
 
         // Static variable and resource proxy
         {
-            let doc = format!("Core #{} timer queue", sender);
+            let doc = format!("Timer queue");
             let m = extra.monotonic();
             let n = util::capacity_typenum(timer_queue.capacity, false);
             let tq_ty = quote!(rtic::export::TimerQueue<#m, #t, #n>);
 
-            let section = util::link_section("bss", sender);
             items.push(quote!(
-                #cfg_sender
                 #[doc = #doc]
-                #section
                 static mut #tq: #tq_ty = rtic::export::TimerQueue(
                     rtic::export::BinaryHeap(
                         rtic::export::iBinaryHeap::new()
                     )
                 );
 
-                #cfg_sender
                 struct #tq<'a> {
                     priority: &'a rtic::export::Priority,
                 }
@@ -68,7 +62,6 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             items.push(util::impl_mutex(
                 extra,
                 &[],
-                cfg_sender.as_ref(),
                 false,
                 &tq,
                 tq_ty,
@@ -88,17 +81,12 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
 
                     let cfgs = &task.cfgs;
                     let priority = task.args.priority;
-                    let receiver = task.args.core;
+                    let rq = util::rq_ident(priority);
-                    let rq = util::rq_ident(receiver, priority, sender);
+                    let rqt = util::spawn_t_ident(priority);
-                    let rqt = util::spawn_t_ident(receiver, priority, sender);
+                    let enum_ = util::interrupt_ident();
-                    let enum_ = util::interrupt_ident(receiver, app.args.cores);
+                    let interrupt = &analysis.interrupts.get(&priority);
-                    let interrupt = &analysis.interrupts[&receiver][&priority];
 
-                    let pend = if sender != receiver {
+                    let pend = {
-                        quote!(
-                            #device::xpend(#receiver, #device::#enum_::#interrupt);
-                        )
-                    } else {
                         quote!(
                             rtic::pend(#device::#enum_::#interrupt);
                         )
@@ -118,12 +106,9 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
                 .collect::<Vec<_>>();
 
             let priority = timer_queue.priority;
-            let sys_tick = util::suffixed("SysTick", sender);
+            let sys_tick = util::suffixed("SysTick");
-            let section = util::link_section("text", sender);
             items.push(quote!(
                 #[no_mangle]
-                #cfg_sender
-                #section
                 unsafe fn #sys_tick() {
                     use rtic::Mutex as _;
 
@@ -148,6 +133,5 @@ pub fn codegen(app: &App, analysis: &Analysis, extra: &Extra) -> Vec<TokenStream
             ));
         }
     }
-
     items
 }

macros/src/codegen/util.rs

@@ -2,7 +2,7 @@ use core::sync::atomic::{AtomicUsize, Ordering};
 
 use proc_macro2::{Span, TokenStream as TokenStream2};
 use quote::quote;
-use rtic_syntax::{ast::App, Context, Core};
+use rtic_syntax::{ast::App, Context};
 use syn::{Attribute, Ident, LitInt, PatType};
 
 use crate::check::Extra;
@@ -25,34 +25,15 @@ pub fn capacity_typenum(capacity: u8, round_up_to_power_of_two: bool) -> TokenSt
     quote!(rtic::export::consts::#ident)
 }
 
-/// Generates a `#[cfg(core = "0")]` attribute if we are in multi-core mode
-pub fn cfg_core(core: Core, cores: u8) -> Option<TokenStream2> {
-    if cores == 1 {
-        None
-    } else if cfg!(feature = "heterogeneous") {
-        let core = core.to_string();
-        Some(quote!(#[cfg(core = #core)]))
-    } else {
-        None
-    }
-}
-
 /// Identifier for the free queue
-///
+pub fn fq_ident(task: &Ident) -> Ident {
-/// There may be more than one free queue per task because we need one for each sender core so we
+    Ident::new(&format!("{}_FQ", task.to_string()), Span::call_site())
-/// include the sender (e.g. `S0`) in the name
-pub fn fq_ident(task: &Ident, sender: Core) -> Ident {
-    Ident::new(
-        &format!("{}_S{}_FQ", task.to_string(), sender),
-        Span::call_site(),
-    )
 }
 
 /// Generates a `Mutex` implementation
 pub fn impl_mutex(
     extra: &Extra,
     cfgs: &[Attribute],
-    cfg_core: Option<&TokenStream2>,
     resources_prefix: bool,
     name: &Ident,
     ty: TokenStream2,
@@ -68,7 +49,6 @@ pub fn impl_mutex(
     let device = extra.device;
     quote!(
         #(#cfgs)*
-        #cfg_core
         impl<'a> rtic::Mutex for #path<'a> {
             type T = #ty;
 
@@ -91,28 +71,19 @@ pub fn impl_mutex(
     )
 }
 
-/// Generates an identifier for a cross-initialization barrier
-pub fn init_barrier(initializer: Core) -> Ident {
-    Ident::new(&format!("IB{}", initializer), Span::call_site())
-}
-
 /// Generates an identifier for the `INPUTS` buffer (`spawn` & `schedule` API)
-pub fn inputs_ident(task: &Ident, sender: Core) -> Ident {
+pub fn inputs_ident(task: &Ident) -> Ident {
-    Ident::new(&format!("{}_S{}_INPUTS", task, sender), Span::call_site())
+    Ident::new(&format!("{}_INPUTS", task), Span::call_site())
 }
 
 /// Generates an identifier for the `INSTANTS` buffer (`schedule` API)
-pub fn instants_ident(task: &Ident, sender: Core) -> Ident {
+pub fn instants_ident(task: &Ident) -> Ident {
-    Ident::new(&format!("{}_S{}_INSTANTS", task, sender), Span::call_site())
+    Ident::new(&format!("{}_INSTANTS", task), Span::call_site())
 }
 
-pub fn interrupt_ident(core: Core, cores: u8) -> Ident {
+pub fn interrupt_ident() -> Ident {
     let span = Span::call_site();
-    if cores == 1 {
     Ident::new("Interrupt", span)
-    } else {
-        Ident::new(&format!("Interrupt_{}", core), span)
-    }
 }
 
 /// Whether `name` is an exception with configurable priority
@@ -141,31 +112,12 @@ fn link_section_index() -> usize {
     INDEX.fetch_add(1, Ordering::Relaxed)
 }
 
-pub fn link_section(section: &str, core: Core) -> Option<TokenStream2> {
-    if cfg!(feature = "homogeneous") {
-        let section = format!(".{}_{}.rtic{}", section, core, link_section_index());
-        Some(quote!(#[link_section = #section]))
-    } else {
-        None
-    }
-}
-
 // NOTE `None` means in shared memory
-pub fn link_section_uninit(core: Option<Core>) -> Option<TokenStream2> {
+pub fn link_section_uninit(empty_expr: bool) -> Option<TokenStream2> {
-    let section = if let Some(core) = core {
+    let section = if empty_expr {
         let index = link_section_index();
-
-        if cfg!(feature = "homogeneous") {
-            format!(".uninit_{}.rtic{}", core, index)
-        } else {
         format!(".uninit.rtic{}", index)
-        }
     } else {
-        if cfg!(feature = "heterogeneous") {
-            // `#[shared]` attribute sets the linker section
-            return None;
-        }
-
         format!(".uninit.rtic{}", link_section_index())
     };
 
@@ -175,8 +127,8 @@ pub fn link_section_uninit(core: Option<Core>) -> Option<TokenStream2> {
 /// Generates a pre-reexport identifier for the "locals" struct
 pub fn locals_ident(ctxt: Context, app: &App) -> Ident {
     let mut s = match ctxt {
-        Context::Init(core) => app.inits[&core].name.to_string(),
+        Context::Init => app.inits.first().unwrap().name.to_string(),
-        Context::Idle(core) => app.idles[&core].name.to_string(),
+        Context::Idle => app.idles.first().unwrap().name.to_string(),
         Context::HardwareTask(ident) | Context::SoftwareTask(ident) => ident.to_string(),
     };
 
@@ -185,11 +137,6 @@ pub fn locals_ident(ctxt: Context, app: &App) -> Ident {
     Ident::new(&s, Span::call_site())
 }
 
-/// Generates an identifier for a rendezvous barrier
-pub fn rendezvous_ident(core: Core) -> Ident {
-    Ident::new(&format!("RV{}", core), Span::call_site())
-}
-
 // Regroups the inputs of a task
 //
 // `inputs` could be &[`input: Foo`] OR &[`mut x: i32`, `ref y: i64`]
@@ -242,8 +189,8 @@ pub fn regroup_inputs(
 /// Generates a pre-reexport identifier for the "resources" struct
 pub fn resources_ident(ctxt: Context, app: &App) -> Ident {
     let mut s = match ctxt {
-        Context::Init(core) => app.inits[&core].name.to_string(),
+        Context::Init => app.inits.first().unwrap().name.to_string(),
-        Context::Idle(core) => app.idles[&core].name.to_string(),
+        Context::Idle => app.idles.first().unwrap().name.to_string(),
         Context::HardwareTask(ident) | Context::SoftwareTask(ident) => ident.to_string(),
     };
 
@@ -254,72 +201,47 @@ pub fn resources_ident(ctxt: Context, app: &App) -> Ident {
 
 /// Generates an identifier for a ready queue
 ///
-/// Each core may have several task dispatchers, one for each priority level. Each task dispatcher
+/// There may be several task dispatchers, one for each priority level.
-/// in turn may use more than one ready queue because the queues are SPSC queues so one is needed
+/// The ready queues are SPSC queues
-/// per sender core.
+pub fn rq_ident(priority: u8) -> Ident {
-pub fn rq_ident(receiver: Core, priority: u8, sender: Core) -> Ident {
+    Ident::new(&format!("P{}_RQ", priority), Span::call_site())
-    Ident::new(
-        &format!("R{}_P{}_S{}_RQ", receiver, priority, sender),
-        Span::call_site(),
-    )
 }
 
 /// Generates an identifier for a "schedule" function
 ///
-/// The methods of the `Schedule` structs invoke these functions. As one task may be `schedule`-ed
+/// The methods of the `Schedule` structs invoke these functions.
-/// by different cores we need one "schedule" function per possible task-sender pair
+pub fn schedule_ident(name: &Ident) -> Ident {
-pub fn schedule_ident(name: &Ident, sender: Core) -> Ident {
+    Ident::new(&format!("schedule_{}", name.to_string()), Span::call_site())
-    Ident::new(
-        &format!("schedule_{}_S{}", name.to_string(), sender),
-        Span::call_site(),
-    )
 }
 
 /// Generates an identifier for the `enum` of `schedule`-able tasks
-pub fn schedule_t_ident(core: Core) -> Ident {
+pub fn schedule_t_ident() -> Ident {
-    Ident::new(&format!("T{}", core), Span::call_site())
+    Ident::new(&format!("T"), Span::call_site())
-}
-
-/// Generates an identifier for a cross-spawn barrier
-pub fn spawn_barrier(receiver: Core) -> Ident {
-    Ident::new(&format!("SB{}", receiver), Span::call_site())
 }
 
 /// Generates an identifier for a "spawn" function
 ///
-/// The methods of the `Spawn` structs invoke these functions. As one task may be `spawn`-ed by
+/// The methods of the `Spawn` structs invoke these functions.
-/// different cores we need one "spawn" function per possible task-sender pair
+pub fn spawn_ident(name: &Ident) -> Ident {
-pub fn spawn_ident(name: &Ident, sender: Core) -> Ident {
+    Ident::new(&format!("spawn_{}", name.to_string()), Span::call_site())
-    Ident::new(
-        &format!("spawn_{}_S{}", name.to_string(), sender),
-        Span::call_site(),
-    )
 }
 
 /// Generates an identifier for the `enum` of `spawn`-able tasks
 ///
 /// This identifier needs the same structure as the `RQ` identifier because there's one ready queue
 /// for each of these `T` enums
-pub fn spawn_t_ident(receiver: Core, priority: u8, sender: Core) -> Ident {
+pub fn spawn_t_ident(priority: u8) -> Ident {
-    Ident::new(
+    Ident::new(&format!("P{}_T", priority), Span::call_site())
-        &format!("R{}_P{}_S{}_T", receiver, priority, sender),
-        Span::call_site(),
-    )
 }
 
-pub fn suffixed(name: &str, core: u8) -> Ident {
+pub fn suffixed(name: &str) -> Ident {
     let span = Span::call_site();
-
-    if cfg!(feature = "homogeneous") {
-        Ident::new(&format!("{}_{}", name, core), span)
-    } else {
     Ident::new(name, span)
 }
-}
 
 /// Generates an identifier for a timer queue
 ///
-/// At most there's one timer queue per core
+/// At most there is one timer queue
-pub fn tq_ident(core: Core) -> Ident {
+pub fn tq_ident() -> Ident {
-    Ident::new(&format!("TQ{}", core), Span::call_site())
+    Ident::new(&format!("TQ"), Span::call_site())
 }

macros/src/lib.rs

@@ -201,12 +201,12 @@ mod tests;
 ///
 /// Attributes can be applied to the functions inside this block. These attributes will be forwarded
 /// to the interrupt handlers generated by the `app` attribute.
+
 #[proc_macro_attribute]
 pub fn app(args: TokenStream, input: TokenStream) -> TokenStream {
     let mut settings = Settings::default();
     settings.optimize_priorities = true;
     settings.parse_binds = true;
-    settings.parse_cores = cfg!(feature = "heterogeneous") || cfg!(feature = "homogeneous");
     settings.parse_extern_interrupt = true;
     settings.parse_schedule = true;
 

macros/src/tests.rs

@@ -1,5 +1,4 @@
 // NOTE these tests are specific to the Cortex-M port; `rtic-syntax` has a more extensive test suite
 // that tests functionality common to all the RTIC ports
 
-mod multi;
 mod single;

macros/src/tests/multi.rs

@@ -1,59 +0,0 @@
-use quote::quote;
-use rtic_syntax::Settings;
-
-#[test]
-fn analyze() {
-    let mut settings = Settings::default();
-    settings.parse_cores = true;
-    settings.parse_extern_interrupt = true;
-
-    let (app, analysis) = rtic_syntax::parse2(
-        quote!(device = pac, cores = 2),
-        quote!(
-            const APP: () = {
-                #[task(core = 0, priority = 1)]
-                fn a(_: a::Context) {}
-
-                #[task(core = 0, priority = 2)]
-                fn b(_: b::Context) {}
-
-                #[task(core = 1, priority = 1)]
-                fn c(_: c::Context) {}
-
-                #[task(core = 1, priority = 2)]
-                fn d(_: d::Context) {}
-
-                // first interrupt is assigned to the highest priority dispatcher
-                extern "C" {
-                    #[core = 0]
-                    fn B();
-
-                    #[core = 0]
-                    fn A();
-
-                    #[core = 1]
-                    fn A();
-
-                    #[core = 1]
-                    fn C();
-                }
-            };
-        ),
-        settings,
-    )
-    .unwrap();
-
-    let analysis = crate::analyze::app(analysis, &app);
-
-    // first core
-    let interrupts0 = &analysis.interrupts[&0];
-    assert_eq!(interrupts0.len(), 2);
-    assert_eq!(interrupts0[&2].to_string(), "B");
-    assert_eq!(interrupts0[&1].to_string(), "A");
-
-    // second core
-    let interrupts1 = &analysis.interrupts[&1];
-    assert_eq!(interrupts1.len(), 2);
-    assert_eq!(interrupts1[&2].to_string(), "A");
-    assert_eq!(interrupts1[&1].to_string(), "C");
-}

macros/src/tests/single.rs

@@ -15,7 +15,7 @@ fn analyze() {
                 #[task(priority = 2)]
                 fn b(_: b::Context) {}
 
-                // first interrupt is assigned to the highest priority dispatcher
+                // First interrupt is assigned to the highest priority dispatcher
                 extern "C" {
                     fn B();
                     fn A();
@@ -27,7 +27,7 @@ fn analyze() {
     .unwrap();
 
     let analysis = crate::analyze::app(analysis, &app);
-    let interrupts = &analysis.interrupts[&0];
+    let interrupts = &analysis.interrupts;
     assert_eq!(interrupts.len(), 2);
     assert_eq!(interrupts[&2].to_string(), "B");
     assert_eq!(interrupts[&1].to_string(), "A");

src/cyccnt.rs

@@ -19,10 +19,6 @@ use crate::Fraction;
 /// Adding or subtracting a `Duration` of more than `(1 << 31)` cycles to an `Instant` effectively
 /// makes it "wrap around" and creates an incorrect value. This is also true if the operation is
 /// done in steps, e.g. `(instant + dur) + dur` where `dur` is `(1 << 30)` ticks.
-///
-/// In multi-core contexts: this value is tied to the CYCCNT of *one* core so sending it a different
-/// core makes it lose its meaning -- each Cortex-M core has its own CYCCNT counter and these are
-/// usually unsynchronized and may even be running at different frequencies.
 #[derive(Clone, Copy, Eq, PartialEq)]
 pub struct Instant {
     inner: i32,

src/export.rs

@@ -12,14 +12,12 @@ pub use cortex_m::{
     peripheral::{scb::SystemHandler, syst::SystClkSource, DWT, NVIC},
     Peripherals,
 };
-use heapless::spsc::{MultiCore, SingleCore};
+use heapless::spsc::SingleCore;
 pub use heapless::{consts, i::Queue as iQueue, spsc::Queue};
 pub use heapless::{i::BinaryHeap as iBinaryHeap, BinaryHeap};
 #[cfg(feature = "heterogeneous")]
 pub use microamp::shared;
 
-pub type MCFQ<N> = Queue<u8, N, u8, MultiCore>;
-pub type MCRQ<T, N> = Queue<(T, u8), N, u8, MultiCore>;
 pub type SCFQ<N> = Queue<u8, N, u8, SingleCore>;
 pub type SCRQ<T, N> = Queue<(T, u8), N, u8, SingleCore>;
 
@@ -30,7 +28,7 @@ where
     F: FnOnce(),
 {
     if priority == 1 {
-        // if the priority of this interrupt is `1` then BASEPRI can only be `0`
+        // If the priority of this interrupt is `1` then BASEPRI can only be `0`
         f();
         unsafe { basepri::write(0) }
     } else {
@@ -82,7 +80,7 @@ impl Priority {
         }
     }
 
-    // these two methods are used by `lock` (see below) but can't be used from the RTIC application
+    // These two methods are used by `lock` (see below) but can't be used from the RTIC application
     #[inline(always)]
     fn set(&self, value: u8) {
         self.inner.set(value)
@@ -108,13 +106,6 @@ where
 {
 }
 
-#[inline(always)]
-pub fn assert_multicore<T>()
-where
-    T: super::MultiCore,
-{
-}
-
 #[cfg(armv7m)]
 #[inline(always)]
 pub unsafe fn lock<T, R>(

src/lib.rs

@@ -28,13 +28,6 @@
 //! release.
 //!
 //! [SemVer]: https://semver.org/spec/v2.0.0.html
-//!
-//! # Cargo features
-//!
-//! - `heterogeneous`. This opt-in feature enables the *experimental* heterogeneous multi-core
-//! support. This feature depends on unstable feature and requires the use of the nightly channel.
-//!
-//! - `homogeneous`. This opt-in feature enables the *experimental* homogeneous multi-core support.
 
 #![deny(missing_docs)]
 #![deny(rust_2018_compatibility)]
@@ -48,7 +41,6 @@ use cortex_m::{
     interrupt::Nr,
     peripheral::{CBP, CPUID, DCB, DWT, FPB, FPU, ITM, MPU, NVIC, SCB, TPIU},
 };
-#[cfg(all(not(feature = "heterogeneous"), not(feature = "homogeneous")))]
 use cortex_m_rt as _; // vector table
 pub use cortex_m_rtic_macros::app;
 pub use rtic_core::{Exclusive, Mutex};
@@ -161,9 +153,6 @@ pub trait Monotonic {
     fn zero() -> Self::Instant;
 }
 
-/// A marker trait that indicates that it is correct to use this type in multi-core context
-pub trait MultiCore {}
-
 /// Sets the given `interrupt` as pending
 ///
 /// This is a convenience function around

src/tq.rs

@@ -40,7 +40,7 @@ where
                 mem::transmute::<_, SYST>(()).enable_interrupt();
             }
 
-            // set SysTick pending
+            // Set SysTick pending
             SCB::set_pendst();
         }
 
@@ -79,13 +79,13 @@ where
                     };
                     mem::transmute::<_, SYST>(()).set_reload(dur);
 
-                    // start counting down from the new reload
+                    // Start counting down from the new reload
                     mem::transmute::<_, SYST>(()).clear_current();
 
                     None
                 }
             } else {
-                // the queue is empty
+                // The queue is empty
                 mem::transmute::<_, SYST>(()).disable_interrupt();
 
                 None