Support/avr platform #12
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This commit adds support for AVR (Arduino) platforms via direct implementation of interrupt enable/disable functionality via AVR assembly. The underlying motivation for this support is to enable further integration with the greater Embedded Rust ecosystem. As an example, `embedded-nal` depends upon `heapless`, which in turn depends upon atomic support, either natively or via `atomic-polyfill`. `atomic-polyfill` uses `critical-section`, and so enabling AVR support in this crate has great benefits to the downstream packages that hvae come to depend upon `critical-section`.
…and feature(llvm_asm). Also had to disable #
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The CI check appears to have choked because |
ci.sh
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| @@ -7,3 +7,4 @@ cargo build --target thumbv6m-none-eabi | |||
| cargo build --target thumbv7em-none-eabi | |||
| cargo build --target riscv32imc-unknown-none-elf | |||
| cargo build --target riscv32imac-unknown-none-elf | |||
| cargo +nightly-2021-01-07 build -Zbuild-std=core --target avr-specs/avr-atmega328p.json | |||
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Is there a reason to use such an old nightly?
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Yes. Attempting to use a modern version of rust fails with
error: ran out of registers during register allocation
It may be covered by rust-lang/rust#88252 , but Rust on AVR has been waiting for a fix for a long time and has to muddle along with old tools.
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oh, I see. No problem then, was just curious :)
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I wonder if it is possible to just rustup install nightly-2021-01-07 in the ci.sh, but I don't know how to test it without pushing another commit.
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See my comment in the main thread. also feel free to push as many commits as you need! you can squash/amend later.
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I found a way to make ci.sh work. I just did a rustup toolchain install nightly-2021-01-07 --component rust-src before I compile for AVR. There might be a more elegant way to do it, but I do not know what it would be.
| #[no_mangle] | ||
| unsafe fn _critical_section_acquire() -> u8 { | ||
| let mut sreg: u8; | ||
| llvm_asm!( |
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Is it possible to use the newer asm!, or is it not supported on AVR?
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Last I checked asm! was not supported by Rust for AVR target.
- llvm_asm! removed in latest nightly rust Rahix/avr-device#91
- llvm_asm macro has been deprecated avr-rust/delay#10
Also, the last time I dealt with assembly language was 1987 on an 8086.
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Okay, just wanted to confirm!
Also, the last time I dealt with assembly language was 1987 on an 8086.
😂
It's standard |
…te rust toolchain
…alternate rust toolchain
torrancew's pull request #6 seems to have stalled. I picked up where it left off and performed the changes to the CI system you requested. Let me know if there is anything else you would like adjusted.