From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001 From: Valentin Popov Date: Mon, 8 Jan 2024 01:21:28 +0400 Subject: Initial vendor packages Signed-off-by: Valentin Popov --- vendor/portable-atomic/src/imp/interrupt/msp430.rs | 64 ++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 vendor/portable-atomic/src/imp/interrupt/msp430.rs (limited to 'vendor/portable-atomic/src/imp/interrupt/msp430.rs') diff --git a/vendor/portable-atomic/src/imp/interrupt/msp430.rs b/vendor/portable-atomic/src/imp/interrupt/msp430.rs new file mode 100644 index 0000000..8c1ca80 --- /dev/null +++ b/vendor/portable-atomic/src/imp/interrupt/msp430.rs @@ -0,0 +1,64 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +// Adapted from https://github.com/rust-embedded/msp430. +// +// See also src/imp/msp430.rs. +// +// Refs: https://www.ti.com/lit/ug/slau208q/slau208q.pdf + +#[cfg(not(portable_atomic_no_asm))] +use core::arch::asm; + +pub(super) use super::super::msp430 as atomic; + +pub(super) type State = u16; + +/// Disables interrupts and returns the previous interrupt state. +#[inline] +pub(super) fn disable() -> State { + let r: State; + // SAFETY: reading the status register and disabling interrupts are safe. + // (see module-level comments of interrupt/mod.rs on the safety of using privileged instructions) + unsafe { + // Do not use `nomem` and `readonly` because prevent subsequent memory accesses from being reordered before interrupts are disabled. + // Do not use `preserves_flags` because DINT modifies the GIE (global interrupt enable) bit of the status register. + #[cfg(not(portable_atomic_no_asm))] + asm!( + "mov R2, {0}", + "dint {{ nop", + out(reg) r, + options(nostack), + ); + #[cfg(portable_atomic_no_asm)] + { + llvm_asm!("mov R2, $0" : "=r"(r) ::: "volatile"); + llvm_asm!("dint { nop" ::: "memory" : "volatile"); + } + } + r +} + +/// Restores the previous interrupt state. +/// +/// # Safety +/// +/// The state must be the one retrieved by the previous `disable`. +#[inline] +pub(super) unsafe fn restore(r: State) { + // SAFETY: the caller must guarantee that the state was retrieved by the previous `disable`, + unsafe { + // This clobbers the entire status register, but we never explicitly modify + // flags within a critical session, and the only flags that may be changed + // within a critical session are the arithmetic flags that are changed as + // a side effect of arithmetic operations, etc., which LLVM recognizes, + // so it is safe to clobber them here. + // See also the discussion at https://github.com/taiki-e/portable-atomic/pull/40. + // + // Do not use `nomem` and `readonly` because prevent preceding memory accesses from being reordered after interrupts are enabled. + // Do not use `preserves_flags` because MOV modifies the status register. + #[cfg(not(portable_atomic_no_asm))] + asm!("nop {{ mov {0}, R2 {{ nop", in(reg) r, options(nostack)); + #[cfg(portable_atomic_no_asm)] + llvm_asm!("nop { mov $0, R2 { nop" :: "r"(r) : "memory" : "volatile"); + } +} -- cgit v1.2.3