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/avr.rs | 57 +++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 vendor/portable-atomic/src/imp/interrupt/avr.rs (limited to 'vendor/portable-atomic/src/imp/interrupt/avr.rs') diff --git a/vendor/portable-atomic/src/imp/interrupt/avr.rs b/vendor/portable-atomic/src/imp/interrupt/avr.rs new file mode 100644 index 0000000..76d99c1 --- /dev/null +++ b/vendor/portable-atomic/src/imp/interrupt/avr.rs @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +// Adapted from https://github.com/Rahix/avr-device. +// +// Refs: +// - AVR Instruction Set Manual https://ww1.microchip.com/downloads/en/DeviceDoc/AVR-InstructionSet-Manual-DS40002198.pdf + +#[cfg(not(portable_atomic_no_asm))] +use core::arch::asm; + +pub(super) type State = u8; + +/// Disables interrupts and returns the previous interrupt state. +#[inline] +pub(super) fn disable() -> State { + let sreg: State; + // SAFETY: reading the status register (SREG) 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 CLI modifies the I bit of the status register (SREG). + // Refs: https://ww1.microchip.com/downloads/en/DeviceDoc/AVR-InstructionSet-Manual-DS40002198.pdf#page=58 + #[cfg(not(portable_atomic_no_asm))] + asm!( + "in {0}, 0x3F", + "cli", + out(reg) sreg, + options(nostack), + ); + #[cfg(portable_atomic_no_asm)] + { + llvm_asm!("in $0, 0x3F" : "=r"(sreg) ::: "volatile"); + llvm_asm!("cli" ::: "memory" : "volatile"); + } + } + sreg +} + +/// Restores the previous interrupt state. +/// +/// # Safety +/// +/// The state must be the one retrieved by the previous `disable`. +#[inline] +pub(super) unsafe fn restore(sreg: State) { + // SAFETY: the caller must guarantee that the state was retrieved by the previous `disable`, + unsafe { + // This clobbers the entire status register. See msp430.rs to safety on this. + // + // Do not use `nomem` and `readonly` because prevent preceding memory accesses from being reordered after interrupts are enabled. + // Do not use `preserves_flags` because OUT modifies the status register (SREG). + #[cfg(not(portable_atomic_no_asm))] + asm!("out 0x3F, {0}", in(reg) sreg, options(nostack)); + #[cfg(portable_atomic_no_asm)] + llvm_asm!("out 0x3F, $0" :: "r"(sreg) : "memory" : "volatile"); + } +} -- cgit v1.2.3