Crate atomic_maybe_uninit

Expand description

Atomic operations on potentially uninitialized integers.

Motivation

Copying types containing uninitialized bytes (e.g., padding), via the standard library’s atomic types is undefined behavior because the copy goes through integers.

This crate provides a way to soundly perform such operations.

Platform Support

Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, PowerPC, s390x, MSP430, AVR, and Hexagon are supported.

target_arch	primitives	load/store	swap/CAS
x86	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓
x86_64	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓
x86_64 (+cmpxchg16b) [5]	i128,u128	✓	✓
arm (v6+ or Linux/Android)	isize,usize,i8,u8,i16,u16,i32,u32	✓	✓[1]
arm (except for M-profile) [2]	i64,u64	✓	✓
aarch64	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128	✓	✓
riscv32	isize,usize,i8,u8,i16,u16,i32,u32	✓	✓[1]
riscv64	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓[1]
loongarch64 [3]	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓
mips / mips32r6 [4]	isize,usize,i8,u8,i16,u16,i32,u32	✓	✓
mips64 / mips64r6 [4]	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓
powerpc [4]	isize,usize,i8,u8,i16,u16,i32,u32	✓	✓
powerpc64 [4]	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓
powerpc64 (pwr8+) [4] [6]	i128,u128	✓	✓
s390x [4]	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128	✓	✓
msp430 [4]	isize,usize,i8,u8,i16,u16	✓
avr [4] (experimental)	isize,usize,i8,u8,i16,u16	✓
hexagon [4] (experimental)	isize,usize,i8,u8,i16,u16,i32,u32,i64,u64	✓	✓

[1] ARM’s atomic RMW operations are not available on v6-m (thumbv6m). RISC-V’s atomic RMW operations are not available on targets without the A (or G which means IMAFD) extension such as riscv32i, riscv32imc, etc.
[2] ARMv6+ or Linux/Android, except for M-profile architecture such as thumbv6m, thumbv7m, etc.
[3] Requires Rust 1.72+.
[4] Requires nightly due to #![feature(asm_experimental_arch)].
[5] Requires cmpxchg16b target feature (enabled by default on Apple targets).
[6] Requires target-cpu pwr8+ (powerpc64le is pwr8 by default).

Feel free to submit an issue if your target is not supported yet.

portable-atomic: Portable atomic types including support for 128-bit atomics, atomic float, etc.
atomic-memcpy: Byte-wise atomic memcpy.

Modules

raw
Low level API.

Macros

Structs