Crate atomic_maybe_uninit
source · [−]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 (v6+), AArch64, RISC-V, MIPS32r2, MIPS64r2, PowerPC, and s390x are supported.
| target_arch | primitives | load/store | swap | CAS |
|---|---|---|---|---|
| x86 | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64 | ✓ | ✓ | ✓[1] |
| x86_64 | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64 | ✓ | ✓ | ✓ |
| x86_64 (+cmpxchg16b) | i128,u128 | ✓ | ✓ | ✓ |
| arm (v6+) | isize,usize,i8,u8,i16,u16,i32,u32 | ✓ | ✓[1] | ✓[1] |
| arm (v6 except v6-m, v7-a) | i64,u64 | ✓ | ✓ | ✓ |
| aarch64 [2] | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓ | ✓ | ✓ |
| riscv32 | isize,usize,i8,u8,i16,u16,i32,u32 | ✓ | ✓[1] | ✓[1] |
| riscv64 | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64 | ✓ | ✓[1] | ✓[1] |
| mips [3] | isize,usize,i8,u8,i16,u16,i32,u32 | ✓ | ✓ | ✓ |
| mips64 [3] | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64 | ✓ | ✓ | ✓ |
| powerpc [3] | isize,usize,i8,u8,i16,u16,i32,u32 | ✓ | ✓ | ✓ |
| powerpc64 [3] | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64 | ✓ | ✓ | ✓ |
| powerpc64 (le or pwr8+) [3] [4] | i128,u128 | ✓ | ✓ | ✓ |
| s390x [3] | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓ | ✓ | ✓ |
[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) extension such as riscv32i, riscv32imc, etc. x86’s atomic CAS is not available on i386 (80386).
[2] If target features such as lse and lse2 are enabled at compile-time, more efficient instructions are used.
[3] Requires nightly due to #![feature(asm_experimental_arch)].
[4] target-cpu pwr8, pwr9, or pwr10.
Feel free to submit an issue if your target is not supported yet.
Related Projects
- portable-atomic: Portable atomic types including support for 128-bit atomics, atomic float, etc.
- atomic-memcpy: Byte-wise atomic memcpy.
Modules
Low level API.
Structs
A potentially uninitialized integer type which can be safely shared between threads.