diff options
Diffstat (limited to 'library/stdarch/crates/core_arch/src/wasm32/atomic.rs')
-rw-r--r-- | library/stdarch/crates/core_arch/src/wasm32/atomic.rs | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/library/stdarch/crates/core_arch/src/wasm32/atomic.rs b/library/stdarch/crates/core_arch/src/wasm32/atomic.rs new file mode 100644 index 000000000..52d4bea87 --- /dev/null +++ b/library/stdarch/crates/core_arch/src/wasm32/atomic.rs @@ -0,0 +1,93 @@ +#[cfg(test)] +use stdarch_test::assert_instr; + +extern "C" { + #[link_name = "llvm.wasm.memory.atomic.wait32"] + fn llvm_atomic_wait_i32(ptr: *mut i32, exp: i32, timeout: i64) -> i32; + #[link_name = "llvm.wasm.memory.atomic.wait64"] + fn llvm_atomic_wait_i64(ptr: *mut i64, exp: i64, timeout: i64) -> i32; + #[link_name = "llvm.wasm.memory.atomic.notify"] + fn llvm_atomic_notify(ptr: *mut i32, cnt: i32) -> i32; +} + +/// Corresponding intrinsic to wasm's [`memory.atomic.wait32` instruction][instr] +/// +/// This function, when called, will block the current thread if the memory +/// pointed to by `ptr` is equal to `expression` (performing this action +/// atomically). +/// +/// The argument `timeout_ns` is a maximum number of nanoseconds the calling +/// thread will be blocked for, if it blocks. If the timeout is negative then +/// the calling thread will be blocked forever. +/// +/// The calling thread can only be woken up with a call to the `wake` intrinsic +/// once it has been blocked. Changing the memory behind `ptr` will not wake +/// the thread once it's blocked. +/// +/// # Return value +/// +/// * 0 - indicates that the thread blocked and then was woken up +/// * 1 - the loaded value from `ptr` didn't match `expression`, the thread +/// didn't block +/// * 2 - the thread blocked, but the timeout expired. +/// +/// [instr]: https://webassembly.github.io/threads/core/syntax/instructions.html#syntax-instr-atomic-memory +#[inline] +#[cfg_attr(test, assert_instr(memory.atomic.wait32))] +#[target_feature(enable = "atomics")] +#[doc(alias("memory.atomic.wait32"))] +pub unsafe fn memory_atomic_wait32(ptr: *mut i32, expression: i32, timeout_ns: i64) -> i32 { + llvm_atomic_wait_i32(ptr, expression, timeout_ns) +} + +/// Corresponding intrinsic to wasm's [`memory.atomic.wait64` instruction][instr] +/// +/// This function, when called, will block the current thread if the memory +/// pointed to by `ptr` is equal to `expression` (performing this action +/// atomically). +/// +/// The argument `timeout_ns` is a maximum number of nanoseconds the calling +/// thread will be blocked for, if it blocks. If the timeout is negative then +/// the calling thread will be blocked forever. +/// +/// The calling thread can only be woken up with a call to the `wake` intrinsic +/// once it has been blocked. Changing the memory behind `ptr` will not wake +/// the thread once it's blocked. +/// +/// # Return value +/// +/// * 0 - indicates that the thread blocked and then was woken up +/// * 1 - the loaded value from `ptr` didn't match `expression`, the thread +/// didn't block +/// * 2 - the thread blocked, but the timeout expired. +/// +/// [instr]: https://webassembly.github.io/threads/core/syntax/instructions.html#syntax-instr-atomic-memory +#[inline] +#[cfg_attr(test, assert_instr(memory.atomic.wait64))] +#[target_feature(enable = "atomics")] +#[doc(alias("memory.atomic.wait64"))] +pub unsafe fn memory_atomic_wait64(ptr: *mut i64, expression: i64, timeout_ns: i64) -> i32 { + llvm_atomic_wait_i64(ptr, expression, timeout_ns) +} + +/// Corresponding intrinsic to wasm's [`memory.atomic.notify` instruction][instr] +/// +/// This function will notify a number of threads blocked on the address +/// indicated by `ptr`. Threads previously blocked with the `i32_atomic_wait` +/// and `i64_atomic_wait` functions above will be woken up. +/// +/// The `waiters` argument indicates how many waiters should be woken up (a +/// maximum). If the value is zero no waiters are woken up. +/// +/// # Return value +/// +/// Returns the number of waiters which were actually notified. +/// +/// [instr]: https://webassembly.github.io/threads/core/syntax/instructions.html#syntax-instr-atomic-memory +#[inline] +#[cfg_attr(test, assert_instr(memory.atomic.notify))] +#[target_feature(enable = "atomics")] +#[doc(alias("memory.atomic.notify"))] +pub unsafe fn memory_atomic_notify(ptr: *mut i32, waiters: u32) -> u32 { + llvm_atomic_notify(ptr, waiters as i32) as u32 +} |