Odin/core/atomic.odin

// TODO(bill): Use assembly instead here to implement atomics
// Inline vs external file?

#import win32 "sys/windows.odin" when ODIN_OS == "windows";
_ := compile_assert(ODIN_ARCH == "amd64"); // TODO(bill): x86 version


yield_thread :: proc() { win32._mm_pause(); }
mfence       :: proc() { win32.ReadWriteBarrier(); }
sfence       :: proc() { win32.WriteBarrier(); }
lfence       :: proc() { win32.ReadBarrier(); }


load :: proc(a: ^i32) -> i32 {
	return a^;
}
store :: proc(a: ^i32, value: i32) {
	a^ = value;
}
compare_exchange :: proc(a: ^i32, expected, desired: i32) -> i32 {
	return win32.InterlockedCompareExchange(a, desired, expected);
}
exchanged :: proc(a: ^i32, desired: i32) -> i32 {
	return win32.InterlockedExchange(a, desired);
}
fetch_add :: proc(a: ^i32, operand: i32) -> i32 {
	return win32.InterlockedExchangeAdd(a, operand);

}
fetch_and :: proc(a: ^i32, operand: i32) -> i32 {
	return win32.InterlockedAnd(a, operand);
}
fetch_or :: proc(a: ^i32, operand: i32) -> i32 {
	return win32.InterlockedOr(a, operand);
}
spin_lock :: proc(a: ^i32, time_out: int) -> bool { // NOTE(bill) time_out = -1 as default
	old_value := compare_exchange(a, 1, 0);
	counter := 0;
	for old_value != 0 && (time_out < 0 || counter < time_out) {
		counter += 1;
		yield_thread();
		old_value = compare_exchange(a, 1, 0);
		mfence();
	}
	return old_value == 0;
}
spin_unlock :: proc(a: ^i32) {
	store(a, 0);
	mfence();
}
try_acquire_lock :: proc(a: ^i32) -> bool {
	yield_thread();
	old_value := compare_exchange(a, 1, 0);
	mfence();
	return old_value == 0;
}


load :: proc(a: ^i64) -> i64 {
	return a^;
}
store :: proc(a: ^i64, value: i64) {
	a^ = value;
}
compare_exchange :: proc(a: ^i64, expected, desired: i64) -> i64 {
	return win32.InterlockedCompareExchange64(a, desired, expected);
}
exchanged :: proc(a: ^i64, desired: i64) -> i64 {
	return win32.InterlockedExchange64(a, desired);
}
fetch_add :: proc(a: ^i64, operand: i64) -> i64 {
	return win32.InterlockedExchangeAdd64(a, operand);
}
fetch_and :: proc(a: ^i64, operand: i64) -> i64 {
	return win32.InterlockedAnd64(a, operand);
}
fetch_or :: proc(a: ^i64, operand: i64) -> i64 {
	return win32.InterlockedOr64(a, operand);
}
spin_lock :: proc(a: ^i64, time_out: int) -> bool { // NOTE(bill) time_out = -1 as default
	old_value := compare_exchange(a, 1, 0);
	counter := 0;
	for old_value != 0 && (time_out < 0 || counter < time_out) {
		counter += 1;
		yield_thread();
		old_value = compare_exchange(a, 1, 0);
		mfence();
	}
	return old_value == 0;
}
spin_unlock :: proc(a: ^i64) {
	store(a, 0);
	mfence();
}
try_acquire_lock :: proc(a: ^i64) -> bool {
	yield_thread();
	old_value := compare_exchange(a, 1, 0);
	mfence();
	return old_value == 0;
}