MOVV	new+0(FP), R4
	MOVV	old+8(FP), R5
	MOVV	$SYS_sigaltstack, R11
	SYSCALL
	MOVW	$-4096, R5
	BGEU	R5, R4, 2(PC)
	MOVV	R0, 0xf1(R0)	// crash
	RET

// func osyield()
TEXT runtime·osyield(SB),NOSPLIT|NOFRAME,$0
	MOVV	$SYS_sched_yield, R11
	SYSCALL
	RET

// func sched_getaffinity(pid, len uintptr, buf *uintptr) int32
TEXT runtime·sched_getaffinity(SB),NOSPLIT|NOFRAME,$0

	return stdcall(fn)
}

// These must run on the system stack only.

//go:nosplit
func osyield_no_g() {
	stdcall_no_g(_SwitchToThread, 0, 0)
}

//go:nosplit
func osyield() {
	systemstack(func() {
		stdcall0(_SwitchToThread)
	})
}

//go:nosplit
func usleep_no_g(us uint32) {
	timeout := uintptr(us) / 1000 // ms units

	//
	// The critical section on each goroutine here is going to be quite short, so the likelihood
	// that we observe a zero value is high.
	for trace.exitingSyscall.Load() != 0 {
		osyield()
	}

	// Record some initial pieces of information.
	//
	// N.B. This will also emit a status event for this goroutine.
	tl := traceAcquire()

			<-ch1
			ch2 <- 1
		}
	}()
	for i := 0; i < n; i++ {
		ch1 <- 1
		<-ch2
	}
}

func BenchmarkOsYield(b *testing.B) {
	for i := 0; i < b.N; i++ {
		runtime.OsYield()
	}
}

func BenchmarkRunningGoProgram(b *testing.B) {
	tmpdir := b.TempDir()

	src := filepath.Join(tmpdir, "main.go")
	err := os.WriteFile(src, []byte(benchmarkRunningGoProgram), 0666)

	// OK, it will be swept fairly soon.
	for {
		spangen := atomic.Load(&s.sweepgen)
		if spangen == sl.sweepGen || spangen == sl.sweepGen+3 {
			break
		}
		osyield()
	}
}

// sweep frees or collects finalizers for blocks not marked in the mark phase.
// It clears the mark bits in preparation for the next GC round.
// Returns true if the span was returned to heap.