i := 0
	for n != 0 {
		// amd64/v1,amd64/v2:"BSFL",-"BTSQ"
		// amd64/v3:"TZCNTL"
		i += bits.TrailingZeros32(n)
		n &= n - 1
	}
	return i
}

func IterateBits16(n uint16) int {
	i := 0
	for n != 0 {
		// amd64/v1,amd64/v2:"BSFL",-"BTSL"
		// amd64/v3:"TZCNTL"
		// arm64:"RBITW","CLZW",-"ORR"
		i += bits.TrailingZeros16(n)
		n &= n - 1
	}
	return i
}

(Ctz8  x) => (BSFL (ORLconst <typ.UInt32> [1<<8 ] x))

(Ctz64NonZero x) && buildcfg.GOAMD64 >= 3 => (TZCNTQ x)
(Ctz32NonZero x) && buildcfg.GOAMD64 >= 3 => (TZCNTL x)
(Ctz16NonZero x) && buildcfg.GOAMD64 >= 3 => (TZCNTL x)
(Ctz8NonZero  x) && buildcfg.GOAMD64 >= 3 => (TZCNTL x)
(Ctz64NonZero x) && buildcfg.GOAMD64 <  3 => (Select0 (BSFQ x))
(Ctz32NonZero x) && buildcfg.GOAMD64 <  3 => (BSFL x)

		// count the number of trailing zero bits, prefer TZCNTQ over BSFQ, as TZCNTQ(0)==64
		// and BSFQ(0) is undefined. Same for TZCNTL(0)==32
		{name: "TZCNTQ", argLength: 1, reg: gp11, asm: "TZCNTQ", clobberFlags: true},
		{name: "TZCNTL", argLength: 1, reg: gp11, asm: "TZCNTL", clobberFlags: true},

		// CPUID feature: LZCNT.
		// count the number of leading zero bits.

// systems by fcntl_linux_32bit.go to be SYS_FCNTL64.
var fcntl64Syscall uintptr = SYS_FCNTL

func fcntl(fd int, cmd, arg int) (int, error) {
	valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg))
	var err error
	if errno != 0 {
		err = errno
	}
	return int(valptr), err
}

// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
func FcntlInt(fd uintptr, cmd, arg int) (int, error) {

		v.AddArg(v0)
		return true
	}
}
func rewriteValueAMD64_OpCtz16NonZero(v *Value) bool {
	v_0 := v.Args[0]
	// match: (Ctz16NonZero x)
	// cond: buildcfg.GOAMD64 >= 3
	// result: (TZCNTL x)
	for {
		x := v_0
		if !(buildcfg.GOAMD64 >= 3) {
			break
		}
		v.reset(OpAMD64TZCNTL)
		v.AddArg(x)
		return true
	}
	// match: (Ctz16NonZero x)

// descriptors.
func forkExecPipe(p []int) error {
	err := Pipe(p)
	if err != nil {
		return err
	}
	_, err = fcntl(p[0], F_SETFD, FD_CLOEXEC)
	if err != nil {
		return err
	}
	_, err = fcntl(p[1], F_SETFD, FD_CLOEXEC)
	return err
}

func acquireForkLock() {
	ForkLock.Lock()
}

func releaseForkLock() {
	ForkLock.Unlock()

// license that can be found in the LICENSE file.

//go:build (linux && 386) || (linux && arm) || (linux && mips) || (linux && mipsle) || (linux && ppc)

package unix

func init() {
	// On 32-bit Linux systems, the fcntl syscall that matches Go's
	// Flock_t type is SYS_FCNTL64, not SYS_FCNTL.
	fcntl64Syscall = SYS_FCNTL64

// license that can be found in the LICENSE file.

//go:build darwin || dragonfly || freebsd || netbsd || openbsd

package syscall

import "unsafe"

// FcntlFlock performs a fcntl syscall for the [F_GETLK], [F_SETLK] or [F_SETLKW] command.
func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
	_, err := fcntlPtr(int(fd), cmd, unsafe.Pointer(lk))
	return err

// license that can be found in the LICENSE file.

//go:build (linux && 386) || (linux && arm) || (linux && mips) || (linux && mipsle)

package syscall

func init() {
	// On 32-bit Linux systems, the fcntl syscall that matches Go's
	// Flock_t type is SYS_FCNTL64, not SYS_FCNTL.
	fcntl64Syscall = SYS_FCNTL64

// used by internal/poll
//go:linkname fdopendir

// used by internal/syscall/unix
//go:linkname unlinkat
//go:linkname openat
//go:linkname fstatat

// used by cmd/link
//go:linkname msync