// authentication.
func UnixCredentials(ucred *Ucred) []byte {
	b := make([]byte, CmsgSpace(SizeofUcred))
	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
	h.Level = SOL_SOCKET
	h.Type = SCM_CREDENTIALS
	h.SetLen(CmsgLen(SizeofUcred))
	*(*Ucred)(h.data(0)) = *ucred
	return b
}

// ParseUnixCredentials decodes a socket control message that contains
// credentials in a Ucred structure. To receive such a message, the

	MOVBU	(R4), R8
	BNE	R7, R8, loop

	SUBV	R6, R4		// remove base
	RET

notfound:
	MOVV	$-1, R4
	RET

TEXT ·IndexByteString<ABIInternal>(SB),NOSPLIT,$0-32
	// R4 = s_base
	// R5 = s_len
	// R6 = byte to find
	MOVV	R4, R7		// store base for later
	ADDV	R4, R5		// end
	ADDV	$-1, R4

	PCALIGN	$16
loop:
	ADDV	$1, R4
	BEQ	R4, R5, notfound
	MOVBU	(R4), R8
	BNE	R6, R8, loop

	}
	return n, nil
}

// Atoi is equivalent to ParseInt(s, 10, 0), converted to type int.
func Atoi(s string) (int, error) {
	const fnAtoi = "Atoi"

	sLen := len(s)
	if intSize == 32 && (0 < sLen && sLen < 10) ||
		intSize == 64 && (0 < sLen && sLen < 19) {
		// Fast path for small integers that fit int type.
		s0 := s
		if s[0] == '-' || s[0] == '+' {
			s = s[1:]
			if len(s) < 1 {