func Add(x, y, ci uint) (r, co uint) {
	// arm64:"ADDS","ADCS","ADC",-"ADD\t",-"CMP"
	// amd64:"NEGL","ADCQ","SBBQ","NEGQ"
	// ppc64x: "ADDC", "ADDE", "ADDZE"
	// s390x:"ADDE","ADDC\t[$]-1,"
	// riscv64: "ADD","SLTU"
	return bits.Add(x, y, ci)
}

func AddC(x, ci uint) (r, co uint) {
	// arm64:"ADDS","ADCS","ADC",-"ADD\t",-"CMP"
	// amd64:"NEGL","ADCQ","SBBQ","NEGQ"
	// loong64: "ADDV", "SGTU"
	// ppc64x: "ADDC", "ADDE", "ADDZE"

E2:	CMPL BX, BP		// i < n
	JL L2

	NEGL DX
	MOVL DX, c+36(FP)
	RET


// func addVW(z, x []Word, y Word) (c Word)
TEXT ·addVW(SB),NOSPLIT,$0
	MOVL z+0(FP), DI
	MOVL x+12(FP), SI
	MOVL y+24(FP), AX	// c = y
	MOVL z_len+4(FP), BP
	MOVL $0, BX		// i = 0
	JMP E3

L3:	ADDL (SI)(BX*4), AX
	MOVL AX, (DI)(BX*4)
	SBBL AX, AX		// save CF
	NEGL AX
	ADDL $1, BX		// i++

E3:	CMPL BX, BP		// i < n

#define SYS_pipe2 		542
#define SYS_kevent		560

TEXT runtime·sys_umtx_op(SB),NOSPLIT,$-4
	MOVL	$SYS__umtx_op, AX
	INT	$0x80
	JAE	2(PC)
	NEGL	AX
	MOVL	AX, ret+20(FP)
	RET

TEXT runtime·thr_new(SB),NOSPLIT,$-4
	MOVL	$SYS_thr_new, AX
	INT	$0x80
	JAE	2(PC)
	NEGL	AX
	MOVL	AX, ret+8(FP)
	RET

// Called by OS using C ABI.
TEXT runtime·thr_start(SB),NOSPLIT,$0

	MOVL	a1+4(FP), BX
	MOVL	a2+8(FP), CX
	MOVL	a3+12(FP), DX
	POPL	SI // preserve return address
	INVOKE_SYSCALL
	PUSHL	SI
	CMPL	AX, $0xfffff001
	JLS	ok
	MOVL	$-1, r1+16(FP)
	NEGL	AX
	MOVL	AX, err+20(FP)
	RET
ok:
	MOVL	AX, r1+16(FP)
	MOVL	$0, err+20(FP)
	RET

// func rawSyscallNoError(trap uintptr, a1, a2, a3 uintptr) (r1, r2 uintptr);
TEXT ·rawSyscallNoError(SB),NOSPLIT,$0-24

	MOVSL				// arg 6 - newlen
	MOVL	$SYS___sysctl, AX
	INT	$0x80
	JAE	4(PC)
	NEGL	AX
	MOVL	AX, ret+24(FP)
	RET
	MOVL	$0, AX
	MOVL	AX, ret+24(FP)
	RET

GLOBL runtime·tlsoffset(SB),NOPTR,$4

// int32 runtime·kqueue(void)
TEXT runtime·kqueue(SB),NOSPLIT,$0
	MOVL	$SYS_kqueue, AX
	INT	$0x80
	JAE	2(PC)
	NEGL	AX
	MOVL	AX, ret+0(FP)
	RET

	MOVL	a2+8(FP), CX
	MOVL	a3+12(FP), DX
	MOVL	a4+16(FP), SI
	MOVL	a5+20(FP), DI
	MOVL	a6+24(FP), BP
	INVOKE_SYSCALL
	CMPL	AX, $0xfffff001
	JLS	ok
	MOVL	$-1, r1+28(FP)
	MOVL	$0, r2+32(FP)
	NEGL	AX
	MOVL	AX, errno+36(FP)
	RET
ok:
	MOVL	AX, r1+28(FP)
	MOVL	DX, r2+32(FP)
	MOVL	$0, errno+36(FP)

TEXT ·addMulVVW2048(SB), $0-16
	MOVL	$64, BX
	JMP		addMulVVWx(SB)

TEXT addMulVVWx(SB), NOFRAME|NOSPLIT, $0
	MOVL z+0(FP), DI
	MOVL x+4(FP), SI
	MOVL y+8(FP), BP
	LEAL (DI)(BX*4), DI
	LEAL (SI)(BX*4), SI
	NEGL BX			// i = -n
	MOVL $0, CX		// c = 0
	JMP E6

L6:	MOVL (SI)(BX*4), AX
	MULL BP
	ADDL CX, AX
	ADCL $0, DX
	ADDL AX, (DI)(BX*4)
	ADCL $0, DX
	MOVL DX, CX
	ADDL $1, BX		// i++

	CALL	libc_errno(SB)
	MOVL	(AX), AX		// errno
	NEGL	AX			// caller expects negative errno value
noerr:
	RET

TEXT runtime·write_trampoline(SB),NOSPLIT,$0
	MOVQ	8(DI), SI		// arg 2 buf
	MOVL	16(DI), DX		// arg 3 count
	MOVL	0(DI), DI		// arg 1 fd
	CALL	libc_write(SB)
	TESTL	AX, AX
	JGE	noerr
	CALL	libc_errno(SB)
	MOVL	(AX), AX		// errno
	NEGL	AX			// caller expects negative errno value
noerr:
	RET

alle
con
col
coi
da
dal
dallo
dai
dagli
dall
dagl
dalla
dalle
di
del
dello
dei
degli
dell
degl
della
delle
in
nel
nello
nei
negli
nell
negl
nella
nelle
su
sul
sullo
sui
sugli
sull
sugl
sulla
sulle
per
tra
contro
io
tu
lui
lei
noi
voi
loro
mio
mia
miei
mie
tuo
tua
tuoi

	SHRL	CX, BX	// move a's bit to bottom
	ANDL	$1, BX	// mask bit
	LEAL	-1(BX*2), BX // 1/0 => +1/-1
	MOVL	BX, (AX)
	RET

	// 0-3 bytes in common
small:
	LEAL	(BP*8), CX
	NEGL	CX
	JEQ	allsame

	// load si
	CMPB	SI, $0xfc
	JA	si_high
	MOVL	(SI), SI
	JMP	si_finish
si_high:
	MOVL	-4(SI)(BP*1), SI
	SHRL	CX, SI
si_finish:
	SHLL	CX, SI

	// same for di