//go:linkname subVV
//go:noescape
func subVV(z, x, y []Word) (c Word)

// addVW should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/remyoudompheng/bigfft
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname addVW
//go:noescape
func addVW(z, x []Word, y Word) (c Word)

// subVW should be an internal detail,

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

//go:build !math_big_pure_go

#include "textflag.h"

TEXT ·addVV(SB),NOSPLIT,$0
	JMP ·addVV_g(SB)

TEXT ·subVV(SB),NOSPLIT,$0
	JMP ·subVV_g(SB)

TEXT ·addVW(SB),NOSPLIT,$0
	JMP ·addVW_g(SB)

TEXT ·subVW(SB),NOSPLIT,$0
	JMP ·subVW_g(SB)

TEXT ·shlVU(SB),NOSPLIT,$0
	JMP ·shlVU_g(SB)

TEXT ·shrVU(SB),NOSPLIT,$0
	JMP ·shrVU_g(SB)

// arithmetic operations on vectors implemented in arith.go.

TEXT ·addVV(SB),NOSPLIT,$0
	JMP	·addVV_g(SB)

TEXT ·subVV(SB),NOSPLIT,$0
	JMP	·subVV_g(SB)

TEXT ·addVW(SB),NOSPLIT,$0
	JMP	·addVW_g(SB)

TEXT ·subVW(SB),NOSPLIT,$0
	JMP	·subVW_g(SB)

TEXT ·shlVU(SB),NOSPLIT,$0
	JMP	·shlVU_g(SB)

TEXT ·shrVU(SB),NOSPLIT,$0
	JMP	·shrVU_g(SB)

		y := rndW()
		z := make(nat, n)
		arg := argVW{z, x, y, 0}
		testFunVWext(t, "addVW, random inputs", addVW, addVW_g, arg)
		testFunVWext(t, "subVW, random inputs", subVW, subVW_g, arg)

		// vector of random numbers, but make 'x' and 'z' share storage
		arg = argVW{x, x, y, 0}
		testFunVWext(t, "addVW, random inputs, sharing storage", addVW, addVW_g, arg)
		testFunVWext(t, "subVW, random inputs, sharing storage", subVW, subVW_g, arg)

// arithmetic operations on vectors implemented in arith.go.

TEXT ·addVV(SB),NOSPLIT,$0
	JMP ·addVV_g(SB)

TEXT ·subVV(SB),NOSPLIT,$0
	JMP ·subVV_g(SB)

TEXT ·addVW(SB),NOSPLIT,$0
	JMP ·addVW_g(SB)

TEXT ·subVW(SB),NOSPLIT,$0
	JMP ·subVW_g(SB)

TEXT ·shlVU(SB),NOSPLIT,$0
	JMP ·shlVU_g(SB)

TEXT ·shrVU(SB),NOSPLIT,$0
	JMP ·shrVU_g(SB)

// arithmetic operations on vectors implemented in arith.go.

TEXT ·addVV(SB),NOSPLIT,$0
	JMP ·addVV_g(SB)

TEXT ·subVV(SB),NOSPLIT,$0
	JMP ·subVV_g(SB)

TEXT ·addVW(SB),NOSPLIT,$0
	JMP ·addVW_g(SB)

TEXT ·subVW(SB),NOSPLIT,$0
	JMP ·subVW_g(SB)

TEXT ·shlVU(SB),NOSPLIT,$0
	JMP ·shlVU_g(SB)

TEXT ·shrVU(SB),NOSPLIT,$0
	JMP ·shrVU_g(SB)

// arithmetic operations on vectors implemented in arith.go.

TEXT ·addVV(SB),NOSPLIT,$0
	JMP ·addVV_g(SB)

TEXT ·subVV(SB),NOSPLIT,$0
	JMP ·subVV_g(SB)

TEXT ·addVW(SB),NOSPLIT,$0
	JMP ·addVW_g(SB)

TEXT ·subVW(SB),NOSPLIT,$0
	JMP ·subVW_g(SB)

TEXT ·shlVU(SB),NOSPLIT,$0
	JMP ·shlVU_g(SB)

TEXT ·shrVU(SB),NOSPLIT,$0
	JMP ·shrVU_g(SB)

//go:build math_big_pure_go

package big

func addVV(z, x, y []Word) (c Word) {
	return addVV_g(z, x, y)
}

func subVV(z, x, y []Word) (c Word) {
	return subVV_g(z, x, y)
}

func addVW(z, x []Word, y Word) (c Word) {
	// TODO: remove indirect function call when golang.org/issue/30548 is fixed
	fn := addVW_g
	if len(z) > 32 {
		fn = addVWlarge
	}
	return fn(z, x, y)
}

	STP	(R10, R11), -16(R3);	\
	SUB	$4, counter;

// do one iteration of copy in addVW/subVW
#define vwOneIterCopy(counter, exit)			\
	CBZ	counter, exit;				\
	LDP.P	32(R1), (R4, R5);			\
	LDP	-16(R1), (R6, R7);			\
	STP.P	(R4, R5), 32(R3);			\
	STP	(R6, R7), -16(R3);			\
	SUB	$4, counter;

// func addVW(z, x []Word, y Word) (c Word)
// The 'large' branch handles large 'z'. It checks the carry flag on every iteration

	SBBL (CX)(BX*4), AX
	SBBL DX, DX		// save CF
	MOVL AX, (DI)(BX*4)
	ADDL $1, BX		// i++

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)