const bufSize = 256

// xorKeyStreamVX is an assembly implementation of XORKeyStream. It must only
// be called when the vector facility is available. Implementation in asm_s390x.s.
//
//go:noescape
func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32)

func (c *Cipher) xorKeyStreamBlocks(dst, src []byte) {
	if cpu.S390X.HasVX {
		xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter)
	} else {

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

//go:build gc && !purego

package chacha20

const bufSize = 256

//go:noescape
func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32)

func (c *Cipher) xorKeyStreamBlocks(dst, src []byte) {
	xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter)

	VMRLF t, u, b \ // b = {a[1], b[1], c[1], d[1]}
	VMRHF v, w, c \ // c = {a[2], b[2], c[2], d[2]}
	VMRLF v, w, d // d = {a[3], b[3], c[3], d[3]}

// func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32)
TEXT ·xorKeyStreamVX(SB), NOSPLIT, $0
	MOVD $·constants<>(SB), R1
	MOVD dst+0(FP), R2         // R2=&dst[0]
	LMG  src+24(FP), R3, R4    // R3=&src[0] R4=len(src)

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

//go:build gc && !purego

#include "textflag.h"

#define NUM_ROUNDS 10

// func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32)
TEXT ·xorKeyStreamVX(SB), NOSPLIT, $0
	MOVD	dst+0(FP), R1
	MOVD	src+24(FP), R2
	MOVD	src_len+32(FP), R3
	MOVD	key+48(FP), R4
	MOVD	nonce+56(FP), R6
	MOVD	counter+64(FP), R7