// +build arm64,!gccgo,!appengine

#include "textflag.h"

TEXT ·countNewlinesASM(SB),NOSPLIT,$0
	MOVQ src+0(FP), R1
	MOVQ len+8(FP), R2

	MOVD ZR, R0
  VMOVI $0x0A V23.B16

	CMP $16, R2
	BLT tail

	CMP $64, R2
	BLT loop

bigloop:
	VLD1.P 64(R1), [V16.B16, V17.B16, V18.B16, V19.B16]
	
	VCMEQ V16.B16, V23.B16, V16.B16
	VCMEQ V17.B16, V23.B16, V17.B16
	VCMEQ V18.B16, V23.B16, V18.B16
	VCMEQ V19.B16, V23.B16, V19.B16

	VADD V16.B16, V17.B16, V17.B16
	VADD V18.B16, V19.B16, V19.B16
	VADD V17.B16, V19.B16, V7.B16
	WORD $0x6E20B8E7   // VNEG V7.B16, V7.B16

	VUADDLV V7.B16, V8
	VMOV    V8.H[0], R3
	ADD R3, R0, R0

	SUB $64, R2
	CMP ZR, R2
	BEQ ret

	CMP $64, R2
	BGE bigloop

	CMP $16, R2
	BLT tail

loop:
	VLD1.P  16(R1), [V7.B16]
	WORD $0x6E20B8E7   // VNEG V7.B16, V7.B16
	VUADDLV V7.B16, V8
	VMOV    V8.H[0], R3
	ADD R3, R0, R0

	SUB $16, R2
	CMP ZR, R2
	BEQ ret

	CMP $16, R2
	BGE loop

tail:
	MOVBU 1(R1), R3
	CMP $0x0A, R3
	BNE next

	ADD $1, R0
next:

	SUB $1, R2
	JNZ tail


ret:
	MOVD R0, ret+16(FP)
	RET