countlines in go asm, v1

countlines_amd64.s

@@ -0,0 +1,86 @@
+// +build amd64,!gccgo,!appengine
+
+#include "textflag.h"
+
+TEXT ·countNewlinesASM(SB),NOSPLIT,$0
+	MOVQ src+0(FP), SI
+	MOVQ len+8(FP), BX
+
+	XORQ AX, AX
+	XORQ DX, DX
+	XORPD X0, X0
+	XORPD X2, X2
+	XORPD X3, X3
+
+	MOVQ $0x0A0A0A0A0A0A0A0A, R10 // prep '\n'
+	PINSRQ $1, R10, X1
+	PINSRQ $0, R10, X1
+
+	CMPQ BX, $16
+	JB tail
+
+	CMPQ BX, $64
+	JB loop
+
+bigloop:
+	VMOVDQU -16(SI)(BX*1),  X11
+	VMOVDQU -32(SI)(BX*1),  X10
+	VMOVDQU -48(SI)(BX*1), X9
+	VMOVDQU -64(SI)(BX*1), X8
+	
+	VPCMPEQB X11, X1, X11
+	VPCMPEQB X10, X1, X10
+	VPCMPEQB X9, X1, X9
+	VPCMPEQB X8, X1, X8
+
+	VPADDB X0, X11, X2
+	VPADDB X2, X10, X2
+	VPADDB X2, X9, X2
+	VPADDB X2, X8, X2
+	PSIGNB X2, X2
+	VPSADBW X2, X0, X2
+	VPADDQ X2, X3, X3
+
+	SUBQ $64, BX
+	JZ ret
+
+	CMPQ BX, $64
+	JAE bigloop
+
+	CMPQ BX, $8
+	JB tail
+
+loop:
+	VMOVDQU -16(SI)(BX*1), X11
+
+	VPCMPEQB X11, X1, X11
+	VPADDB X0, X11, X2
+	PSIGNB X2, X2
+	VPSADBW X2, X0, X2
+	VPADDQ X2, X3, X3
+
+	SUBQ $16, BX
+	JZ ret
+
+	CMPQ BX, $16
+	JAE loop
+
+tail:
+	MOVB -1(SI)(BX*1), DX
+	CMPB DX, $0x0A
+	JNZ next
+
+	INCQ AX
+next:
+
+	SUBQ $1, BX
+	JNZ tail
+
+
+ret:
+	PEXTRQ $0, X3, CX
+	PEXTRQ $1, X3, DX
+	ADDQ CX, AX
+	ADDQ DX, AX
+	MOVQ AX, ret+16(FP)
+	RET