LEAQ -64(SI)(BX*1), R11
	LEAQ (SI)(BX*1), R13
	VPBROADCASTB  X0, Y1
	PCALIGN $32
avx2_loop:
	VMOVDQU (DI), Y2
	VMOVDQU 32(DI), Y4
	VPCMPEQB Y1, Y2, Y3
	VPCMPEQB Y1, Y4, Y5
	VPMOVMSKB Y3, DX
	VPMOVMSKB Y5, CX
	POPCNTL DX, DX
	POPCNTL CX, CX
	ADDQ DX, R12
	ADDQ CX, R12
	ADDQ $64, DI
	CMPQ DI, R11
	JLE avx2_loop

	// If last block is already processed,
	// skip to the end.
	//

	// Loop is unrolled and uses AVX2.
big_loop_avx2:
	VMOVDQU	(SI), Y2
	VMOVDQU	(DI), Y3
	VMOVDQU	32(SI), Y4
	VMOVDQU	32(DI), Y5
	VPCMPEQB Y2, Y3, Y0
	VPMOVMSKB Y0, AX
	XORL	$0xffffffff, AX
	JNE	diff32_avx2
	VPCMPEQB Y4, Y5, Y6
	VPMOVMSKB Y6, AX
	XORL	$0xffffffff, AX
	JNE	diff64_avx2

	ADDQ	$64, SI
	ADDQ	$64, DI
	SUBQ	$64, R8
	CMPQ	R8, $64
	JB	big_loop_avx2_exit
	JMP	big_loop_avx2

loop32:
	VMOVDQU (DI), Y2
	VPCMPEQB Y1, Y2, Y3
	VPMOVMSKB Y3, SI
	CMPL  SI, $0xffffffff
	JE   success_avx2
	ADDQ $1,DI
	CMPQ DI,DX
	JB loop32
	JMP fail_avx2
_33_to_63:
	LEAQ 1(DI)(DX*1), DX
	SUBQ AX, DX
	VMOVDQU -32(R8)(AX*1), Y0
	VMOVDQU (R8), Y1
loop33to63:
	VMOVDQU (DI), Y2
	VPCMPEQB Y1, Y2, Y3
	VPMOVMSKB Y3, SI
	CMPL  SI, $0xffffffff
	JE   partial_success33to63

	PCALIGN $16
hugeloop_avx2:
	CMPQ	BX, $64
	JB	bigloop_avx2
	VMOVDQU	(SI), Y0
	VMOVDQU	(DI), Y1
	VMOVDQU	32(SI), Y2
	VMOVDQU	32(DI), Y3
	VPCMPEQB	Y1, Y0, Y4
	VPCMPEQB	Y2, Y3, Y5
	VPAND	Y4, Y5, Y6
	VPMOVMSKB Y6, DX
	ADDQ	$64, SI
	ADDQ	$64, DI
	SUBQ	$64, BX
	CMPL	DX, $0xffffffff
	JEQ	hugeloop_avx2
	VZEROUPPER
	XORQ	AX, AX	// return 0
	RET

bigloop_avx2:
	VZEROUPPER

	ADDQ $32, DI
	CMPQ DI, R11
	JLT avx2_loop
	MOVQ R11, DI
	VMOVDQU (DI), Y2
	VPCMPEQB Y1, Y2, Y3
	VPTEST Y3, Y3
	JNZ avx2success
	VZEROUPPER
	MOVQ $-1, (R8)
	RET

avx2success:
	VPMOVMSKB Y3, DX
	BSFL DX, DX
	SUBQ SI, DI
	ADDQ DI, DX
	MOVQ DX, (R8)
	VZEROUPPER

	"VPMINSW",
	"VPMINUB",
	"VPMINUD",
	"VPMINUQ",
	"VPMINUW",
	"VPMOVB2M",
	"VPMOVD2M",
	"VPMOVDB",
	"VPMOVDW",
	"VPMOVM2B",
	"VPMOVM2D",
	"VPMOVM2Q",
	"VPMOVM2W",
	"VPMOVMSKB",
	"VPMOVQ2M",
	"VPMOVQB",
	"VPMOVQD",
	"VPMOVQW",
	"VPMOVSDB",
	"VPMOVSDW",
	"VPMOVSQB",
	"VPMOVSQD",
	"VPMOVSQW",
	"VPMOVSWB",
	"VPMOVSXBD",
	"VPMOVSXBQ",

	VPMINUW Y11, Y15, Y11                   // c442053adb
	VPMOVMSKB X2, DX                        // c4e179d7d2 or c5f9d7d2
	VPMOVMSKB X11, DX                       // c4c179d7d3
	VPMOVMSKB X2, R11                       // c46179d7da or c579d7da
	VPMOVMSKB X11, R11                      // c44179d7db
	VPMOVMSKB Y2, DX                        // c4e17dd7d2 or c5fdd7d2
	VPMOVMSKB Y11, DX                       // c4c17dd7d3