fix register indices

Author: mhr3

x86/x86asm/decode.go

@@ -1276,7 +1276,8 @@ Decode:
 			narg++
 		case xArgRM8, xArgRM16, xArgRM32, xArgRM64, xArgR32M16, xArgR32M8, xArgR64M16,
 			xArgMmM32, xArgMmM64, xArgMm2M64,
-			xArgXmm2M16, xArgXmm2M32, xArgXmm2M64, xArgXmm2M128, xArgXmmM32, xArgXmmM64, xArgXmmM128,
+			xArgXmmM32, xArgXmmM64, xArgXmmM128,
+			xArgXmm2M8, xArgXmm2M16, xArgXmm2M32, xArgXmm2M64, xArgXmm2M128,
 			xArgYmm2M256:
 			if haveMem {
 				inst.Args[narg] = mem
@@ -1298,8 +1299,8 @@ Decode:
 						index -= 4
 						base = SPB
 					}
-				case xArgYmm2M256:
-					if vex == 0xC4 && inst.Prefix[vexIndex+1]&0x40 == 0x40 {
+				case xArgXmm2M8, xArgXmm2M16, xArgXmm2M32, xArgXmm2M64, xArgXmm2M128, xArgYmm2M256:
+					if vex == 0xC4 && inst.Prefix[vexIndex+1]&0x20 == 0 {
 						index += 8
 					}
 				}
@@ -1692,6 +1693,7 @@ var baseReg = [...]Reg{
 	xArgXmm2M16:    X0,
 	xArgXmm2M32:    X0,
 	xArgXmm2M64:    X0,
+	xArgXmm2M8:     X0,
 	xArgXmm:        X0,
 	xArgXmmV:       X0,
 	xArgXmmM128:    X0,

x86/x86asm/testdata/decode.txt

@@ -6761,6 +6761,15 @@ c4227d2a0c36|6677885f5f5f5f5f5f5f	64	gnu	vmovntdqa (%rsi,%r14,1),%ymm9
 c57d7ff7|44556677885f5f5f5f5f5f5f	64	intel	vmovdqa ymm7, ymm14
 c57d7ff7|44556677885f5f5f5f5f5f5f	64	plan9	VMOVDQA Y14, Y7
 c57d7ff7|44556677885f5f5f5f5f5f5f	64	gnu	vmovdqa %ymm14,%ymm7
+c4e27d791500000000|5f5f5f5f5f5f5f	64	intel	vpbroadcastw ymm2, word ptr [rip]
+c4e27d791500000000|5f5f5f5f5f5f5f	64	plan9	VPBROADCASTW 0(IP), Y2
+c4e27d791500000000|5f5f5f5f5f5f5f	64	gnu	vpbroadcastww (%rip),%ymm2
+c4e27d78c8|556677885f5f5f5f5f5f5f	64	intel	vpbroadcastb ymm1, xmm0
+c4e27d78c8|556677885f5f5f5f5f5f5f	64	plan9	VPBROADCASTB X0, Y1
+c4e27d78c8|556677885f5f5f5f5f5f5f	64	gnu	vpbroadcastb %xmm0,%ymm1
+c441305ec2|556677885f5f5f5f5f5f5f	64	intel	vdivps xmm8, xmm9, xmm10
+c441305ec2|556677885f5f5f5f5f5f5f	64	plan9	VDIVPS X10, X9, X8
+c441305ec2|556677885f5f5f5f5f5f5f	64	gnu	vdivps %xmm10,%xmm9,%xmm8
 c5f5efe2|44556677885f5f5f5f5f5f5f	64	intel	vpxor ymm4, ymm1, ymm2
 c5f5efe2|44556677885f5f5f5f5f5f5f	64	plan9	VPXOR Y2, Y1, Y4
 c5f5efe2|44556677885f5f5f5f5f5f5f	64	gnu	vpxor %ymm2,%ymm1,%ymm4