cmd/asm: add support for loong64 CRC32 instructions

This patch is a copy of CL 478595.
Co-authored-by: WANG Xuerui <git@xen0n.name>

Change-Id: Ifb6e8183c83a5dfe5dec84e173a74d5de62692a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/623875
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/asm/internal/asm/testdata/loong64enc1.s

@@ -208,6 +208,16 @@ lable2:
 	MASKEQZ	R4, R5, R6		// a6101300
 	MASKNEZ	R4, R5, R6		// a6901300
 
+	// CRC32
+	CRCWBW	R4, R5, R6		// a6102400
+	CRCWHW	R4, R5, R6		// a6902400
+	CRCWWW	R4, R5, R6		// a6102500
+	CRCWVW	R4, R5, R6		// a6902500
+	CRCCWBW	R4, R5, R6		// a6102600
+	CRCCWHW	R4, R5, R6		// a6902600
+	CRCCWWW	R4, R5, R6		// a6102700
+	CRCCWVW	R4, R5, R6		// a6902700
+
 	MOVFD	F4, F5			// 85241901
 	MOVDF	F4, F5			// 85181901
 	MOVWF	F4, F5			// 85101d01

src/cmd/internal/obj/loong64/a.out.go

@@ -477,6 +477,16 @@ const (
 	ABSTRPICKW
 	ABSTRPICKV
 
+	// 2.2.9. CRC Check Instructions
+	ACRCWBW
+	ACRCWHW
+	ACRCWWW
+	ACRCWVW
+	ACRCCWBW
+	ACRCCWHW
+	ACRCCWWW
+	ACRCCWVW
+
 	// 2.2.10. Other Miscellaneous Instructions
 	ARDTIMELW
 	ARDTIMEHW

src/cmd/internal/obj/loong64/anames.go

@@ -199,6 +199,14 @@ var Anames = []string{
 	"BSTRINSV",
 	"BSTRPICKW",
 	"BSTRPICKV",
+	"CRCWBW",
+	"CRCWHW",
+	"CRCWWW",
+	"CRCWVW",
+	"CRCCWBW",
+	"CRCCWHW",
+	"CRCCWWW",
+	"CRCCWVW",
 	"RDTIMELW",
 	"RDTIMEHW",
 	"RDTIMED",

src/cmd/internal/obj/loong64/asm.go

@@ -1234,6 +1234,14 @@ func buildop(ctxt *obj.Link) {
 
 		case AMASKEQZ:
 			opset(AMASKNEZ, r0)
+			opset(ACRCWBW, r0)
+			opset(ACRCWHW, r0)
+			opset(ACRCWWW, r0)
+			opset(ACRCWVW, r0)
+			opset(ACRCCWBW, r0)
+			opset(ACRCCWHW, r0)
+			opset(ACRCCWWW, r0)
+			opset(ACRCCWVW, r0)
 
 		case ANOOP:
 			opset(obj.AUNDEF, r0)
@@ -1949,7 +1957,22 @@ func (c *ctxt0) oprrr(a obj.As) uint32 {
 		return 0x45 << 15 // mod.d
 	case AREMVU:
 		return 0x47 << 15 // mod.du
-
+	case ACRCWBW:
+		return 0x48 << 15 // crc.w.b.w
+	case ACRCWHW:
+		return 0x49 << 15 // crc.w.h.w
+	case ACRCWWW:
+		return 0x4a << 15 // crc.w.w.w
+	case ACRCWVW:
+		return 0x4b << 15 // crc.w.d.w
+	case ACRCCWBW:
+		return 0x4c << 15 // crcc.w.b.w
+	case ACRCCWHW:
+		return 0x4d << 15 // crcc.w.h.w
+	case ACRCCWWW:
+		return 0x4e << 15 // crcc.w.w.w
+	case ACRCCWVW:
+		return 0x4f << 15 // crcc.w.d.w
 	case AJMP:
 		return 0x13 << 26 // jirl r0, rj, 0
 	case AJAL: