cmd/internal/obj/riscv: add assembly support of Zbc extension

The Zbc extension adds carry-less multiplication instructions for
polynomial arithmetic over GF(2), which is used in cryptographic
algorithms and error-correcting codes. The instructions included
are: clmul, clmulh, and clmulr.

Change-Id: I77a40add1a795c7b90b478dc65835c689e82167a
GitHub-Last-Rev: 53790f0aafa46af2ed24183f58292df7f9fb224a
GitHub-Pull-Request: golang/go#76301
Reviewed-on: https://go-review.googlesource.com/c/go/+/720520
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

5 files changed, 30 insertions, 3 deletions

diff --git a/src/cmd/asm/internal/asm/testdata/riscv64.s b/src/cmd/asm/internal/asm/testdata/riscv64.s
index 1b23680e26..94d1476a6d 100644
--- a/src/cmd/asm/internal/asm/testdata/riscv64.s
+++ b/src/cmd/asm/internal/asm/testdata/riscv64.s
@@ -509,6 +509,14 @@ start:
 	ORCB	X5, X6					// 13d37228
 	REV8	X7, X8					// 13d4836b
 
+	// 28.4.3: Carry-less multiplication (Zbc)
+	CLMUL	X5, X6, X7 				// b313530a
+	CLMUL	X5, X6	 				// 3313530a
+	CLMULH	X5, X6, X7 				// b333530a
+	CLMULH	X5, X6					// 3333530a
+	CLMULR	X5, X6, X7 				// b323530a
+	CLMULR	X5, X6	 				// 3323530a
+
 	// 28.4.4: Single-bit Instructions (Zbs)
 	BCLR	X23, X24, X25				// b31c7c49
 	BCLR	$63, X24				// 131cfc4b
diff --git a/src/cmd/internal/obj/riscv/anames.go b/src/cmd/internal/obj/riscv/anames.go
index 6c48e2f7de..1f777dd195 100644
--- a/src/cmd/internal/obj/riscv/anames.go
+++ b/src/cmd/internal/obj/riscv/anames.go
@@ -263,6 +263,9 @@ var Anames = []string{
 	"RORW",
 	"ORCB",
 	"REV8",
+	"CLMUL",
+	"CLMULH",
+	"CLMULR",
 	"BCLR",
 	"BCLRI",
 	"BEXT",
diff --git a/src/cmd/internal/obj/riscv/cpu.go b/src/cmd/internal/obj/riscv/cpu.go
index a91395dd38..64a1a02a53 100644
--- a/src/cmd/internal/obj/riscv/cpu.go
+++ b/src/cmd/internal/obj/riscv/cpu.go
@@ -672,7 +672,7 @@ const (
 	ASEXTH
 	AZEXTH
 
-	// 28.4.3: Bitwise Rotation (Zbb)
+	// 28.4.2: Bitwise Rotation (Zbb)
 	AROL
 	AROLW
 	AROR
@@ -682,6 +682,11 @@ const (
 	AORCB
 	AREV8
 
+	// 28.4.3: Carry-less multiplication (Zbc)
+	ACLMUL
+	ACLMULH
+	ACLMULR
+
 	// 28.4.4: Single-bit Instructions (Zbs)
 	ABCLR
 	ABCLRI
diff --git a/src/cmd/internal/obj/riscv/inst.go b/src/cmd/internal/obj/riscv/inst.go
index a5b3acdb18..a41b35d5a3 100644
--- a/src/cmd/internal/obj/riscv/inst.go
+++ b/src/cmd/internal/obj/riscv/inst.go
@@ -1,4 +1,4 @@
-// Code generated by ./parse.py -go rv64_a rv64_c rv64_d rv64_f rv64_i rv64_m rv64_q rv64_zba rv64_zbb rv64_zbs rv_a rv_c rv_c_d rv_d rv_f rv_i rv_m rv_q rv_s rv_system rv_v rv_zba rv_zbb rv_zbs rv_zicond rv_zicsr; DO NOT EDIT.
+// Code generated by ./parse.py -go rv64_a rv64_c rv64_d rv64_f rv64_i rv64_m rv64_q rv64_zba rv64_zbb rv64_zbs rv_a rv_c rv_c_d rv_d rv_f rv_i rv_m rv_q rv_s rv_system rv_v rv_zba rv_zbb rv_zbc rv_zbs rv_zicond rv_zicsr; DO NOT EDIT.
 package riscv
 
 import "cmd/internal/obj"
@@ -170,6 +170,12 @@ func encode(a obj.As) *inst {
 		return &inst{0x2, 0x4, 0x1, 0x0, 0, 0x0}
 	case ACXOR:
 		return &inst{0x21, 0x0, 0x1, 0x0, 0, 0x0}
+	case ACLMUL:
+		return &inst{0x33, 0x1, 0x0, 0x0, 160, 0x5}
+	case ACLMULH:
+		return &inst{0x33, 0x3, 0x0, 0x0, 160, 0x5}
+	case ACLMULR:
+		return &inst{0x33, 0x2, 0x0, 0x0, 160, 0x5}
 	case ACLZ:
 		return &inst{0x13, 0x1, 0x0, 0x0, 1536, 0x30}
 	case ACLZW:
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index 5bab0ff419..a55c6faf65 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -2640,7 +2640,7 @@ var instructions = [ALAST & obj.AMask]instructionData{
 	AXNOR & obj.AMask:  {enc: rIIIEncoding, ternary: true},
 	AZEXTH & obj.AMask: {enc: rIIEncoding},
 
-	// 28.4.3: Bitwise Rotation (Zbb)
+	// 28.4.2: Bitwise Rotation (Zbb)
 	AROL & obj.AMask:   {enc: rIIIEncoding, ternary: true},
 	AROLW & obj.AMask:  {enc: rIIIEncoding, ternary: true},
 	AROR & obj.AMask:   {enc: rIIIEncoding, immForm: ARORI, ternary: true},
@@ -2650,6 +2650,11 @@ var instructions = [ALAST & obj.AMask]instructionData{
 	AORCB & obj.AMask:  {enc: rIIEncoding},
 	AREV8 & obj.AMask:  {enc: rIIEncoding},
 
+	// 28.4.3: Carry-less Multiplication (Zbc)
+	ACLMUL & obj.AMask:  {enc: rIIIEncoding, ternary: true},
+	ACLMULH & obj.AMask: {enc: rIIIEncoding, ternary: true},
+	ACLMULR & obj.AMask: {enc: rIIIEncoding, ternary: true},
+
 	// 28.4.4: Single-bit Instructions (Zbs)
 	ABCLR & obj.AMask:  {enc: rIIIEncoding, immForm: ABCLRI, ternary: true},
 	ABCLRI & obj.AMask: {enc: iIIEncoding, ternary: true},