cmd/internal/obj/loong64: add support for instructions BSTRPICK.{W/D} and BSTRINS.{W/D}

Go asm syntax:
	BSTRPICK{W/V}	$msb, RJ, $lsb, RD
	BSTRINS{W/V}	$msb, RJ, $lsb, RD

Equivalent platform assembler syntax:
	bstrpick.{w/d}	rd, rj, $msb, $lsb
	bstrins.{w/d}	rd, rj, $msb, $lsb

Ref: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html

Change-Id: I8b89b766ed22a96da7d8d5b2b2873382a49208de
Reviewed-on: https://go-review.googlesource.com/c/go/+/604735
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

4 files changed, 71 insertions, 1 deletions

diff --git a/src/cmd/internal/obj/loong64/a.out.go b/src/cmd/internal/obj/loong64/a.out.go
index d1cd35b878..7c20df3b2d 100644
--- a/src/cmd/internal/obj/loong64/a.out.go
+++ b/src/cmd/internal/obj/loong64/a.out.go
@@ -435,6 +435,14 @@ const (
 	AAMMINDBWU
 	AAMMINDBVU
 
+	// 2.2.3.8
+	ABSTRINSW
+	ABSTRINSV
+
+	// 2.2.3.9
+	ABSTRPICKW
+	ABSTRPICKV
+
 	// 2.2.10. Other Miscellaneous Instructions
 	ARDTIMELW
 	ARDTIMEHW
diff --git a/src/cmd/internal/obj/loong64/anames.go b/src/cmd/internal/obj/loong64/anames.go
index 0749db8312..ed3d5b25ce 100644
--- a/src/cmd/internal/obj/loong64/anames.go
+++ b/src/cmd/internal/obj/loong64/anames.go
@@ -175,6 +175,10 @@ var Anames = []string{
 	"AMMAXDBVU",
 	"AMMINDBWU",
 	"AMMINDBVU",
+	"BSTRINSW",
+	"BSTRINSV",
+	"BSTRPICKW",
+	"BSTRPICKV",
 	"RDTIMELW",
 	"RDTIMEHW",
 	"RDTIMED",
diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index 52fe7b2c89..d78e594fc9 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -217,6 +217,10 @@ var optab = []Optab{
 	{ASLLV, C_SCON, C_REG, C_NONE, C_REG, C_NONE, 16, 4, 0, 0},
 	{ASLLV, C_SCON, C_NONE, C_NONE, C_REG, C_NONE, 16, 4, 0, 0},
 
+	{ABSTRPICKW, C_SCON, C_REG, C_SCON, C_REG, C_NONE, 17, 4, 0, 0},
+	{ABSTRPICKW, C_SCON, C_REG, C_ZCON, C_REG, C_NONE, 17, 4, 0, 0},
+	{ABSTRPICKW, C_ZCON, C_REG, C_ZCON, C_REG, C_NONE, 17, 4, 0, 0},
+
 	{ASYSCALL, C_NONE, C_NONE, C_NONE, C_NONE, C_NONE, 5, 4, 0, 0},
 	{ASYSCALL, C_ANDCON, C_NONE, C_NONE, C_NONE, C_NONE, 5, 4, 0, 0},
 
@@ -1159,6 +1163,11 @@ func buildop(ctxt *obj.Link) {
 			opset(ASRLV, r0)
 			opset(AROTRV, r0)
 
+		case ABSTRPICKW:
+			opset(ABSTRPICKV, r0)
+			opset(ABSTRINSW, r0)
+			opset(ABSTRINSV, r0)
+
 		case ASUB:
 			opset(ASUBU, r0)
 			opset(ANOR, r0)
@@ -1265,6 +1274,14 @@ func OP_15I(op uint32, i uint32) uint32 {
 	return op | (i&0x7FFF)<<0
 }
 
+// i1 -> msb
+// r2 -> rj
+// i3 -> lsb
+// r4 -> rd
+func OP_IRIR(op uint32, i1 uint32, r2 uint32, i3 uint32, r4 uint32) uint32 {
+	return op | (i1 << 16) | (r2&0x1F)<<5 | (i3 << 10) | (r4&0x1F)<<0
+}
+
 // Encoding for the 'b' or 'bl' instruction.
 func OP_B_BL(op uint32, i uint32) uint32 {
 	return op | ((i & 0xFFFF) << 10) | ((i >> 16) & 0x3FF)
@@ -1478,6 +1495,26 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
 			o1 = OP_16IRR(c.opirr(p.As), uint32(v)&0x1f, uint32(r), uint32(p.To.Reg))
 		}
 
+	case 17: // bstrpickw $msbw, r1, $lsbw, r2
+		rd, rj := p.To.Reg, p.Reg
+		if rj == obj.REG_NONE {
+			rj = rd
+		}
+		msb, lsb := p.From.Offset, p.GetFrom3().Offset
+
+		// check the range of msb and lsb
+		var b uint32
+		if p.As == ABSTRPICKW || p.As == ABSTRINSW {
+			b = 32
+		} else {
+			b = 64
+		}
+		if lsb < 0 || uint32(lsb) >= b || msb < 0 || uint32(msb) >= b || uint32(lsb) > uint32(msb) {
+			c.ctxt.Diag("illegal bit number\n%v", p)
+		}
+
+		o1 = OP_IRIR(c.opirir(p.As), uint32(msb), uint32(rj), uint32(lsb), uint32(rd))
+
 	case 18: // jmp [r1],0(r2)
 		r := int(p.Reg)
 		if r == 0 {
@@ -2250,6 +2287,21 @@ func (c *ctxt0) opirr(a obj.As) uint32 {
 	return 0
 }
 
+func (c *ctxt0) opirir(a obj.As) uint32 {
+	switch a {
+	case ABSTRINSW:
+		return 0x3<<21 | 0x0<<15 // bstrins.w
+	case ABSTRINSV:
+		return 0x2 << 22 // bstrins.d
+	case ABSTRPICKW:
+		return 0x3<<21 | 0x1<<15 // bstrpick.w
+	case ABSTRPICKV:
+		return 0x3 << 22 // bstrpick.d
+	}
+
+	return 0
+}
+
 func (c *ctxt0) specailFpMovInst(a obj.As, fclass int, tclass int) uint32 {
 	switch a {
 	case AMOVV:
diff --git a/src/cmd/internal/obj/loong64/doc.go b/src/cmd/internal/obj/loong64/doc.go
index c46d31d2c2..6ec53e7a17 100644
--- a/src/cmd/internal/obj/loong64/doc.go
+++ b/src/cmd/internal/obj/loong64/doc.go
@@ -63,13 +63,19 @@ Examples:
 	OR	R5, R6        <=> or R6, R6, R5
 
 Special Cases.
-Argument order is the same as in the GNU Loong64 syntax: jump instructions,
+(1) Argument order is the same as in the GNU Loong64 syntax: jump instructions,
 
 Examples:
 
 	BEQ	R0, R4, lable1  <=>  beq R0, R4, lable1
 	JMP	lable1          <=>  b lable1
 
+(2) BSTRINSW, BSTRINSV, BSTRPICKW, BSTRPICKV $<msb>, <Rj>, $<lsb>, <Rd>
+
+Examples:
+
+	BSTRPICKW $15, R4, $6, R5  <=>  bstrpick.w r5, r4, 15, 6
+
 2. Expressions for special arguments.
 
 Memory references: a base register and an offset register is written as (Rbase)(Roff).