完善龙芯机器指令解码

internal/native/loong64/decode.go

@@ -1,6 +1,10 @@
 package loong64
 
-import "wa-lang.org/wa/internal/native/abi"
+import (
+	"fmt"
+
+	"wa-lang.org/wa/internal/native/abi"
+)
 
 // 解析机器码指令
 func Decode(x uint32) (as abi.As, arg *abi.AsArgument, err error) {
@@ -10,5 +14,156 @@ func Decode(x uint32) (as abi.As, arg *abi.AsArgument, err error) {
 
 // 解析机器码指令
 func DecodeEx(x uint32) (as abi.As, arg *abi.AsArgument, argRaw *abi.AsRawArgument, err error) {
+	return decodeInst(x)
+}
+
+func decodeInst(x uint32) (as abi.As, arg *abi.AsArgument, argRaw *abi.AsRawArgument, err error) {
+	for _, op := range _AOpContextTable {
+		if op.mask == 0 && op.value == 0 {
+			continue
+		}
+		if x&op.mask == op.value {
+			return op.decodeInst(x)
+		}
+	}
+	err = fmt.Errorf("loong64.decodeInst(%x): not found", x)
+	return
+}
+
+func (op _OpContextType) decodeInst(x uint32) (as abi.As, arg *abi.AsArgument, argRaw *abi.AsRawArgument, err error) {
+	as = op.op
+	arg = new(abi.AsArgument)
+	argRaw = new(abi.AsRawArgument)
+
+	rd := (x >> (5 * 0)) & 0b11111
+	rj := (x >> (5 * 1)) & 0b11111
+	rk := (x >> (5 * 2)) & 0b11111
+	ra := (x >> (5 * 3)) & 0b11111
+
+	_, _, _, _ = rd, rj, rk, ra
+
+	for _, argTyp := range op.args {
+		switch argTyp {
+		case 0: // 空参数
+			return
+
+		// 1-5 bit
+		case arg_fd:
+			argRaw.Rd = rd
+			arg.Rd, _ = op.decodeRegF(rd)
+		case arg_fj:
+			argRaw.Rs1 = rj
+			arg.Rs1, _ = op.decodeRegF(rd)
+		case arg_fk:
+			argRaw.Rs2 = rk
+			arg.Rs2, _ = op.decodeRegF(rd)
+		case arg_fa:
+			argRaw.Rs3 = ra
+			arg.Rs3, _ = op.decodeRegF(rd)
+		case arg_rd:
+			argRaw.Rd = rd
+			arg.Rd, _ = op.decodeRegI(rd)
+
+		// 6-10 bit
+		case arg_rj:
+			argRaw.Rs1 = rj
+			arg.Rs1, _ = op.decodeRegI(rd)
+		case arg_rk:
+			argRaw.Rs2 = rk
+			arg.Rs2, _ = op.decodeRegI(rd)
+		case arg_op_4_0:
+			panic("TODO")
+		case arg_fcsr_4_0:
+			panic("TODO")
+		case arg_fcsr_9_5:
+			panic("TODO")
+
+		// 11-15 bit
+		case arg_csr_23_10:
+			panic("TODO")
+		case arg_cd:
+			panic("TODO")
+		case arg_cj:
+			panic("TODO")
+		case arg_ca:
+			panic("TODO")
+		case arg_sa2_16_15:
+			panic("TODO")
+
+		// 16-20 bit
+		case arg_sa3_17_15:
+			panic("TODO")
+		case arg_code_4_0:
+			panic("TODO")
+		case arg_code_14_0:
+			panic("TODO")
+		case arg_ui5_14_10:
+			panic("TODO")
+		case arg_ui6_15_10:
+			panic("TODO")
+
+		// 21-25 bit
+		case arg_ui12_21_10:
+			panic("TODO")
+		case arg_lsbw:
+			panic("TODO") // 需要2个立即数
+		case arg_msbw:
+			panic("TODO") // 需要2个立即数
+		case arg_lsbd:
+			panic("TODO") // 需要2个立即数
+		case arg_msbd:
+			panic("TODO") // 需要2个立即数
+
+		// 26-30 bit
+		case arg_hint_4_0:
+			panic("TODO")
+		case arg_hint_14_0:
+			panic("TODO")
+		case arg_level_14_0:
+			panic("TODO")
+		case arg_level_17_10:
+			panic("TODO")
+
+		case arg_seq_17_10:
+			panic("TODO")
+
+		// 31-35 bit
+		case arg_si12_21_10:
+			panic("TODO")
+		case arg_si14_23_10:
+			panic("TODO")
+		case arg_si16_25_10:
+			panic("TODO")
+		case arg_si20_24_5:
+			panic("TODO")
+		case arg_offset_20_0:
+			panic("TODO")
+
+		// 36~
+		case arg_offset_25_0:
+			panic("TODO")
+		case arg_offset_15_0:
+			panic("TODO")
+		}
+
+		panic("unreachable")
+	}
+
 	panic("TODO")
 }
+
+// 解码寄存器
+func (op _OpContextType) decodeRegI(r uint32) (reg abi.RegType, err error) {
+	if r <= 31 {
+		return abi.RegType(r) + REG_R0, nil
+	}
+	return 0, fmt.Errorf("badreg(%d)", r)
+}
+
+// 解码寄存器(浮点数)
+func (op _OpContextType) decodeRegF(r uint32) (reg abi.RegType, err error) {
+	if r <= 31 {
+		return abi.RegType(r) + REG_F0, nil
+	}
+	return 0, fmt.Errorf("badreg(%d)", r)
+}

internal/native/loong64/readme.md

@@ -1,5 +0,0 @@
-# 读取龙芯指令规范
-
-1. 下载英文版到当前目录 https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.pdf
-2. 执行 `go run spec.go`, 生成 `tables.go` 表格
-