feat(arch): add the amd64 memory-operand mechanism to the extension layer

Assisted-by: GLM 5.3 Flash

arch/arm64_ext.go

@@ -34,6 +34,7 @@ const (
 	ExtKReg // opmask register K0-K7
 	ExtR32  // 32-bit general register EAX-R15D
 	ExtR64  // 64-bit general register RAX-R15
+	ExtMem  // base-relative memory operand, 4660(R8) style
 )
 
 // String returns a short label for the kind.
@@ -57,6 +58,8 @@ func (k ExtOperandKind) String() string {
 		return "32-bit general register"
 	case ExtR64:
 		return "64-bit general register"
+	case ExtMem:
+		return "memory operand"
 	default:
 		return "operand"
 	}
@@ -153,10 +156,14 @@ func (q ExtQualifier) String() string {
 // from the parsed statement; Encode consumes them.
 type ExtOperand struct {
 	Kind ExtOperandKind
-	Reg  int            // register number (Z: 0..31, P: 0..15)
+	// Reg is the register number (Z: 0..31, P: 0..15); under ExtMem it is
+	// the base general register, 0..15.
+	Reg  int
 	Arr  ExtArrangement // element-size suffix; ExtArrNone when bare
 	Qual ExtQualifier   // predicate qualifier; ExtQualNone elsewhere
-	Imm  int64          // immediate value (ExtImm only)
+	// Imm is the immediate value under ExtImm; under ExtMem it is the
+	// signed displacement the base carries.
+	Imm int64
 	// Shift carries the LSL amount an immediate form shifts the constant by
 	// before use (0 or 8 in the SVE add/subtract immediate class).  HasShift
 	// separates a spelled shift (validated as written) from an unshifted
@@ -185,6 +192,14 @@ func ExtShiftedImmediate(v int64, shift int) ExtOperand {
 	return ExtOperand{Kind: ExtImm, Imm: v, Shift: shift, HasShift: true}
 }
 
+// ExtMemory builds a base-relative memory operand, 4660(R8) style: the base
+// is a 64-bit general register number, 0..15, and the displacement rides the
+// ModR/M disp8 or disp32 form the encoder picks.  No index register and no
+// scale: the base-plus-displacement shape alone.
+func ExtMemory(base int, disp int64) ExtOperand {
+	return ExtOperand{Kind: ExtMem, Reg: base, Imm: disp}
+}
+
 // ExtField is one named field of the 32-bit encoding word: a bit offset from
 // the least significant end and the field's width.
 type ExtField struct {
@@ -282,6 +297,13 @@ const (
 	// where dest is an opmask register and the immediate's layout is named
 	// by the entry's Imm8 kind.
 	ExtFormAmdMask2Imm
+	// ExtFormAmdMemVec is the memory-load form: VMOVSH X30, 4660(R8) shape,
+	// the manual's xmm1, m16 lines that stand beside the register form.
+	// Operands: mem, dest.
+	ExtFormAmdMemVec
+	// ExtFormAmdVecMem is the memory-store form: VMOVSH 4660(R9), X29
+	// shape, the manual's m16, xmm1 lines.  Operands: src, mem.
+	ExtFormAmdVecMem
 )
 
 // Arity returns the operand count the form takes.
@@ -297,6 +319,8 @@ func (f ExtForm) Arity() int {
 		return 2
 	case ExtFormAmdVec3Imm, ExtFormAmdMask2Imm:
 		return 4
+	case ExtFormAmdMemVec, ExtFormAmdVecMem:
+		return 2
 	default:
 		return 0
 	}
@@ -350,6 +374,10 @@ func (f ExtForm) String() string {
 		return "immediate, three vectors"
 	case ExtFormAmdMask2Imm:
 		return "immediate, two vectors into an opmask"
+	case ExtFormAmdMemVec:
+		return "memory into a vector"
+	case ExtFormAmdVecMem:
+		return "a vector into memory"
 	default:
 		return "unknown form"
 	}
@@ -431,6 +459,14 @@ type ExtInstr struct {
 	// operand carries, ExtImm8None when the form takes none.  The arm64
 	// entries all carry the zero value.
 	Imm8 ExtImm8Kind
+	// Mem names the 1-based operand position that may carry a memory
+	// operand beside the register the position normally takes: 2 on the
+	// arithmetic whose second source the manual spells xmm3/m16, 1 on the
+	// narrow BF16 convert whose source it spells m256/m512.  Zero means
+	// the form takes registers alone.  The load and store shapes are forms
+	// of their own, ExtFormAmdMemVec and ExtFormAmdVecMem, and need no
+	// flag.  The arm64 entries all carry the zero value.
+	Mem int
 }
 
 // Encode assembles the operands into the 4 little-endian bytes of the
@@ -453,7 +489,7 @@ func (in ExtInstr) Encode(ops []ExtOperand) ([]byte, error) {
 		return in.encodeSignedImmediate(ops)
 	case ExtFormAmdVec3, ExtFormAmdVec2, ExtFormAmdVec2Half, ExtFormAmdMask2,
 		ExtFormAmdVecGprVec, ExtFormAmdGprVec, ExtFormAmdVecGpr,
-		ExtFormAmdVec3Imm, ExtFormAmdMask2Imm:
+		ExtFormAmdVec3Imm, ExtFormAmdMask2Imm, ExtFormAmdMemVec, ExtFormAmdVecMem:
 		return in.encodeAmd64(ops)
 	default:
 		return nil, fmt.Errorf("%s: unknown form %d", in.Name, in.Form)