feat(arch): add the amd64 fp16 packed conversion family

Assisted-by: GLM 5.3

arch/arm64_ext.go

@@ -444,6 +444,18 @@ const (
 	// half-width companion of the source, equal at 128 bits: VCVTNEPS2BF16
 	// Y6, Z5.  Operands: src, dest.
 	ExtFormAmdVec2Half
+	// ExtFormAmdVec2Wide is the two-vector form whose source is the half-width
+	// companion of the destination, equal at 128 bits: VCVTPH2DQ Z6, Y5, where
+	// L'L names the destination.  Operands: src, dest.
+	ExtFormAmdVec2Wide
+	// ExtFormAmdVec2Quarter is the two-vector form whose source is the
+	// quarter-width companion of the destination, the XMM class at every
+	// length: VCVTPH2QQ Z6, X5.  Operands: src, dest.
+	ExtFormAmdVec2Quarter
+	// ExtFormAmdVec2ToQuarter is the two-vector form whose destination is the
+	// quarter-width companion of the source, the XMM class at every length:
+	// VCVTQQ2PH X6, Z5.  Operands: src, dest.
+	ExtFormAmdVec2ToQuarter
 	// ExtFormAmdMask2 is the form with an opmask destination and two vector
 	// sources: VP2INTERSECTD K0, Z2, Z1.  Operands: src1, src2, dest.
 	ExtFormAmdMask2
@@ -668,7 +680,8 @@ func (f ExtForm) Arity() int {
 		return 2
 	case ExtFormAmdVec3, ExtFormAmdMask2, ExtFormAmdVecGprVec:
 		return 3
-	case ExtFormAmdVec2, ExtFormAmdVec2Half, ExtFormAmdGprVec, ExtFormAmdVecGpr:
+	case ExtFormAmdVec2, ExtFormAmdVec2Half, ExtFormAmdVec2Wide, ExtFormAmdVec2Quarter,
+		ExtFormAmdVec2ToQuarter, ExtFormAmdGprVec, ExtFormAmdVecGpr:
 		return 2
 	case ExtFormAmdVec3Imm, ExtFormAmdMask2Imm:
 		return 4
@@ -777,6 +790,12 @@ func (f ExtForm) String() string {
 		return "two vectors"
 	case ExtFormAmdVec2Half:
 		return "two vectors, half-width destination"
+	case ExtFormAmdVec2Wide:
+		return "two vectors, half-width source"
+	case ExtFormAmdVec2Quarter:
+		return "two vectors, quarter-width source"
+	case ExtFormAmdVec2ToQuarter:
+		return "two vectors, quarter-width destination"
 	case ExtFormAmdMask2:
 		return "two vectors into an opmask"
 	case ExtFormAmdVecGprVec:
@@ -1037,7 +1056,8 @@ func (in ExtInstr) Encode(ops []ExtOperand) ([]byte, error) {
 		return in.encodeSignedImmediate(ops)
 	case ExtFormAmdVec3, ExtFormAmdVec2, ExtFormAmdVec2Half, ExtFormAmdMask2,
 		ExtFormAmdVecGprVec, ExtFormAmdGprVec, ExtFormAmdVecGpr,
-		ExtFormAmdVec3Imm, ExtFormAmdMask2Imm, ExtFormAmdMemVec, ExtFormAmdVecMem:
+		ExtFormAmdVec3Imm, ExtFormAmdMask2Imm, ExtFormAmdMemVec, ExtFormAmdVecMem,
+		ExtFormAmdVec2Wide, ExtFormAmdVec2Quarter, ExtFormAmdVec2ToQuarter:
 		return in.encodeAmd64(ops)
 	case ExtFormPredicateLogical, ExtFormPredicateSelect:
 		return in.encodePredicateLogical(ops)