feat(arch): add the AVX512-FP16 scalar family to the amd64 extension layer

Assisted-by: GLM 5.3 Flash

arch/arm64_ext.go

@@ -266,11 +266,11 @@ const (
 	// dest.
 	ExtFormAmdVecGprVec
 	// ExtFormAmdGprVec is the two-operand form with a general-register
-	// source and a vector destination: VMOVW X1, EAX and VCVTSH2SI EAX, X1.
-	// Operands: gpr, dest.
+	// source and a vector destination: VMOVW X1, EAX.  Operands: gpr, dest.
 	ExtFormAmdGprVec
 	// ExtFormAmdVecGpr is the two-operand form with a vector source and a
-	// general-register destination: VMOVW EAX, X1.  Operands: src, dest.
+	// general-register destination: VMOVW EAX, X1 and VCVTSH2SI EAX, X1.
+	// Operands: src, dest.
 	ExtFormAmdVecGpr
 )