feat(arch): add the imm8 scalar FP16 controls to the amd64 extension layer

Assisted-by: GLM 5.3 Flash

asm/extension_amd64_test.go

@@ -37,6 +37,10 @@ func TestAmd64ExtensionRegistry(t *testing.T) {
 		{"VSQRTPH", 1},
 		{"VSCALEFSH", 1},
 		{"VGETEXPSH", 1},
+		{"VCMPSH", 1},
+		{"VGETMANTSH", 1},
+		{"VREDUCESH", 1},
+		{"VRNDSCALESH", 1},
 	} {
 		cands, ok := LookupExtension(arch.AMD64, tt.mnem)
 		if !ok {
@@ -50,8 +54,8 @@ func TestAmd64ExtensionRegistry(t *testing.T) {
 			t.Errorf("the %s lookup is not case-insensitive", tt.mnem)
 		}
 	}
-	if got := arch.Extensions(arch.AMD64); len(got) != 48 {
-		t.Errorf("the amd64 layer registers %d instructions, want 48", len(got))
+	if got := arch.Extensions(arch.AMD64); len(got) != 52 {
+		t.Errorf("the amd64 layer registers %d instructions, want 52", len(got))
 	}
 	if _, ok := LookupExtension(arch.AMD64, "NOSUCHINSTR"); ok {
 		t.Error("a non-extended mnemonic resolved")
@@ -115,6 +119,12 @@ func TestEncodeExtensionAmd64(t *testing.T) {
 		{"word move into an xmm", "VMOVW",
 			[]arch.ExtOperand{arch.ExtGpr64(12), arch.ExtXmm(30)},
 			"62457d086ef4"},
+		{"scalar compare into a mask", "VCMPSH",
+			[]arch.ExtOperand{arch.ExtImmediate(0x7b), arch.ExtXmm(29), arch.ExtXmm(28), arch.ExtMask(5)},
+			"62931600c2ec7b"},
+		{"mantissa extract with a control byte", "VGETMANTSH",
+			[]arch.ExtOperand{arch.ExtImmediate(0x0b), arch.ExtXmm(29), arch.ExtXmm(28), arch.ExtXmm(30)},
+			"6203140027f40b"},
 	} {
 		got, err := EncodeExtension(arch.AMD64, tt.mnem, tt.ops...)
 		if err != nil {