feat(arch): encode the amd64 embedded rounding and SAE decorations

Assisted-by: GLM 5.3

asm/extension_amd64_test.go

@@ -125,6 +125,12 @@ func TestEncodeExtensionAmd64(t *testing.T) {
 		{"mantissa extract with a control byte", "VGETMANTSH",
 			[]arch.ExtOperand{arch.ExtImmediate(0x0b), arch.ExtXmm(29), arch.ExtXmm(28), arch.ExtXmm(30)},
 			"6203140027f40b"},
+		{"packed fp16 add under embedded rounding", "VADDPH",
+			[]arch.ExtOperand{arch.ExtZmm(5), arch.ExtZmm(4), arch.ExtRounded(arch.ExtZmm(6), arch.ExtRoundTruncate)},
+			"62f5547858f4"},
+		{"scalar fp16 minimum with exceptions suppressed", "VMINSH",
+			[]arch.ExtOperand{arch.ExtXmm(5), arch.ExtXmm(4), arch.ExtRounded(arch.ExtXmm(6), arch.ExtRoundSAE)},
+			"62f556185df4"},
 	} {
 		got, err := EncodeExtension(arch.AMD64, tt.mnem, tt.ops...)
 		if err != nil {