Implemented more arm64 instructions

src/arm/Sub_test.go

@@ -25,3 +25,20 @@ func TestSubRegisterNumber(t *testing.T) {
 		assert.DeepEqual(t, code, pattern.Code)
 	}
 }
+
+func TestSubRegisterRegister(t *testing.T) {
+	usagePatterns := []struct {
+		Destination cpu.Register
+		Source      cpu.Register
+		Operand     cpu.Register
+		Code        uint32
+	}{
+		{arm.X0, arm.X1, arm.X2, 0xCB020020},
+	}
+
+	for _, pattern := range usagePatterns {
+		t.Logf("sub %s, %s, %s", pattern.Destination, pattern.Source, pattern.Operand)
+		code := arm.SubRegisterRegister(pattern.Destination, pattern.Source, pattern.Operand)
+		assert.DeepEqual(t, code, pattern.Code)
+	}
+}