diff --git a/internal/opcodesxml/opcodesxml.go b/internal/opcodesxml/opcodesxml.go
index e2a4dd0..273b4e6 100644
--- a/internal/opcodesxml/opcodesxml.go
+++ b/internal/opcodesxml/opcodesxml.go
@@ -45,6 +45,7 @@ type Form struct {
 	Operands         []Operand         `xml:"Operand"`
 	ImplicitOperands []ImplicitOperand `xml:"ImplicitOperand"`
 	ISA              []ISA             `xml:"ISA"`
+	Encoding         Encoding          `xml:"Encoding"`
 }
 
 type Operand struct {
@@ -62,3 +63,45 @@ type ImplicitOperand struct {
 type ISA struct {
 	ID string `xml:"id,attr"`
 }
+
+type Encoding struct {
+	REX  *REX  `xml:"REX"`
+	VEX  *VEX  `xml:"VEX"`
+	EVEX *EVEX `xml:"EVEX"`
+}
+
+type REX struct {
+	Mandatory bool   `xml:"mandatory,attr"`
+	W         int    `xml:"W,attr"`
+	R         string `xml:"R,attr"`
+	X         string `xml:"X,attr"`
+	B         string `xml:"B,attr"`
+}
+
+type VEX struct {
+	Type string `xml:"type,attr"`
+	W    int    `xml:"W,attr"`
+	L    int    `xml:"L,attr"`
+	M5   string `xml:"m-mmmm,attr"`
+	PP   string `xml:"pp,attr"`
+	R    string `xml:"R,attr"`
+	X    string `xml:"X,attr"`
+	B    string `xml:"B,attr"`
+	V4   string `xml:"vvvv,attr"`
+}
+
+type EVEX struct {
+	M2      string `xml:"mm,attr"`
+	PP      string `xml:"pp,attr"`
+	W       int    `xml:"W,attr"`
+	LL      string `xml:"LL,attr"`
+	V4      string `xml:"vvvv,attr"`
+	V       string `xml:"V,attr"`
+	RR      string `xml:"RR,attr"`
+	B       string `xml:"B,attr"`
+	X       string `xml:"X,attr"`
+	Bsml    string `xml:"b,attr"`
+	A3      string `xml:"aaa,attr"`
+	Z       string `xml:"Z,attr"`
+	Disp8xN string `xml:"disp8xN,attr"`
+}
diff --git a/internal/opcodesxml/opcodesxml_test.go b/internal/opcodesxml/opcodesxml_test.go
index 24a16c0..f3f8822 100644
--- a/internal/opcodesxml/opcodesxml_test.go
+++ b/internal/opcodesxml/opcodesxml_test.go
@@ -1,14 +1,12 @@
 package opcodesxml
 
 import (
-	"fmt"
 	"testing"
 )
 
 func TestReadFile(t *testing.T) {
-	is, err := ReadFile("testdata/x86_64.xml")
+	_, err := ReadFile("testdata/x86_64.xml")
 	if err != nil {
 		t.Fatal(err)
 	}
-	fmt.Printf("%#v\n", is)
 }