Merge branch 'vm' into dauTT/vm-DUP-NIP-OVER-PICK-opcode

pkg/vm/csharp-interop-test/push/pushbytes1.json

@@ -0,0 +1,81 @@
+{
+    "category": "Push",
+    "name": "PUSHBYTES1",
+    "tests":
+    [
+        {
+            "name": "Good definition",
+            "script": "0x0100",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Break",
+                        "invocationStack":
+                        [
+                            {
+                                "scriptHash": "0xFBC22D517F38E7612798ECE8E5957CF6C41D8CAF",
+                                "instructionPointer": 2,
+                                "nextInstruction": "RET",
+                                "evaluationStack":
+                                [
+                                    {
+                                        "type": "ByteArray",
+                                        "value": "0x00"
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Halt",
+                        "resultStack":
+                        [
+                            {
+                                "type": "ByteArray",
+                                "value": "0x00"
+                            }
+                        ]
+                    }
+                }
+            ]
+        },
+        {
+            "name": "Wrong definition (without enough length)",
+            "script": "0x01",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Fault",
+                        "invocationStack":
+                        [
+                            {
+                                "scriptHash": "0xC51B66BCED5E4491001BD702669770DCCF440982",
+                                "instructionPointer": 1,
+                                "nextInstruction": "RET"
+                            }
+                        ]
+                    }
+                }
+            ]
+        }
+    ]
+}

pkg/vm/csharp-interop-test/readme.md

@@ -0,0 +1,6 @@
+## Package VM Interop
+
+
+This package will use the tests in the neo-vm repo to test interopabilty
+
+

pkg/vm/csharp-interop-test/testStruct.go

@@ -0,0 +1,26 @@
+package csharpinterop
+
+// VMUnitTest is a struct for capturing the fields in the json files
+type VMUnitTest struct {
+	Category string `json:"category"`
+	Name     string `json:"name"`
+	Tests    []struct {
+		Name   string `json:"name"`
+		Script string `json:"script"`
+		Steps  []struct {
+			Actions []string `json:"actions"`
+			Result  struct {
+				State           string `json:"state"`
+				InvocationStack []struct {
+					ScriptHash         string `json:"scriptHash"`
+					InstructionPointer int    `json:"instructionPointer"`
+					NextInstruction    string `json:"nextInstruction"`
+					EvaluationStack    []struct {
+						Type  string `json:"type"`
+						Value string `json:"value"`
+					} `json:"evaluationStack"`
+				} `json:"invocationStack"`
+			} `json:"result"`
+		} `json:"steps"`
+	} `json:"tests"`
+}

pkg/vm/stack/Int.go

@@ -1,6 +1,9 @@
 package stack
 
-import "math/big"
+import (
+	"fmt"
+	"math/big"
+)
 
 // Int represents an integer on the stack
 type Int struct {
@@ -100,6 +103,18 @@ func (i *Int) Value() *big.Int {
 	return i.val
 }
 
+// Abs returns a stack integer whose underlying value is
+// the absolute value of the original stack integer.
+func (i *Int) Abs() (*Int, error) {
+	a := big.NewInt(0).Abs(i.Value())
+	b, err := NewInt(a)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
 // Lte returns a bool value from the comparison of two integers, a and b.
 // value is true if a <= b.
 // value is false if a > b.
@@ -114,18 +129,6 @@ func (i *Int) Gte(s *Int) bool {
 	return i.Value().Cmp(s.Value()) != -1
 }
 
-// Abs returns a stack integer whose underlying value is
-// the absolute value of the original stack integer.
-func (i *Int) Abs() (*Int, error) {
-	a := big.NewInt(0).Abs(i.Value())
-	b, err := NewInt(a)
-	if err != nil {
-		return nil, err
-	}
-
-	return b, nil
-}
-
 // Lt returns a bool value from the comparison of two integers, a and b.
 // value is true if a < b.
 // value is false if a >= b.
@@ -139,3 +142,64 @@ func (i *Int) Lt(s *Int) bool {
 func (i *Int) Gt(s *Int) bool {
 	return i.Value().Cmp(s.Value()) == 1
 }
+
+// Invert returns an Integer whose underlying value is the bitwise complement
+// of the original value.
+func (i *Int) Invert() (*Int, error) {
+	res := new(big.Int).Not(i.Value())
+	return NewInt(res)
+}
+
+// And returns an Integer whose underlying value is the result of the
+// application of the bitwise AND operator to the two original integers'
+// values.
+func (i *Int) And(s *Int) (*Int, error) {
+	res := new(big.Int).And(i.Value(), s.Value())
+	return NewInt(res)
+}
+
+// Or returns an Integer whose underlying value is the result of the
+// application of the bitwise OR operator to the two original integers'
+// values.
+func (i *Int) Or(s *Int) (*Int, error) {
+	res := new(big.Int).Or(i.Value(), s.Value())
+	return NewInt(res)
+}
+
+// Xor returns an Integer whose underlying value is the result of the
+// application of the bitwise XOR operator to the two original integers'
+// values.
+func (i *Int) Xor(s *Int) (*Int, error) {
+	res := new(big.Int).Xor(i.Value(), s.Value())
+	return NewInt(res)
+}
+
+// Hash overrides the default abstract hash method.
+func (i *Int) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", i, i.Value())
+	return KeyGenerator([]byte(data))
+}
+
+// Min returns the mininum between two integers.
+func Min(a *Int, b *Int) *Int {
+	if a.Lte(b) {
+		return a
+	}
+	return b
+}
+
+// Max returns the maximun between two integers.
+func Max(a *Int, b *Int) *Int {
+	if a.Gte(b) {
+		return a
+	}
+	return b
+}
+
+// Within returns a bool whose value is true
+// iff the value of the integer i is within the specified
+// range [a,b) (left-inclusive).
+func (i *Int) Within(a *Int, b *Int) bool {
+	// i >= a && i < b
+	return i.Gte(a) && i.Lt(b)
+}

pkg/vm/stack/array.go

@@ -1,5 +1,9 @@
 package stack
 
+import (
+	"fmt"
+)
+
 // Array represents an Array of stackItems on the stack
 type Array struct {
 	*abstractItem
@@ -11,3 +15,22 @@ type Array struct {
 func (a *Array) Array() (*Array, error) {
 	return a, nil
 }
+
+//Value returns the underlying Array's value
+func (a *Array) Value() []Item {
+	return a.val
+}
+
+// NewArray returns a new Array.
+func NewArray(val []Item) *Array {
+	return &Array{
+		&abstractItem{},
+		val,
+	}
+}
+
+// Hash overrides the default abstract hash method.
+func (a *Array) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", a, a.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/boolean.go

@@ -1,5 +1,9 @@
 package stack
 
+import (
+	"fmt"
+)
+
 // Boolean represents a boolean value on the stack
 type Boolean struct {
 	*abstractItem
@@ -44,3 +48,9 @@ func (b *Boolean) Or(a *Boolean) *Boolean {
 	c := b.Value() || a.Value()
 	return NewBoolean(c)
 }
+
+// Hash overrides the default abstract hash method.
+func (b *Boolean) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", b, b.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/bytearray.go

@@ -3,6 +3,7 @@ package stack
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"math/big"
 	"strconv"
 )
@@ -69,3 +70,14 @@ func reverse(b []byte) []byte {
 
 	return dest
 }
+
+//Value returns the underlying ByteArray's value.
+func (ba *ByteArray) Value() []byte {
+	return ba.val
+}
+
+// Hash overrides the default abstract hash method.
+func (ba *ByteArray) Hash() (string, error) {
+	data := fmt.Sprintf("%T %v", ba, ba.Value())
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/context.go

@@ -3,6 +3,7 @@ package stack
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 )
 
 // Context represent the current execution context of the VM.
@@ -120,6 +121,11 @@ func (c *Context) ReadUint16() uint16 {
 	return val
 }
 
+// ReadInt16 reads a int16 from the script
+func (c *Context) ReadInt16() int16 {
+	return int16(c.ReadUint16())
+}
+
 // ReadByte reads one byte from the script
 func (c *Context) ReadByte() (byte, error) {
 	byt, err := c.ReadBytes(1)
@@ -150,3 +156,19 @@ func (c *Context) readVarBytes() ([]byte, error) {
 	}
 	return c.ReadBytes(int(n))
 }
+
+// SetIP sets the instruction pointer ip to a given integer.
+// Returns an error if ip is less than -1 or greater than LenInstr.
+func (c *Context) SetIP(ip int) error {
+	if ok := ip < -1 || ip > c.LenInstr(); ok {
+		return errors.New("invalid instruction pointer")
+	}
+	c.ip = ip
+	return nil
+}
+
+// Hash overrides the default abstract hash method.
+func (c *Context) Hash() (string, error) {
+	data := c.String() + fmt.Sprintf(" %v-%v-%v-%v-%v", c.ip, c.prog, c.breakPoints, c.Estack, c.Astack)
+	return KeyGenerator([]byte(data))
+}

pkg/vm/stack/map.go

@@ -0,0 +1,166 @@
+package stack
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
+)
+
+// Map represents a map of key, value pair on the stack.
+// Both key and value are stack Items.
+type Map struct {
+	*abstractItem
+	val map[Item]Item
+}
+
+// NewMap returns a Map stack Item given
+// a map whose keys and values are stack Items.
+func NewMap(val map[Item]Item) (*Map, error) {
+	return &Map{
+		abstractItem: &abstractItem{},
+		val:          val,
+	}, nil
+}
+
+// Map will overwrite the default implementation
+// to allow go to cast this item as an Map.
+func (m *Map) Map() (*Map, error) {
+	return m, nil
+}
+
+// Boolean overrides the default Boolean method
+// to convert an Map into a Boolean StackItem
+func (m *Map) Boolean() (*Boolean, error) {
+	return NewBoolean(true), nil
+}
+
+// ContainsKey returns a boolean whose value is true
+// iff the underlying map value contains the Item i
+// as a key.
+func (m *Map) ContainsKey(key Item) (*Boolean, error) {
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return nil, err
+		} else if ok.Value() == true {
+			return ok, nil
+		}
+
+	}
+	return NewBoolean(false), nil
+}
+
+// Value returns the underlying map's value
+func (m *Map) Value() map[Item]Item {
+	return m.val
+}
+
+// Remove removes the Item i from the
+// underlying map's value.
+func (m *Map) Remove(key Item) error {
+	var d Item
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return err
+		} else if ok.Value() == true {
+			d = k
+		}
+
+	}
+	if d != nil {
+		delete(m.Value(), d)
+	}
+	return nil
+}
+
+// Add inserts a new key, value pair of Items into
+// the underlying map's value.
+func (m *Map) Add(key Item, value Item) error {
+	for k := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return err
+		} else if ok.Value() == true {
+			return errors.New("try to insert duplicate key! ")
+		}
+	}
+	m.Value()[key] = value
+	return nil
+}
+
+// ValueOfKey tries to get the value of the key Item
+// from the map's underlying value.
+func (m *Map) ValueOfKey(key Item) (Item, error) {
+	for k, v := range m.Value() {
+		if ok, err := CompareHash(k, key); err != nil {
+			return nil, err
+		} else if ok.Value() == true {
+			return v, nil
+		}
+
+	}
+	return nil, nil
+
+}
+
+// Clear empties the the underlying map's value.
+func (m *Map) Clear() {
+	m.val = map[Item]Item{}
+}
+
+// CompareHash compare the the Hashes of two items.
+// If they are equal it returns a true boolean. Otherwise
+// it returns  false boolean. Item whose hashes are equal are
+// to be considered equal.
+func CompareHash(i1 Item, i2 Item) (*Boolean, error) {
+	hash1, err := i1.Hash()
+	if err != nil {
+		return nil, err
+	}
+	hash2, err := i2.Hash()
+	if err != nil {
+		return nil, err
+	}
+	if hash1 == hash2 {
+		return NewBoolean(true), nil
+	}
+
+	return NewBoolean(false), nil
+}
+
+// Hash overrides the default abstract hash method.
+func (m *Map) Hash() (string, error) {
+	var hashSlice sort.StringSlice = []string{}
+	var data = fmt.Sprintf("%T ", m)
+
+	for k, v := range m.Value() {
+		hk, err := k.Hash()
+		if err != nil {
+			return "", err
+		}
+		hv, err := v.Hash()
+
+		if err != nil {
+			return "", err
+		}
+
+		hashSlice = append(hashSlice, hk)
+		hashSlice = append(hashSlice, hv)
+	}
+	hashSlice.Sort()
+
+	for _, h := range hashSlice {
+		data += h
+	}
+
+	return KeyGenerator([]byte(data))
+}
+
+// KeyGenerator hashes a byte slice to obtain a unique identifier.
+func KeyGenerator(data []byte) (string, error) {
+	h, err := hash.Sha256([]byte(data))
+	if err != nil {
+		return "", err
+	}
+	return h.String(), nil
+}

pkg/vm/stack/map_test.go

@@ -0,0 +1,141 @@
+package stack
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap(t *testing.T) {
+	// define Map m for testing
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var c Item = NewByteArray([]byte{1, 2, 34})
+	var d Item = testMakeStackMap(t, map[Item]Item{
+		a: c,
+		b: a,
+	})
+	var e = NewContext([]byte{1, 2, 3, 4})
+	var f = NewArray([]Item{a, b})
+
+	val := map[Item]Item{
+		a: c,
+		b: a,
+		c: b,
+		d: a,
+		e: d,
+		f: e,
+	}
+	m := testMakeStackMap(t, val)
+
+	// test ValueOfKey
+	valueA, _ := m.ValueOfKey(testMakeStackInt(t, 10))
+	assert.Equal(t, c, valueA)
+
+	valueB, _ := m.ValueOfKey(b)
+	assert.Equal(t, a, valueB)
+
+	valueC, _ := m.ValueOfKey(NewByteArray([]byte{1, 2, 34}))
+	assert.Equal(t, b, valueC)
+
+	valueD, _ := m.ValueOfKey(testMakeStackMap(t, map[Item]Item{
+		b: a,
+		a: c,
+	}))
+	assert.Equal(t, a, valueD)
+
+	valueE, _ := m.ValueOfKey(NewContext([]byte{1, 2, 3, 4}))
+	assert.Equal(t, d, valueE)
+
+	valueF, _ := m.ValueOfKey(NewArray([]Item{a, b}))
+	assert.Equal(t, e, valueF)
+
+	valueX, _ := m.ValueOfKey(NewByteArray([]byte{1, 2, 35}))
+	assert.NotEqual(t, b, valueX)
+
+	checkA, err := m.ContainsKey(a)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkA.Value())
+
+	//test ContainsKey
+	checkB, err := m.ContainsKey(b)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkB.Value())
+
+	checkC, err := m.ContainsKey(c)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkC.Value())
+
+	checkD, err := m.ContainsKey(d)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkD.Value())
+
+	checkE, err := m.ContainsKey(e)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkE.Value())
+
+	//test CompareHash
+	val2 := map[Item]Item{
+		f: e,
+		e: d,
+		d: a,
+		c: b,
+		b: a,
+		a: c,
+	}
+	m2 := testMakeStackMap(t, val2)
+	checkMap, err := CompareHash(m, m2)
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkMap.Value())
+
+	checkBoolean, err := CompareHash(b, NewBoolean(true))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkBoolean.Value())
+
+	checkByteArray, err := CompareHash(c, NewByteArray([]byte{1, 2, 34}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkByteArray.Value())
+
+	checkContext, err := CompareHash(e, NewContext([]byte{1, 2, 3, 4}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkContext.Value())
+
+	checkArray, err := CompareHash(f, NewArray([]Item{a, b}))
+	assert.Nil(t, err)
+	assert.Equal(t, true, checkArray.Value())
+}
+
+func TestMapAdd(t *testing.T) {
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var m = testMakeStackMap(t, map[Item]Item{})
+
+	err := m.Add(a, a)
+	assert.Nil(t, err)
+	err = m.Add(b, a)
+	assert.Nil(t, err)
+
+	assert.Equal(t, 2, len(m.Value()))
+
+	expected := testMakeStackMap(t, map[Item]Item{b: a, a: a})
+	check, err := CompareHash(m, expected)
+	assert.Nil(t, err)
+	assert.Equal(t, true, check.Value())
+
+}
+
+func TestMapRemove(t *testing.T) {
+	var a Item = testMakeStackInt(t, 10)
+	var b Item = NewBoolean(true)
+	var m = testMakeStackMap(t, map[Item]Item{b: a, a: a})
+
+	err := m.Remove(a)
+	assert.Nil(t, err)
+	assert.Equal(t, 1, len(m.Value()))
+
+	expected := testMakeStackMap(t, map[Item]Item{b: a})
+	check, err := CompareHash(m, expected)
+	assert.Nil(t, err)
+	assert.Equal(t, true, check.Value())
+
+}

pkg/vm/stack/stack.go

@@ -142,22 +142,6 @@ func (ras *RandomAccess) Set(index uint16, item Item) error {
 	return nil
 }
 
-// Remove removes the n-item from the stack
-// starting from the top of the stack. In other words
-// the n-item to remove is located at the index "len(stack)-n-1"
-func (ras *RandomAccess) Remove(n uint16) (Item, error) {
-	if int(n) >= len(ras.vals) {
-		return nil, errors.New("index out of range")
-	}
-
-	index := uint16(len(ras.vals)) - n - 1
-	item := ras.vals[index]
-
-	ras.vals = append(ras.vals[:index], ras.vals[index+1:]...)
-
-	return item, nil
-}
-
 // Convenience Functions
 
 // PopInt will remove the last stack item that was added
@@ -189,3 +173,19 @@ func (ras *RandomAccess) PopBoolean() (*Boolean, error) {
 	}
 	return item.Boolean()
 }
+
+// Remove removes the n-item from the stack
+// starting from the top of the stack. In other words
+// the n-item to remove is located at the index "len(stack)-n-1"
+func (ras *RandomAccess) Remove(n uint16) (Item, error) {
+	if int(n) >= len(ras.vals) {
+		return nil, errors.New("index out of range")
+	}
+
+	index := uint16(len(ras.vals)) - n - 1
+	item := ras.vals[index]
+
+	ras.vals = append(ras.vals[:index], ras.vals[index+1:]...)
+
+	return item, nil
+}

pkg/vm/stack/stackitem.go

@@ -11,6 +11,8 @@ type Item interface {
 	ByteArray() (*ByteArray, error)
 	Array() (*Array, error)
 	Context() (*Context, error)
+	Map() (*Map, error)
+	Hash() (string, error)
 }
 
 // Represents an `abstract` stack item
@@ -47,3 +49,13 @@ func (a *abstractItem) Array() (*Array, error) {
 func (a *abstractItem) Context() (*Context, error) {
 	return nil, errors.New("This stack item is not of type context")
 }
+
+// Context is the default implementation for a stackItem
+// Implements Item interface
+func (a *abstractItem) Map() (*Map, error) {
+	return nil, errors.New("This stack item is not a map")
+}
+
+func (a *abstractItem) Hash() (string, error) {
+	return "", errors.New("This stack item need to override the Hash Method")
+}

pkg/vm/stack/test_helper.go

@@ -42,3 +42,15 @@ func testReadInt64(data []byte) int64 {
 	binary.Read(buf, binary.LittleEndian, &ret)
 	return ret
 }
+
+func testMakeStackMap(t *testing.T, m map[Item]Item) *Map {
+	a, err := NewMap(m)
+	assert.Nil(t, err)
+	return a
+}
+
+func testArray(t *testing.T, m map[Item]Item) *Map {
+	a, err := NewMap(m)
+	assert.Nil(t, err)
+	return a
+}

pkg/vm/vm_ops.go

@@ -5,38 +5,61 @@ import "github.com/CityOfZion/neo-go/pkg/vm/stack"
 type stackInfo func(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error)
 
 var opFunc = map[stack.Instruction]stackInfo{
-	stack.PICK:        PICK,
-	stack.OVER:        OVER,
-	stack.NIP:         NIP,
-	stack.DUP:         DUP,
-	stack.NUMEQUAL:    NumEqual,
-	stack.NUMNOTEQUAL: NumNotEqual,
-	stack.BOOLAND:     BoolAnd,
-	stack.BOOLOR:      BoolOr,
-	stack.LT:          Lt,
-	stack.LTE:         Lte,
-	stack.GT:          Gt,
-	stack.GTE:         Gte,
-	stack.SHR:         Shr,
-	stack.SHL:         Shl,
-	stack.INC:         Inc,
-	stack.DEC:         Dec,
-	stack.DIV:         Div,
-	stack.MOD:         Mod,
-	stack.NZ:          Nz,
-	stack.MUL:         Mul,
-	stack.ABS:         Abs,
-	stack.NOT:         Not,
-	stack.SIGN:        Sign,
-	stack.NEGATE:      Negate,
-	stack.ADD:         Add,
-	stack.SUB:         Sub,
-	stack.PUSHBYTES1:  PushNBytes,
-	stack.PUSHBYTES75: PushNBytes,
-	stack.RET:         RET,
-	stack.EQUAL:       EQUAL,
-	stack.THROWIFNOT:  THROWIFNOT,
-	stack.THROW:       THROW,
+	stack.PICK:            PICK,
+	stack.OVER:            OVER,
+	stack.NIP:             NIP,
+	stack.DUP:             DUP,
+	stack.DROP:            DROP,
+	stack.DEPTH:           DEPTH,
+	stack.XTUCK:           XTUCK,
+	stack.XSWAP:           XSWAP,
+	stack.XDROP:           XDROP,
+	stack.FROMALTSTACK:    FROMALTSTACK,
+	stack.TOALTSTACK:      TOALTSTACK,
+	stack.DUPFROMALTSTACK: DUPFROMALTSTACK,
+	stack.JMPIFNOT:        JMPIFNOT,
+	stack.JMPIF:           JMPIF,
+	stack.JMP:             JMP,
+	stack.NOP:             NOP,
+	stack.HASH256:         HASH256,
+	stack.HASH160:         HASH160,
+	stack.SHA256:          SHA256,
+	stack.SHA1:            SHA1,
+	stack.XOR:             Xor,
+	stack.OR:              Or,
+	stack.AND:             And,
+	stack.INVERT:          Invert,
+	stack.MIN:             Min,
+	stack.MAX:             Max,
+	stack.WITHIN:          Within,
+  stack.NUMEQUAL:        NumEqual,
+	stack.NUMNOTEQUAL:     NumNotEqual,
+	stack.BOOLAND:         BoolAnd,
+	stack.BOOLOR:          BoolOr,
+	stack.LT:              Lt,
+	stack.LTE:             Lte,
+	stack.GT:              Gt,
+	stack.GTE:             Gte,
+	stack.SHR:             Shr,
+	stack.SHL:             Shl,
+	stack.INC:             Inc,
+	stack.DEC:             Dec,
+	stack.DIV:             Div,
+	stack.MOD:             Mod,
+	stack.NZ:              Nz,
+	stack.MUL:             Mul,
+	stack.ABS:             Abs,
+	stack.NOT:             Not,
+	stack.SIGN:            Sign,
+	stack.NEGATE:          Negate,
+	stack.ADD:             Add,
+	stack.SUB:             Sub,
+	stack.PUSHBYTES1:      PushNBytes,
+	stack.PUSHBYTES75:     PushNBytes,
+	stack.RET:             RET,
+	stack.EQUAL:           EQUAL,
+	stack.THROWIFNOT:      THROWIFNOT,
+	stack.THROW:           THROW,
 }
 
 func init() {

pkg/vm/vm_ops_bitwise.go

@@ -15,3 +15,88 @@ func EQUAL(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, r
 	ctx.Estack.Push(itemA.Equals(itemB))
 	return NONE, nil
 }
+
+// Invert pops an integer x off of the stack and
+// pushes an integer on the stack whose value
+// is the bitwise complement of the value of x.
+// Returns an error if the popped value is not an integer or
+// if the bitwise complement cannot be taken.
+func Invert(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	i, err := ctx.Estack.PopInt()
+	if err != nil {
+		return FAULT, err
+	}
+
+	inv, err := i.Invert()
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(inv)
+
+	return NONE, nil
+}
+
+// And pops two integer off of the stack and
+// pushes an integer onto the stack whose value
+// is the result of the application of the bitwise AND
+// operator to the two original integers' values.
+// Returns an error if either items cannot be casted to an integer.
+func And(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res, err := operandA.And(operandB)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Or pops two integer off of the stack and
+// pushes an integer onto the stack whose value
+// is the result of the application of the bitwise OR
+// operator to the two original integers' values.
+// Returns an error if either items cannot be casted to an integer.
+func Or(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res, err := operandA.Or(operandB)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Xor pops two integer off of the stack and
+// pushes an integer onto the stack whose value
+// is the result of the application of the bitwise XOR
+// operator to the two original integers' values.
+// Returns an error if either items cannot be casted to an integer.
+func Xor(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res, err := operandA.Xor(operandB)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}

pkg/vm/vm_ops_bitwise_test.go

@@ -0,0 +1,137 @@
+package vm
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/vm/stack"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestInvertOp(t *testing.T) {
+
+	v := VM{}
+
+	// 0000 00110 = 5
+	a, err := stack.NewInt(big.NewInt(5))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+
+	// 1111 11001 = -6 (two complement representation)
+	v.executeOp(stack.INVERT, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(-6), item.Value().Int64())
+}
+
+func TestAndOp(t *testing.T) {
+
+	v := VM{}
+
+	// 110001 = 49
+	a, err := stack.NewInt(big.NewInt(49))
+	assert.Nil(t, err)
+
+	// 100011 = 35
+	b, err := stack.NewInt(big.NewInt(35))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	// 100001 = 33
+	v.executeOp(stack.AND, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(33), item.Value().Int64())
+}
+
+func TestOrOp(t *testing.T) {
+
+	v := VM{}
+
+	// 110001 = 49
+	a, err := stack.NewInt(big.NewInt(49))
+	assert.Nil(t, err)
+
+	// 100011 = 35
+	b, err := stack.NewInt(big.NewInt(35))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	// 110011 = 51 (49 OR 35)
+	v.executeOp(stack.OR, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(51), item.Value().Int64())
+}
+
+func TestXorOp(t *testing.T) {
+
+	v := VM{}
+
+	// 110001 = 49
+	a, err := stack.NewInt(big.NewInt(49))
+	assert.Nil(t, err)
+
+	// 100011 = 35
+	b, err := stack.NewInt(big.NewInt(35))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	// 010010 = 18 (49 XOR 35)
+	v.executeOp(stack.XOR, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(18), item.Value().Int64())
+}
+
+func TestEqualOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.EQUAL, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopBoolean()
+	assert.Nil(t, err)
+
+	assert.Equal(t, true, item.Value())
+}

pkg/vm/vm_ops_flow.go

@@ -25,3 +25,71 @@ func RET(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rst
 
 	return NONE, nil
 }
+
+// NOP Returns NONE VMState.
+func NOP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+	return NONE, nil
+}
+
+// JMP moves the instruction pointer to an offset which is
+// calculated base on the instructionPointerOffset method.
+// Returns and error if the offset is out of range.
+func JMP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+	offset := instructionPointerOffset(ctx)
+	if err := ctx.SetIP(offset); err != nil {
+		return FAULT, err
+
+	}
+
+	return NONE, nil
+}
+
+// JMPIF pops a boolean off of the stack and,
+// if the the boolean's value is true, it
+// moves the instruction pointer to an offset which is
+// calculated base on the instructionPointerOffset method.
+// Returns and error if the offset is out of range or
+// the popped item is not a boolean.
+func JMPIF(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+	b, err := ctx.Estack.PopBoolean()
+	if err != nil {
+		return FAULT, err
+	}
+
+	if b.Value() {
+		offset := instructionPointerOffset(ctx)
+		if err := ctx.SetIP(offset); err != nil {
+			return FAULT, err
+		}
+
+	}
+
+	return NONE, nil
+}
+
+// JMPIFNOT pops a boolean off of the stack and,
+// if the the boolean's value is false, it
+// moves the instruction pointer to an offset which is
+// calculated base on the instructionPointerOffset method.
+// Returns and error if the offset is out of range or
+// the popped item is not a boolean.
+func JMPIFNOT(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+	b, err := ctx.Estack.PopBoolean()
+	if err != nil {
+		return FAULT, err
+	}
+
+	if !b.Value() {
+		offset := instructionPointerOffset(ctx)
+		if err := ctx.SetIP(offset); err != nil {
+			return FAULT, err
+		}
+
+	}
+
+	return NONE, nil
+}
+
+func instructionPointerOffset(ctx *stack.Context) int {
+	return ctx.IP() + int(ctx.ReadInt16()) - 3
+}

pkg/vm/vm_ops_flow_test.go

@@ -0,0 +1,168 @@
+package vm
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/vm/stack"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNopOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+
+	v.executeOp(stack.NOP, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(10), item.Value().Int64())
+}
+
+func TestJmpOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{5, 0, 2, 3, 4})
+	ctx.Estack.Push(a)
+
+	// ctx.ip = -1
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+
+	// ctx.ip will be set to offset.
+	// offset = ctx.IP() + int(ctx.ReadInt16()) - 3
+	//        = 0 + 5 -3 = 2
+	v.executeOp(stack.JMP, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 3, ctx.IP())
+}
+
+// test JMPIF instruction with true boolean
+// on top of the stack
+func TestJmpIfOp1(t *testing.T) {
+
+	v := VM{}
+
+	a := stack.NewBoolean(true)
+
+	ctx := stack.NewContext([]byte{5, 0, 2, 3, 4})
+	ctx.Estack.Push(a)
+
+	// ctx.ip = -1
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+
+	// ctx.ip will be set to offset
+	// because the there is a true boolean
+	// on top of the stack.
+	// offset = ctx.IP() + int(ctx.ReadInt16()) - 3
+	//        = 0 + 5 -3 = 2
+	v.executeOp(stack.JMPIF, ctx)
+
+	// Stack should have 0 item
+	assert.Equal(t, 0, ctx.Estack.Len())
+
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 3, ctx.IP())
+}
+
+// test JMPIF instruction with false boolean
+// on top of the stack
+func TestJmpIfOp2(t *testing.T) {
+
+	v := VM{}
+
+	a := stack.NewBoolean(false)
+
+	ctx := stack.NewContext([]byte{5, 0, 2, 3, 4})
+	ctx.Estack.Push(a)
+
+	// ctx.ip = -1
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+
+	// nothing will happen because
+	// the value of the boolean on top of the stack
+	// is false
+	v.executeOp(stack.JMPIF, ctx)
+
+	// Stack should have 0 item
+	assert.Equal(t, 0, ctx.Estack.Len())
+
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+}
+
+// test JMPIFNOT instruction with true boolean
+// on top of the stack
+func TestJmpIfNotOp1(t *testing.T) {
+
+	v := VM{}
+
+	a := stack.NewBoolean(true)
+
+	ctx := stack.NewContext([]byte{5, 0, 2, 3, 4})
+	ctx.Estack.Push(a)
+
+	// ctx.ip = -1
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+
+	// nothing will happen because
+	// the value of the boolean on top of the stack
+	// is true
+	v.executeOp(stack.JMPIFNOT, ctx)
+
+	// Stack should have 0 item
+	assert.Equal(t, 0, ctx.Estack.Len())
+
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+}
+
+// test JMPIFNOT instruction with false boolean
+// on top of the stack
+func TestJmpIfNotOp2(t *testing.T) {
+
+	v := VM{}
+
+	a := stack.NewBoolean(false)
+
+	ctx := stack.NewContext([]byte{5, 0, 2, 3, 4})
+	ctx.Estack.Push(a)
+
+	// ctx.ip = -1
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 0, ctx.IP())
+
+	// ctx.ip will be set to offset
+	// because the there is a false boolean
+	// on top of the stack.
+	// offset = ctx.IP() + int(ctx.ReadInt16()) - 3
+	//        = 0 + 5 -3 = 2
+	v.executeOp(stack.JMPIFNOT, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 0, ctx.Estack.Len())
+
+	// ctx.IP() = ctx.ip + 1
+	assert.Equal(t, 3, ctx.IP())
+}

pkg/vm/vm_ops_maths.go

@@ -205,6 +205,54 @@ func NumNotEqual(op stack.Instruction, ctx *stack.Context, istack *stack.Invocat
 	return NONE, nil
 }
 
+// Min pops two integers, a and b, off of the stack and pushes an integer to the stack
+// whose value is is the minum between a and b's value.
+// Returns an error if either items cannot be casted to an integer
+func Min(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.Min(operandA, operandB)
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Max pops two integers, a and b, off of the stack and pushes an integer to the stack
+// whose value is is the maximum between a and b's value.
+// Returns an error if either items cannot be casted to an integer
+func Max(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	operandA, operandB, err := popTwoIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.Max(operandA, operandB)
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Within pops three integers, a, b, and c off of the stack and pushes a boolean to the stack
+// whose value is true iff c's value is within b's value (include) and a's value.
+// Returns an error if at least one item cannot be casted to an boolean.
+func Within(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	a, b, c, err := popThreeIntegers(ctx)
+	if err != nil {
+		return FAULT, err
+	}
+	res := stack.NewBoolean(c.Within(b, a))
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
 // Abs pops an integer off of the stack and pushes its absolute value onto the stack.
 // Returns an error if the popped value is not an integer or if the absolute value cannot be taken
 func Abs(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
@@ -434,6 +482,23 @@ func popTwoIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, error) {
 	return operandA, operandB, nil
 }
 
+func popThreeIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, *stack.Int, error) {
+	operandA, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	operandB, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	operandC, err := ctx.Estack.PopInt()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	return operandA, operandB, operandC, nil
+}
+
 func popTwoByteArrays(ctx *stack.Context) (*stack.ByteArray, *stack.ByteArray, error) {
 	// Pop first stack item and cast as byte array
 	ba1, err := ctx.Estack.PopByteArray()

pkg/vm/vm_ops_maths_test.go

@@ -13,9 +13,7 @@ func TestIncOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -26,9 +24,7 @@ func TestIncOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(21), item.Value().Int64())
 }
@@ -38,9 +34,7 @@ func TestDecOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -51,9 +45,7 @@ func TestDecOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(19), item.Value().Int64())
 }
@@ -63,13 +55,10 @@ func TestAddOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(23))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -80,9 +69,7 @@ func TestAddOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(43), item.Value().Int64())
 
@@ -93,13 +80,10 @@ func TestSubOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(30))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(40))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -110,9 +94,7 @@ func TestSubOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(-10), item.Value().Int64())
 
@@ -123,13 +105,10 @@ func TestDivOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(4))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -140,9 +119,7 @@ func TestDivOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(2), item.Value().Int64())
 }
@@ -152,13 +129,10 @@ func TestModOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(15))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(4))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -169,9 +143,7 @@ func TestModOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(3), item.Value().Int64())
 }
@@ -181,9 +153,7 @@ func TestNzOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -194,9 +164,7 @@ func TestNzOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -206,13 +174,10 @@ func TestMulOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -223,9 +188,7 @@ func TestMulOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(400), item.Value().Int64())
 }
@@ -235,9 +198,7 @@ func TestAbsOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -248,9 +209,7 @@ func TestAbsOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(20), item.Value().Int64())
 }
@@ -270,9 +229,7 @@ func TestNotOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -282,13 +239,10 @@ func TestNumEqual(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -299,9 +253,7 @@ func TestNumEqual(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -311,13 +263,10 @@ func TestNumNotEqual(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(5))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(6))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -328,9 +277,7 @@ func TestNumNotEqual(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -340,9 +287,7 @@ func TestSignOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -353,9 +298,7 @@ func TestSignOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(-1), item.Value().Int64())
 }
@@ -365,9 +308,7 @@ func TestNegateOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(-20))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a)
@@ -378,9 +319,7 @@ func TestNegateOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(20), item.Value().Int64())
 }
@@ -448,13 +387,10 @@ func TestShlOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(2))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(3))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -470,9 +406,7 @@ func TestShlOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(16), item.Value().Int64())
 }
@@ -482,13 +416,10 @@ func TestShrOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
+
 	b, err := stack.NewInt(big.NewInt(2))
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -504,9 +435,7 @@ func TestShrOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopInt()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, int64(2), item.Value().Int64())
 }
@@ -527,9 +456,7 @@ func TestBoolAndOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -550,9 +477,7 @@ func TestBoolOrOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	if err != nil {
-		t.Fail()
-	}
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }
@@ -562,10 +487,10 @@ func TestLtOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	b, err := stack.NewInt(big.NewInt(2))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -581,7 +506,7 @@ func TestLtOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	assert.Equal(t, false, item.Value())
 }
@@ -591,10 +516,10 @@ func TestGtOp(t *testing.T) {
 	v := VM{}
 
 	a, err := stack.NewInt(big.NewInt(10))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	b, err := stack.NewInt(big.NewInt(2))
-	assert.NoError(t, err)
+	assert.Nil(t, err)
 
 	ctx := stack.NewContext([]byte{})
 	ctx.Estack.Push(a).Push(b)
@@ -610,7 +535,89 @@ func TestGtOp(t *testing.T) {
 	assert.Equal(t, 1, ctx.Estack.Len())
 
 	item, err := ctx.Estack.PopBoolean()
-	assert.NoError(t, err)
+	assert.Nil(t, err)
+
+	assert.Equal(t, true, item.Value())
+}
+
+func TestMinOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.MIN, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(2), item.Value().Int64())
+}
+
+func TestMaxOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.MAX, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(10), item.Value().Int64())
+}
+
+func TestWithinOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(5))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	c, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b).Push(c)
+
+	// c is the first item popped.
+	// b is the second item popped.
+	// a is the third item popped.
+	// if a is within [b, c) we place a boolean,
+	// whose value is true, on top of the evaluation
+	// stack. Otherwise we place a boolean with
+	// false value.
+	v.executeOp(stack.WITHIN, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopBoolean()
+	assert.Nil(t, err)
 
 	assert.Equal(t, true, item.Value())
 }

pkg/vm/vm_ops_stackmani.go

@@ -1,6 +1,8 @@
 package vm
 
 import (
+	"math/big"
+
 	"github.com/CityOfZion/neo-go/pkg/vm/stack"
 )
 
@@ -26,6 +28,49 @@ func DUP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rst
 	if err != nil {
 		return FAULT, err
 	}
+	ctx.Estack.Push(item)
+
+	return NONE, nil
+}
+
+// XSWAP pops an integer n off of the stack and
+// swaps the n-item from the stack starting from
+// the top of the stack with the top stack item.
+func XSWAP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	n, err := ctx.Estack.PopInt()
+	if err != nil {
+		return FAULT, err
+	}
+	nItem, err := ctx.Estack.Peek(uint16(n.Value().Int64()))
+	if err != nil {
+		return FAULT, err
+	}
+	item, err := ctx.Estack.Peek(0)
+	if err != nil {
+		return FAULT, err
+	}
+
+	if err := ctx.Estack.Set(uint16(n.Value().Int64()), item); err != nil {
+		return FAULT, err
+	}
+
+	if err := ctx.Estack.Set(0, nItem); err != nil {
+		return FAULT, err
+	}
+
+	return NONE, nil
+}
+
+// DUPFROMALTSTACK duplicates the item on top of alternative stack and
+// puts it on top of evaluation stack.
+// Returns an error if the alt stack is empty.
+func DUPFROMALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	item, err := ctx.Astack.Peek(0)
+	if err != nil {
+		return FAULT, err
+	}
 
 	ctx.Estack.Push(item)
 
@@ -60,6 +105,73 @@ func OVER(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rs
 	return NONE, nil
 }
 
+// XTUCK pops an integer n off of the stack and
+// inserts the top stack item to the position len(stack)-n in the evaluation stack.
+func XTUCK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	n, err := ctx.Estack.PopInt()
+	if err != nil || n.Value().Int64() < 0 {
+		return FAULT, err
+	}
+
+	item, err := ctx.Estack.Peek(0)
+	if err != nil {
+		return FAULT, err
+	}
+	ras, err := ctx.Estack.Insert(uint16(n.Value().Int64()), item)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack = *ras
+
+	return NONE, nil
+}
+
+// TOALTSTACK  pops an item off of the evaluation stack and
+// pushes it on top of the alternative stack.
+// Returns an error if the alternative stack is empty.
+func TOALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	item, err := ctx.Estack.Pop()
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Astack.Push(item)
+
+	return NONE, nil
+}
+
+// DEPTH puts the number of stack items onto the stack.
+func DEPTH(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	l := ctx.Estack.Len()
+	length, err := stack.NewInt(big.NewInt(int64(l)))
+	if err != nil {
+		return FAULT, err
+	}
+
+  ctx.Estack.Push(length)
+
+	return NONE, nil
+}
+
+// FROMALTSTACK pops an item off of the alternative stack and
+// pushes it on top of the evaluation stack.
+// Returns an error if the evaluation stack is empty.
+func FROMALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	item, err := ctx.Astack.Pop()
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(item)
+
+	return NONE, nil
+}
+
 // PICK pops an integer n off of the stack and
 // copies the n-item starting from
 // the top of the stack onto the top stack item.
@@ -81,3 +193,34 @@ func PICK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rs
 
 	return NONE, nil
 }
+
+// DROP removes the the top stack item.
+// Returns error if the operation Pop cannot
+// be performed.
+func DROP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	_, err := ctx.Estack.Pop()
+	if err != nil {
+		return FAULT, err
+	}
+
+	return NONE, nil
+}
+
+// XDROP pops an integer n off of the stack and
+// removes the n-item from the stack starting from
+// the top of the stack.
+func XDROP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	n, err := ctx.Estack.PopInt()
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Remove(uint16(n.Value().Uint64()))
+	if err != nil {
+		return FAULT, err
+	}
+
+	return NONE, nil
+}

pkg/vm/vm_ops_stackmani_test.go

@@ -140,7 +140,7 @@ func TestPickOp(t *testing.T) {
 	itemB, err := ctx.Estack.PopInt()
 	assert.Nil(t, err)
 
-	itemA2, err := ctx.Estack.PopInt()
+  itemA2, err := ctx.Estack.PopInt()
 	assert.Nil(t, err)
 
 	assert.Equal(t, int64(3), itemA.Value().Int64())
@@ -149,3 +149,251 @@ func TestPickOp(t *testing.T) {
 	assert.Equal(t, int64(3), itemA2.Value().Int64())
 
 }
+func TestXswapOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(3))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(6))
+	assert.Nil(t, err)
+
+	c, err := stack.NewInt(big.NewInt(9))
+	assert.Nil(t, err)
+
+	d, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b).Push(c).Push(d)
+
+	// pop n (= d = 2) from the stack.
+	// we will swap the n-item which
+	// is located in position len(stack)-n-1 (= 3-2-1= 0)
+	// with the top stack item.
+	// The final stack will be [c,b,a]
+	v.executeOp(stack.XSWAP, ctx)
+
+	// Stack should have three items
+	assert.Equal(t, 3, ctx.Estack.Len())
+
+	itemA, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	itemB, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	itemC, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(3), itemA.Value().Int64())
+	assert.Equal(t, int64(6), itemB.Value().Int64())
+	assert.Equal(t, int64(9), itemC.Value().Int64())
+
+}
+
+func TestXTuckOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(3))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(6))
+	assert.Nil(t, err)
+
+	c, err := stack.NewInt(big.NewInt(9))
+	assert.Nil(t, err)
+
+	d, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b).Push(c).Push(d)
+
+	// pop n (= d = 2) from the stack
+	// and insert the top stack item c
+	// to the position len(stack)-n (= 3-2 = 1)
+	// of the stack.The final stack will be [a,c,b,c]
+	v.executeOp(stack.XTUCK, ctx)
+
+	// Stack should have four items
+	assert.Equal(t, 4, ctx.Estack.Len())
+
+	// c
+	item0, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+	// b
+	item1, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+	// c
+	item2, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+	// a
+	item3, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(9), item0.Value().Int64())
+	assert.Equal(t, int64(6), item1.Value().Int64())
+	assert.Equal(t, int64(9), item2.Value().Int64())
+	assert.Equal(t, int64(3), item3.Value().Int64())
+
+}
+
+func TestXDepthOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(3))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(6))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	// push integer whose value is len(stack) (2)
+	// on top of the stack
+	v.executeOp(stack.DEPTH, ctx)
+
+	// Stack should have three items
+	assert.Equal(t, 3, ctx.Estack.Len())
+
+	// len(stack)
+	item0, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+	// b
+	item1, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+	// a
+	item2, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(2), item0.Value().Int64())
+	assert.Equal(t, int64(6), item1.Value().Int64())
+	assert.Equal(t, int64(3), item2.Value().Int64())
+}
+
+func TestDupFromAltStackOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+	ctx.Astack.Push(b)
+
+	v.executeOp(stack.DUPFROMALTSTACK, ctx)
+
+	assert.Equal(t, 1, ctx.Astack.Len())
+	assert.Equal(t, 2, ctx.Estack.Len())
+
+	itemE, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	itemA, err := ctx.Astack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(2), itemE.Value().Int64())
+	assert.Equal(t, int64(2), itemA.Value().Int64())
+}
+
+func TestToAltStackOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+	ctx.Astack.Push(b)
+
+	v.executeOp(stack.TOALTSTACK, ctx)
+
+	assert.Equal(t, 2, ctx.Astack.Len())
+	assert.Equal(t, 0, ctx.Estack.Len())
+
+	item, err := ctx.Astack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(10), item.Value().Int64())
+}
+
+func TestFromAltStackOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+	ctx.Astack.Push(b)
+
+	v.executeOp(stack.FROMALTSTACK, ctx)
+
+	assert.Equal(t, 0, ctx.Astack.Len())
+	assert.Equal(t, 2, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(2), item.Value().Int64())
+}
+
+func TestXDropOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(3))
+	assert.Nil(t, err)
+
+	b, err := stack.NewInt(big.NewInt(6))
+	assert.Nil(t, err)
+
+	c, err := stack.NewInt(big.NewInt(9))
+	assert.Nil(t, err)
+
+	d, err := stack.NewInt(big.NewInt(2))
+	assert.Nil(t, err)
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a)
+	ctx.Estack.Push(b)
+	ctx.Estack.Push(c)
+	ctx.Estack.Push(d)
+
+	// pop n (= d = 2) from the stack.
+	// we will remove the n-item which
+	// is located at position
+	// len(stack)-n-1 = 3-2-1 = 0.
+	// Therefore a is removed from the stack.
+	// Only b, c remain on the stack.
+	v.executeOp(stack.XDROP, ctx)
+
+	assert.Equal(t, 2, ctx.Estack.Len())
+
+	itemC, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	itemB, err := ctx.Estack.PopInt()
+	assert.Nil(t, err)
+
+	assert.Equal(t, int64(6), itemB.Value().Int64())
+	assert.Equal(t, int64(9), itemC.Value().Int64())
+
+}

pkg/vm/vmopscrypto.go

@@ -0,0 +1,106 @@
+package vm
+
+import (
+	"crypto/sha1"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
+	"github.com/CityOfZion/neo-go/pkg/vm/stack"
+)
+
+// SHA1 pops an item off of the stack and
+// pushes a bytearray onto the stack whose value
+// is obtained by applying the sha1 algorithm to
+// the corresponding bytearray representation of the item.
+// Returns an error if the Pop method cannot be execute or
+// the popped item does not have a concrete bytearray implementation.
+func SHA1(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	ba, err := ctx.Estack.PopByteArray()
+	if err != nil {
+		return FAULT, err
+	}
+
+	alg := sha1.New()
+	alg.Write(ba.Value())
+	hash := alg.Sum(nil)
+	res := stack.NewByteArray(hash)
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// SHA256 pops an item off of the stack and
+// pushes a bytearray onto the stack whose value
+// is obtained by applying the Sha256 algorithm to
+// the corresponding bytearray representation of the item.
+// Returns an error if the Pop method cannot be execute or
+// the popped item does not have a concrete bytearray implementation.
+func SHA256(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	ba, err := ctx.Estack.PopByteArray()
+	if err != nil {
+		return FAULT, err
+	}
+
+	hash, err := hash.Sha256(ba.Value())
+	if err != nil {
+		return FAULT, err
+	}
+
+	res := stack.NewByteArray(hash.Bytes())
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// HASH160 pops an item off of the stack and
+// pushes a bytearray onto the stack whose value
+// is obtained by applying the Hash160 algorithm to
+// the corresponding bytearray representation of the item.
+// Returns an error if the Pop method cannot be execute or
+// the popped item does not have a concrete bytearray implementation.
+func HASH160(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	ba, err := ctx.Estack.PopByteArray()
+	if err != nil {
+		return FAULT, err
+	}
+
+	hash, err := hash.Hash160(ba.Value())
+	if err != nil {
+		return FAULT, err
+	}
+
+	res := stack.NewByteArray(hash.Bytes())
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// HASH256 pops an item off of the stack and
+// pushes a bytearray onto the stack whose value
+// is obtained by applying the Hash256 algorithm to
+// the corresponding bytearray representation of the item.
+// Returns an error if the Pop method cannot be execute or
+// the popped item does not have a concrete bytearray implementation.
+func HASH256(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
+
+	ba, err := ctx.Estack.PopByteArray()
+	if err != nil {
+		return FAULT, err
+	}
+
+	hash, err := hash.DoubleSha256(ba.Value())
+	if err != nil {
+		return FAULT, err
+	}
+
+	res := stack.NewByteArray(hash.Bytes())
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}

pkg/vm/vmopscrypto_test.go

@@ -0,0 +1,101 @@
+package vm
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/vm/stack"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSha1Op(t *testing.T) {
+
+	v := VM{}
+
+	ba1 := stack.NewByteArray([]byte("this is test string"))
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(ba1)
+
+	v.executeOp(stack.SHA1, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.Pop()
+	assert.Nil(t, err)
+
+	ba2, err := item.ByteArray()
+	assert.Nil(t, err)
+
+	assert.Equal(t, "62d40fe74cf301cbfbe55c2679b96352449fb26d", hex.EncodeToString(ba2.Value()))
+}
+
+func TestSha256Op(t *testing.T) {
+
+	v := VM{}
+
+	ba1 := stack.NewByteArray([]byte("this is test string"))
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(ba1)
+
+	v.executeOp(stack.SHA256, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.Pop()
+	assert.Nil(t, err)
+
+	ba2, err := item.ByteArray()
+	assert.Nil(t, err)
+
+	assert.Equal(t, "8e76c5b9e6be2559bedccbd0ff104ebe02358ba463a44a68e96caf55f9400de5", hex.EncodeToString(ba2.Value()))
+}
+
+func TestHash160Op(t *testing.T) {
+
+	v := VM{}
+
+	ba1 := stack.NewByteArray([]byte("this is test string"))
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(ba1)
+
+	v.executeOp(stack.HASH160, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.Pop()
+	assert.Nil(t, err)
+
+	ba2, err := item.ByteArray()
+	assert.Nil(t, err)
+
+	assert.Equal(t, "e9c052b05a762ca9961a975db52e5417d99d958c", hex.EncodeToString(ba2.Value()))
+}
+
+func TestHash256Op(t *testing.T) {
+
+	v := VM{}
+
+	ba1 := stack.NewByteArray([]byte("this is test string"))
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(ba1)
+
+	v.executeOp(stack.HASH256, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.Pop()
+	assert.Nil(t, err)
+
+	ba2, err := item.ByteArray()
+	assert.Nil(t, err)
+
+	assert.Equal(t, "90ef790ee2557a3f9a1ba0e6910a9ff0ea75af3767ea7380760d729ac9927a60", hex.EncodeToString(ba2.Value()))
+}