Implemented DIV, MOD opcode (#237)

pkg/vm/stack/Int.go

@@ -46,6 +46,13 @@ func (i *Int) Mul(s *Int) (*Int, error) {
 	}, nil
 }
 
+// Div will divide one stackInteger by an other.
+func (i *Int) Div(s *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Div(i.val, s.val),
+	}, nil
+}
+
 // Mod will take the mod of two stackIntegers together
 func (i *Int) Mod(s *Int) (*Int, error) {
 	return &Int{

pkg/vm/vm_ops.go

@@ -7,6 +7,8 @@ type stackInfo func(op stack.Instruction, ctx *stack.Context, istack *stack.Invo
 var opFunc = map[stack.Instruction]stackInfo{
 	stack.INC:         Inc,
 	stack.DEC:         Dec,
+	stack.DIV:         Div,
+	stack.MOD:         Mod,
 	stack.NZ:          Nz,
 	stack.MUL:         Mul,
 	stack.ABS:         Abs,

pkg/vm/vm_ops_maths.go

@@ -94,6 +94,44 @@ func Dec(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rst
 	return NONE, nil
 }
 
+// Div divides one stack Item by an other.
+// Returns an error if either items cannot be casted to an integer
+// or if the division of the integers cannot be performed.
+func Div(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 := operandB.Div(operandA)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
+// Mod returns the mod of two stack Items.
+// Returns an error if either items cannot be casted to an integer
+// or if the mode of the integers cannot be performed.
+func Mod(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 := operandB.Mod(operandA)
+	if err != nil {
+		return FAULT, err
+	}
+
+	ctx.Estack.Push(res)
+
+	return NONE, nil
+}
+
 // Nz pops an integer from the stack.
 // Then pushes a boolean to the stack which evaluates to true
 // iff the integer was not zero.

pkg/vm/vm_ops_maths_test.go

@@ -118,6 +118,64 @@ func TestSubOp(t *testing.T) {
 
 }
 
+func TestDivOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(10))
+	if err != nil {
+		t.Fail()
+	}
+	b, err := stack.NewInt(big.NewInt(4))
+	if err != nil {
+		t.Fail()
+	}
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.DIV, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	if err != nil {
+		t.Fail()
+	}
+  
+	assert.Equal(t, int64(2), item.Value().Int64())
+}
+
+func TestModOp(t *testing.T) {
+
+	v := VM{}
+
+	a, err := stack.NewInt(big.NewInt(15))
+	if err != nil {
+		t.Fail()
+	}
+	b, err := stack.NewInt(big.NewInt(4))
+	if err != nil {
+		t.Fail()
+	}
+
+	ctx := stack.NewContext([]byte{})
+	ctx.Estack.Push(a).Push(b)
+
+	v.executeOp(stack.MOD, ctx)
+
+	// Stack should have one item
+	assert.Equal(t, 1, ctx.Estack.Len())
+
+	item, err := ctx.Estack.PopInt()
+	if err != nil {
+		t.Fail()
+	}
+
+	assert.Equal(t, int64(3), item.Value().Int64())
+}
+
 func TestNzOp(t *testing.T) {
 
 	v := VM{}
@@ -141,7 +199,6 @@ func TestNzOp(t *testing.T) {
 	}
 
 	assert.Equal(t, true, item.Value())
-
 }
 
 func TestMulOp(t *testing.T) {
@@ -171,7 +228,6 @@ func TestMulOp(t *testing.T) {
 	}
 
 	assert.Equal(t, int64(400), item.Value().Int64())
-
 }
 
 func TestAbsOp(t *testing.T) {