diff --git a/pkg/compiler/binary_expr_test.go b/pkg/compiler/binary_expr_test.go
index d3f5c0ab9..bf3f94c62 100644
--- a/pkg/compiler/binary_expr_test.go
+++ b/pkg/compiler/binary_expr_test.go
@@ -26,7 +26,7 @@ var binaryExprTestCases = []testCase{
 			return x
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"simple div",
@@ -97,7 +97,7 @@ var binaryExprTestCases = []testCase{
 			return 0
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"compare equal strings with eql",
@@ -139,7 +139,7 @@ var binaryExprTestCases = []testCase{
 			return 0
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"compare equal ints with eql",
@@ -167,7 +167,7 @@ var binaryExprTestCases = []testCase{
 			return 0
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"compare not equal ints with eql",
@@ -181,7 +181,7 @@ var binaryExprTestCases = []testCase{
 			return 0
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"compare not equal ints with neq",
diff --git a/pkg/compiler/for_test.go b/pkg/compiler/for_test.go
index 71160a41f..f3ea262f3 100644
--- a/pkg/compiler/for_test.go
+++ b/pkg/compiler/for_test.go
@@ -276,7 +276,7 @@ func TestIfUnaryInvert(t *testing.T) {
 			return 0
 		}
 	`
-	eval(t, src, []byte{})
+	eval(t, src, big.NewInt(0))
 }
 
 func TestAppendByte(t *testing.T) {
diff --git a/pkg/compiler/function_call_test.go b/pkg/compiler/function_call_test.go
index 8851078f0..c9d9ca04c 100644
--- a/pkg/compiler/function_call_test.go
+++ b/pkg/compiler/function_call_test.go
@@ -39,7 +39,7 @@ func TestNotAssignedFunctionCall(t *testing.T) {
 	// disable stack checks because it is hard right now
 	// to distinguish between simple function call traversal
 	// and the same traversal inside an assignment.
-	evalWithoutStackChecks(t, src, []byte{})
+	evalWithoutStackChecks(t, src, big.NewInt(0))
 }
 
 func TestMultipleFunctionCalls(t *testing.T) {
diff --git a/pkg/compiler/if_test.go b/pkg/compiler/if_test.go
index 91731460d..23077ecf9 100644
--- a/pkg/compiler/if_test.go
+++ b/pkg/compiler/if_test.go
@@ -30,7 +30,7 @@ func TestGT(t *testing.T) {
 			return 0
 		}
 	`
-	eval(t, src, []byte{})
+	eval(t, src, big.NewInt(0))
 }
 
 func TestGTE(t *testing.T) {
@@ -44,7 +44,7 @@ func TestGTE(t *testing.T) {
 			return 0
 		}
 	`
-	eval(t, src, []byte{})
+	eval(t, src, big.NewInt(0))
 }
 
 func TestLAND(t *testing.T) {
@@ -89,5 +89,5 @@ func TestNestedIF(t *testing.T) {
 			return 0
 		}
 	`
-	eval(t, src, []byte{})
+	eval(t, src, big.NewInt(0))
 }
diff --git a/pkg/compiler/import_test.go b/pkg/compiler/import_test.go
index 7c635be3e..def752427 100644
--- a/pkg/compiler/import_test.go
+++ b/pkg/compiler/import_test.go
@@ -32,7 +32,7 @@ func TestImportStruct(t *testing.T) {
 			 return b.Y
 	 	}
 	 `
-	eval(t, src, []byte{})
+	eval(t, src, big.NewInt(0))
 }
 
 func TestMultipleDirFileImport(t *testing.T) {
diff --git a/pkg/compiler/struct_test.go b/pkg/compiler/struct_test.go
index 6646f877d..208f6a11b 100644
--- a/pkg/compiler/struct_test.go
+++ b/pkg/compiler/struct_test.go
@@ -255,7 +255,7 @@ var structTestCases = []testCase{
 			return t.y
 		}
 		`,
-		[]byte{},
+		big.NewInt(0),
 	},
 	{
 		"test return struct from func",
diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index 3a084d55a..b860cec42 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -518,17 +518,14 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
 	}
 
 	switch op {
-	case opcode.PUSHM1, opcode.PUSH1, opcode.PUSH2, opcode.PUSH3,
+	case opcode.PUSHM1, opcode.PUSH0, opcode.PUSH1, opcode.PUSH2, opcode.PUSH3,
 		opcode.PUSH4, opcode.PUSH5, opcode.PUSH6, opcode.PUSH7,
 		opcode.PUSH8, opcode.PUSH9, opcode.PUSH10, opcode.PUSH11,
 		opcode.PUSH12, opcode.PUSH13, opcode.PUSH14, opcode.PUSH15,
 		opcode.PUSH16:
-		val := int(op) - int(opcode.PUSH1) + 1
+		val := int(op) - int(opcode.PUSH0)
 		v.estack.PushVal(val)
 
-	case opcode.PUSH0:
-		v.estack.PushVal([]byte{})
-
 	case opcode.PUSHDATA1, opcode.PUSHDATA2, opcode.PUSHDATA4:
 		v.estack.PushVal(parameter)