diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index 286307ae9..a6c89d833 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -39,68 +39,68 @@ func (op OpCode) IsStaticJump() bool {
 
 // 0x0 range - arithmetic ops.
 const (
-	STOP OpCode = iota
-	ADD
-	MUL
-	SUB
-	DIV
-	SDIV
-	MOD
-	SMOD
-	ADDMOD
-	MULMOD
-	EXP
-	SIGNEXTEND
+	STOP       OpCode = 0x0
+	ADD        OpCode = 0x1
+	MUL        OpCode = 0x2
+	SUB        OpCode = 0x3
+	DIV        OpCode = 0x4
+	SDIV       OpCode = 0x5
+	MOD        OpCode = 0x6
+	SMOD       OpCode = 0x7
+	ADDMOD     OpCode = 0x8
+	MULMOD     OpCode = 0x9
+	EXP        OpCode = 0xa
+	SIGNEXTEND OpCode = 0xb
 )
 
 // 0x10 range - comparison ops.
 const (
-	LT OpCode = iota + 0x10
-	GT
-	SLT
-	SGT
-	EQ
-	ISZERO
-	AND
-	OR
-	XOR
-	NOT
-	BYTE
-	SHL
-	SHR
-	SAR
+	LT     OpCode = 0x10
+	GT     OpCode = 0x11
+	SLT    OpCode = 0x12
+	SGT    OpCode = 0x13
+	EQ     OpCode = 0x14
+	ISZERO OpCode = 0x15
+	AND    OpCode = 0x16
+	OR     OpCode = 0x17
+	XOR    OpCode = 0x18
+	NOT    OpCode = 0x19
+	BYTE   OpCode = 0x1a
+	SHL    OpCode = 0x1b
+	SHR    OpCode = 0x1c
+	SAR    OpCode = 0x1d
 
 	SHA3 OpCode = 0x20
 )
 
 // 0x30 range - closure state.
 const (
-	ADDRESS OpCode = 0x30 + iota
-	BALANCE
-	ORIGIN
-	CALLER
-	CALLVALUE
-	CALLDATALOAD
-	CALLDATASIZE
-	CALLDATACOPY
-	CODESIZE
-	CODECOPY
-	GASPRICE
-	EXTCODESIZE
-	EXTCODECOPY
-	RETURNDATASIZE
-	RETURNDATACOPY
-	EXTCODEHASH
+	ADDRESS        OpCode = 0x30
+	BALANCE        OpCode = 0x31
+	ORIGIN         OpCode = 0x32
+	CALLER         OpCode = 0x33
+	CALLVALUE      OpCode = 0x34
+	CALLDATALOAD   OpCode = 0x35
+	CALLDATASIZE   OpCode = 0x36
+	CALLDATACOPY   OpCode = 0x37
+	CODESIZE       OpCode = 0x38
+	CODECOPY       OpCode = 0x39
+	GASPRICE       OpCode = 0x3a
+	EXTCODESIZE    OpCode = 0x3b
+	EXTCODECOPY    OpCode = 0x3c
+	RETURNDATASIZE OpCode = 0x3d
+	RETURNDATACOPY OpCode = 0x3e
+	EXTCODEHASH    OpCode = 0x3f
 )
 
 // 0x40 range - block operations.
 const (
-	BLOCKHASH OpCode = 0x40 + iota
-	COINBASE
-	TIMESTAMP
-	NUMBER
-	DIFFICULTY
-	GASLIMIT
+	BLOCKHASH   OpCode = 0x40
+	COINBASE    OpCode = 0x41
+	TIMESTAMP   OpCode = 0x42
+	NUMBER      OpCode = 0x43
+	DIFFICULTY  OpCode = 0x44
+	GASLIMIT    OpCode = 0x45
 	CHAINID     OpCode = 0x46
 	SELFBALANCE OpCode = 0x47
 	BASEFEE     OpCode = 0x48
@@ -122,7 +122,7 @@ const (
 	JUMPDEST OpCode = 0x5b
 )
 
-// 0x60 range.
+// 0x60 range - pushes.
 const (
 	PUSH1 OpCode = 0x60 + iota
 	PUSH2
@@ -156,7 +156,11 @@ const (
 	PUSH30
 	PUSH31
 	PUSH32
-	DUP1
+)
+
+// 0x80 range - dups.
+const (
+	DUP1 = 0x80 + iota
 	DUP2
 	DUP3
 	DUP4
@@ -172,7 +176,11 @@ const (
 	DUP14
 	DUP15
 	DUP16
-	SWAP1
+)
+
+// 0x90 range - swaps.
+const (
+	SWAP1 = 0x90 + iota
 	SWAP2
 	SWAP3
 	SWAP4
@@ -208,12 +216,13 @@ const (
 
 // 0xf0 range - closures.
 const (
-	CREATE OpCode = 0xf0 + iota
-	CALL
-	CALLCODE
-	RETURN
-	DELEGATECALL
-	CREATE2
+	CREATE       OpCode = 0xf0
+	CALL         OpCode = 0xf1
+	CALLCODE     OpCode = 0xf2
+	RETURN       OpCode = 0xf3
+	DELEGATECALL OpCode = 0xf4
+	CREATE2      OpCode = 0xf5
+
 	STATICCALL   OpCode = 0xfa
 	REVERT       OpCode = 0xfd
 	SELFDESTRUCT OpCode = 0xff