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NeoVM Instructions

Built-in data types

NeoVM has following built-in data types:

Type Description
Array Implemented as a List<StackItem>, the StackItem is an abstract class, and all the built-in data types are inherited from it.
Boolean Implemented as two byte arrays, TRUE and FALSE.
Buffer Readonly byte array, implemented as a buffer array byte[]
ByteString Readonly byte array, implemented as a ReadOnlyMemory<byte>
Integer Implemented as a BigInteger value.
InteropInterface Interoperable interface
Map Implemented as a key-value pair Dictionary<StackItem, StackItem>.
Null Null type
Pointer Implemented as a context Script and an instruction Position
Struct Inherited from Array, a Clone method is added and Equals method is overridden.
  • CompoundType : Compound type, which includes Array, Map and Struct。
  • PrimitiveType: Basic type which includes Boolean, ByteString and Integer。
// boolean type
private static readonly byte[] TRUE = { 1 };
private static readonly byte[] FALSE = { 0 };

private bool value;

Instructions

NeoVM has implemented 189 instructions. The categories are as follows:

Constant Flow Control Stack Operation Slot Operation String Operation Logical Operation Arithmetic Operation Advanced Data Structure Type Operation
29 32 15 50 6 6 25 18 3

Details of each instruction in each category are introduced as follows.

Constants

The constant instructions mainly complete the function of pushing constants or arrays into the EvaluationStack.

PUSHINT

Instruction PUSHINT8, PUSHINT16, PUSHINT32, PUSHINT64, PUSHINT128, PUSHINT256
Bytecode 0x00, 0x01, 0x02, 0x03, 0x04, 0x05
Fee 0.00000001 GAS, 0.00000001 GAS, 0.00000001 GAS, 0.00000001 GAS, 0.00000004 GAS, 0.00000004 GAS
Function Push an integer onto the stack, the bit length of which is specified with the number 8\16\32\64\128\256.

PUSHA

Instruction PUSHA
Bytecode 0x0A
Fee 0.00000004 GAS
Function Convert the next four bytes to an address, and push the address onto the stack.

PUSHNULL

Instruction PUSHNULL
Bytecode 0x0B
Fee 0.00000001 GAS
Function The item null is pushed onto the stack.

PUSHDATA

Instruction PUSHDATA1, PUSHDATA2, PUSHDATA4
Bytecode 0x0C, 0x0D, 0x0E
Fee 0.00000008 GAS, 0.00000512 GAS, 0.00004096 GAS
Function The next n bytes contain the number of bytes to be pushed onto the stack, where n is specified by 1|2|4.

PUSHM1

Instruction PUSHM1
Bytecode 0x0F
Fee 0.00000001 GAS
Function The number -1 is pushed onto the stack.

PUSHN

Instruction PUSH0~PUSH16
Bytecode 0x10~0x20
Fee 0.00000001 GAS
Function The number n is pushed onto the stack，where n is specified by 0~16.

Flow Control

It's used to control the running process of NeoVM, including jump, call and other instructions.

NOP

Instruction NOP
Bytecode 0x21
Fee 0.00000001 GAS
Function The NOP operation does nothing. It is intended to fill in space if opcodes are patched.

JMP

Instruction JMP
Bytecode 0x22
Fee 0.00000002 GAS
Function Unconditionally transfers control to a target instruction. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMP_L

Instruction JMP_L
Bytecode 0x23
Fee 0.00000002 GAS
Function Unconditionally transfers control to a target instruction. The target instruction is represented as a 4-bytes signed offset from the beginning of the current instruction.

JMPIF

Instruction JMPIF
Bytecode 0x24
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the value is true, not null, or non-zero. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPIF_L

Instruction JMPIF
Bytecode 0x25
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the value is true, not null, or non-zero. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPIFNOT

Instruction JMPIFNOT
Bytecode 0x26
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the value is false, a null reference, or zero. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPIFNOT_L

Instruction JMPIFNOT_L
Bytecode 0x27
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the value is false, a null reference, or zero. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPEQ

Instruction JMPEQ
Bytecode 0x28
Fee 0.00000002 GAS
Function Transfers control to a target instruction if two values are equal. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPEQ_L

Instruction JMPEQ_L
Bytecode 0x29
Fee 0.00000002 GAS
Function Transfers control to a target instruction if two values are equal. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPNE

Instruction JMPNE
Bytecode 0x2A
Fee 0.00000002 GAS
Function Transfers control to a target instruction when two values are not equal. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPNE_L

Instruction JMPNE_L
Bytecode 0x2B
Fee 0.00000002 GAS
Function Transfers control to a target instruction when two values are not equal. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPGT

Instruction JMPGT
Bytecode 0x2C
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is greater than the second value. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPGT_L

Instruction JMPGT_L
Bytecode 0x2D
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is greater than the second value. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPGE

Instruction JMPGE
Bytecode 0x2E
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is greater than or equal to the second value. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPGE_L

Instruction JMPGE_L
Bytecode 0x2F
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is greater than or equal to the second value. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPLT

Instruction JMPLT
Bytecode 0x30
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is less than the second value. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPLT_L

Instruction JMPLT_L
Bytecode 0x31
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is less than the second value. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

JMPLE

Instruction JMPLE
Bytecode 0x32
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is less than or equal to the second value. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

JMPLE_L

Instruction JMPLE_L
Bytecode 0x33
Fee 0.00000002 GAS
Function Transfers control to a target instruction if the first value is less than or equal to the second value. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

CALL

Instruction CALL
Bytecode 0x34
Fee 0.00000512 GAS
Function Calls the function at the target address which is represented as a 1-byte signed offset from the beginning of the current instruction.

CALL_L

Instruction CALL_L
Bytecode 0x35
Fee 0.00000512 GAS
Function Calls the function at the target address which is represented as a 4-bytes signed offset from the beginning of the current instruction.

CALLA

Instruction CALLA
Bytecode 0x36
Fee 0.00000512 GAS
Function Pops the address of a function from the stack, and call the function.

CALLT

Instruction CALLT
Bytecode 0x37
Fee 0.00032768 GAS
Function Pops the function Token from the stack, and call the function.

ABORT

Instruction ABORT
Bytecode 0x38
Fee 0 GAS
Function It turns the vm state to FAULT immediately, and the exception cannot be caught.

ASSERT

Instruction ASSERT
Bytecode 0x39
Fee 0.00000001 GAS
Function Pop the top value of the stack, if it is false, then exit vm execution and set vm state to FAULT.

THROW

Instruction THROW
Bytecode 0x3A
Fee 0.00000512 GAS
Function Throws the exception of stack top

TRY

Instruction TRY
Bytecode 0x3B
Fee 0.00000004 GAS
Function Enters the block of Try statement. The Catch and Finally address offset are represented as a 1-byte signed offset from the beginning of the current instruction.

TRY_L

Instruction TRY_L
Bytecode 0x3C
Fee 0.00000004 GAS
Function Enters the block of Try statement. The Catch and Finally address offset are represented as a 4-byte signed offset from the beginning of the current instruction.

ENDTRY

Instruction ENDTRY
Bytecode 0x3D
Fee 0.00000004 GAS
Function Terminates the block Try and unconditionally transfers control to a target instruction. The target instruction is represented as a 1-byte signed offset from the beginning of the current instruction.

ENDTRY_L

Instruction ENDTRY_L
Bytecode 0x3E
Fee 0.00000004 GAS
Function Terminates the block Try and unconditionally transfers control to a target instruction. The target instruction is represented as a 4-byte signed offset from the beginning of the current instruction.

ENDFINALLY

Instruction ENDFINALLY
Bytecode 0x3F
Fee 0.00000004 GAS
Function Terminates the block Finally and goes to the target instruction ENDTRY/ENDTRY_L if there is no exception, or throw the exception to the upper level again.

RET

Instruction RET
Bytecode 0x40
Fee 0 GAS
Function Returns from the current method.

SYSCALL

Instruction SYSCALL
Bytecode 0x41
Fee 0 GAS
Function Calls to an interop service.

Stack Operation

Copy, remove and swap the elements of the stack.

DEPTH

Instruction DEPTH
Bytecode 0x43
Fee 0.00000002 GAS
Function Puts the number of stack items onto the stack.

DROP

Instruction DROP
Bytecode 0x45
Fee 0.00000002 GAS
Function Removes the top stack item.

NIP

Instruction NIP
Bytecode 0x46
Fee 0.00000002 GAS
Function Removes the second-to-top stack item.

XDROP

Instruction XDROP
Bytecode 0x48
Fee 0.00000016 GAS
Function The item n back in the main stack is removed.
Function Gets the integer N from the top stack and removes elements indexed to N from the remaining elements of the stack.

CLEAR

Instruction CLEAR
Bytecode 0x49
Fee 0.00000016 GAS
Function Clear the stack

DUP

Instruction DUP
Bytecode 0x4A
Fee 0.00000002 GAS
Function Copies the top stack item to the top.

OVER

Instruction OVER
Bytecode 0x4B
Fee 0.00000002 GAS
Function Copies the second-to-top stack item to the top.

PICK

Instruction PICK
Bytecode 0x4D
Fee 0.00000002 GAS
Function Gets the integer N from the top stack and copies elements indexed to N from the remaining elements of the stack to the top.

TUCK

Instruction TUCK
Bytecode 0x4E
Fee 0.00000002 GAS
Function The item at the top of the stack is copied and inserted before the second-to-top item.

SWAP

Instruction SWAP
Bytecode 0x50
Fee 0.00000002 GAS
Function The top two items on the stack are swapped.

ROT

Instruction ROT
Bytecode 0x51
Fee 0.00000002 GAS
Function Moves the elements indexed to 2 to the top

ROLL

Instruction ROLL
Bytecode 0x52
Fee 0.00000016 GAS
Function Gets the integer N from the top stack and moves elements indexed to N from the remaining elements of the stack to the top.

REVERSE3

Instruction REVERSE3
Bytecode 0x53
Fee 0.00000002 GAS
Function Reverse the order of the top 3 items on the stack.

REVERSE4

Instruction REVERSE4
Bytecode 0x54
Fee 0.00000002 GAS
Function Reverse the order of the top 4 items on the stack.

REVERSEN

Instruction REVERSEN
Bytecode 0x55
Fee 0.00000016 GAS
Function Gets the integer N from the top stack, and reverse the order of the top N items on the stack.

Slot

INITSSLOT

Instruction INITSSLOT
Bytecode 0x56
Fee 0.00000016 GAS
Function Initialize the static field list for the current execution context.

INITSLOT

Instruction INITSLOT
Bytecode 0x57
Fee 0.00000064 GAS
Function Initialize the argument slot and the local variable list for the current execution context.

LDSFLDN

Instruction LDSFLD0~LDSFLD6
Bytecode 0x58~0x5E
Fee 0.00000002 GAS
Function Loads the static field at index n onto the evaluation stack, where the n is 0~6。

LDSFLD

Instruction LDSFLD
Bytecode 0x5F
Fee 0.00000002 GAS
Function Loads the static field at a specified index onto the evaluation stack. The index is represented as a 1-byte unsigned integer.

STSFLDN

Instruction STSFLD0~STSFLD6
Bytecode 0x60~0x0x66
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the static field list at index n, where the n is 0~6。

STSFLD

Instruction STSFLD
Bytecode 0x67
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the static field list at a specified index. The index is represented as a 1-byte unsigned integer.

LDLOCN

Instruction LDLOC0~LDLOC6
Bytecode 0x68~0x6E
Fee 0.00000002 GAS
Function Loads the local variable at index n onto the evaluation stack, where the n is 0~6。

LDLOC

Instruction LDLOC
Bytecode 0x6F
Fee 0.00000002 GAS
Function Loads the local variable at a specified index onto the evaluation stack. The index is represented as a 1-byte unsigned integer.

STLOCN

Instruction STLOC0~STLOC6
Bytecode 0x70~0x76
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the local variable list at index n, where the n is 0~6。

STLOC

Instruction STLOC
Bytecode 0x77
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the local variable list at a specified index. The index is represented as a 1-byte unsigned integer.

LDARGN

Instruction LDARG0~LDARG6
Bytecode 0x78~0x7E
Fee 0.00000002 GAS
Function Loads the argument at index n onto the evaluation stack, where the n is 0~6.

LDARG

Instruction LDARG
Bytecode 0x7F
Fee 0.00000002 GAS
Function Loads the argument at a specified index onto the evaluation stack. The index is represented as a 1-byte unsigned integer.

STARGN

Instruction STARG0~STARG6
Bytecode 0x80~0x86
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the argument slot at index n, where the n is 0~6.

STARG

Instruction STARG
Bytecode 0x87
Fee 0.00000002 GAS
Function Stores the value on top of the evaluation stack in the argument slot at a specified index. The index is represented as a 1-byte unsigned integer.

String Operation

NEWBUFFER

Instruction NEWBUFFER
Bytecode 0x88
Fee 0.00000256 GAS
Function Create a new buffer

MEMCPY

Instruction MEMCPY
Bytecode 0x89
Fee 0.00002048 GAS
Function memory copy

CAT

Instruction CAT
Bytecode 0x8B
Fee 0.00002048 GAS
Function Concatenates two strings.

SUBSTR

Instruction SUBSTR
Bytecode 0x8C
Fee 0.00002048 GAS
Function Returns a section of a string.

LEFT

Instruction LEFT
Bytecode 0x8D
Fee 0.00002048 GAS
Function Gets characters in the left of the specified point in a string.

RIGHT

Instruction RIGHT
Bytecode 0x8E
Fee 0.00002048 GAS
Function Gets characters in the right of the specified point in a string.

Logical Operation

INVERT

Instruction INVERT
Bytecode 0x90
Fee 0.00000004 GAS
Function Flips all of the bits in the input.

AND

Instruction AND
Bytecode 0x91
Fee 0.00000008 GAS
Function Boolean and between each bit in the inputs

OR

Instruction OR
Bytecode 0x92
Fee 0.00000008 GAS
Function Boolean or between each bit in the inputs.

XOR

Instruction XOR
Bytecode 0x93
Fee 0.00000008 GAS
Function Boolean exclusive or between each bit in the inputs.

EQUAL

Instruction EQUAL
Bytecode 0x97
Fee 0.00000032 GAS
Function Returns 1 if the inputs are exactly equal, 0 otherwise.

NOTEQUAL

Instruction NOTEQUAL
Bytecode 0x98
Fee 0.00000032 GAS
Function Returns 1 if the inputs are not equal, 0 otherwise.

Arithmetic Operation

SIGN

Instruction SIGN
Bytecode 0x99
Fee 0.00000004 GAS
Function Puts the sign of top stack item on top of the main stack. If value is negative, put -1; if positive, put 1; if value is zero, put 0.

ABS

Instruction ABS
Bytecode 0x9A
Fee 0.00000004 GAS
Function The input is made positive.

NEGATE

Instruction NEGATE
Bytecode 0x9B
Fee 0.00000004 GAS
Function The sign of the input is flipped.

INC

Instruction INC
Bytecode 0x9C
Fee 0.00000004 GAS
Function 1 is added to the input.

DEC

Instruction DEC
Bytecode 0x9D
Fee 0.00000004 GAS
Function 1 is subtracted from the input.

ADD

Instruction ADD
Bytecode 0x9E
Fee 0.00000008 GAS
Function a is added to b.

SUB

Instruction SUB
Bytecode 0x9F
Fee 0.00000008 GAS
Function b is subtracted from a.

MUL

Instruction MUL
Bytecode 0xA0
Fee 0.00000008 GAS
Function a is multiplied by b.

DIV

Instruction DIV
Bytecode 0xA1
Fee 0.00000008 GAS
Function a is divided by b.

MOD

Instruction MOD
Bytecode 0xA2
Fee 0.00000008 GAS
Function Returns the remainder after dividing a by b.

POW

Instruction POW
Bytecode 0xA3
Fee 0.00000064 GAS
Function The result of raising value to the exponent power.

SQRT

Instruction SQRT
Bytecode 0xA4
Fee 0.00000064 GAS
Function Returns the square root of a specified number.

SHL

Instruction SHL
Bytecode 0xA8
Fee 0.00000008 GAS
Function Gets the integer n from the top stack and performs a n-bit left shift operation on the remaining BigInteger on the stack.

SHR

Instruction SHR
Bytecode 0xA9
Fee 0.00000008 GAS
Function Gets the integer n from the top stack and performs a n-bit right shift operation on the remaining BigInteger on the stack.

NOT

Instruction NOT
Bytecode 0xAA
Fee 0.00000004 GAS
Function If the input is 0 or 1, it is flipped. Otherwise the output will be 0.

BOOLAND

Instruction BOOLAND
Bytecode 0xAB
Fee 0.00000008 GAS
Function If both a and b are not 0, the output is 1. Otherwise 0.

BOOLOR

Instruction BOOLOR
Bytecode 0xAC
Fee 0.00000008 GAS
Function If a or b is not 0, the output is 1. Otherwise 0.

NZ

Instruction NZ
Bytecode 0xB1
Fee 0.00000004 GAS
Function Returns 0 if the input is 0. 1 otherwise.

NUMEQUAL

Instruction NUMEQUAL
Bytecode 0xB3
Fee 0.00000008 GAS
Function Returns 1 if the numbers are equal, 0 otherwise.

NUMNOTEQUAL

Instruction NUMNOTEQUAL
Bytecode 0xB4
Fee 0.00000008 GAS
Function Returns 1 if the numbers are not equal, 0 otherwise.

LT

Instruction LT
Bytecode 0xB5
Fee 0.00000008 GAS
Function Returns 1 if a is less than b, 0 otherwise.

LE

Instruction LE
Bytecode 0xB6
Fee 0.00000008 GAS
Function Returns 1 if a is less than or equal to b, 0 otherwise.

GT

Instruction GT
Bytecode 0xB7
Fee 0.00000008 GAS
Function Returns 1 if a is greater than b, 0 otherwise.

GE

Instruction GE
Bytecode 0xB8
Fee 0.00000008 GAS
Function Returns 1 if a is greater than or equal to b, 0 otherwise.

MIN

Instruction MIN
Bytecode 0xB9
Fee 0.00000008 GAS
Function Returns the smaller of a and b.

MAX

Instruction MAX
Bytecode 0xBA
Fee 0.00000008 GAS
Function Returns the larger of a and b.

WITHIN

Instruction WITHIN
Bytecode 0xBB
Fee 0.00000008 GAS
Function Returns 1 if x is within the specified range (left-inclusive), 0 otherwise.

Advanced Data Structure

It has implemented common operations for array, map, struct, etc.

PACKMAP

Instruction PACKMAP
Bytecode 0xBE
Fee 0.00002048 GAS
Function A value n is taken from top of main stack. The next n*2 items on main stack are removed, put inside n-sized map and this map is put on top of the main stack.

PACKSTRUCT

Instruction PACKSTRUCT
Bytecode 0xBF
Fee 0.00002048 GAS
Function A value n is taken from top of main stack. The next n items on main stack are removed, put inside n-sized struct and this struct is put on top of the main stack.

PACK

Instruction PACK
Bytecode 0xC0
Fee 0.00002048 GAS
Function A value n is taken from top of main stack. The next n items on main stack are removed, put inside n-sized array and this array is put on top of the main stack.

UNPACK

Instruction UNPACK
Bytecode 0xC1
Fee 0.00002048 GAS
Function An array is removed from top of the main stack. Its elements are put on top of the main stack (in reverse order) and the array size is also put on main stack.

NEWARRAY0

Instruction NEWARRAY0
Bytecode 0xC2
Fee 0.00000016 GAS
Function An array with size n is put on top of the main stack.

NEWARRAY

Instruction NEWARRAY
Bytecode 0xC3
Fee 0.00000512 GAS
Function A value n is taken from top of main stack. A null-filled array with size n is put on top of the main stack.

NEWARRAY_T

Instruction NEWARRAY_T
Bytecode 0xC4
Fee 0.00000512 GAS
Function An array of type T with size n is put on top of the main stack.

NEWSTRUCT0

Instruction NEWSTRUCT0
Bytecode 0xC5
Fee 0.00000016 GAS
Function A structure with size n and all 0 elements is put on top of the main stack.

NEWSTRUCT

Instruction NEWSTRUCT
Bytecode 0xC6
Fee 0.00000512 GAS
Function A value n is taken from top of main stack. A zero-filled struct with size n is put on top of the main stack.

NEWMAP

Instruction NEWMAP
Bytecode 0xC8
Fee 0.00000008 GAS
Function An empty Map is put on top of the main stack.

SIZE

Instruction SIZE
Bytecode 0xCA
Fee 0.00000004 GAS
Function Gets the size of elements on the top stack.

HASKEY

Instruction HASKEY
Bytecode 0xCB
Fee 0.00000064 GAS
Function An input index n (or key) and an array (Map，Buffer, ByteString) are returned from the top of the main stack. Puts True on top of main stack if n is in the length range of the array (Map，Buffer, ByteString), and False otherwise.

KEYS

Instruction KEYS
Bytecode 0xCC
Fee 0.00000016 GAS
Function Gets all Keys of the map from top of the main stack and constructs a new array with all Key and puts it on top of the main stack.

VALUES

Instruction VALUES
Bytecode 0xCD
Fee 0.00008192 GAS
Function Gets all Values of the elements (Array or Map) from top of the main stack and constructs a new array with all Value and puts it on top of the main stack.

PICKITEM

Instruction PICKITEM
Bytecode 0xCE
Fee 0.00000064 GAS
Function Gets the Nth element in the array of the top stack

APPEND

Instruction APPEND
Bytecode 0xCF
Fee 0.00008192 GAS
Function Adds a new item to the arry of the top stack

SETITEM

Instruction SETITEM
Bytecode 0xD0
Fee 0.00008192 GAS
Function Assigns a value to the specified index of element （Array，Map or Buffer）in the top stack

REVERSEITEMS

Instruction REVERSEITEMS
Bytecode 0xD1
Fee 0.00008192 GAS
Function Reverses the elements in Array or Buffer from the top stack.

REMOVE

Instruction REMOVE
Bytecode 0xD2
Fee 0.00000016 GAS
Function Removes the specified index or Key elements from Array or Map

CLEARITEMS

Instruction CLEARITEMS
Bytecode 0xD3
Fee 0.00000016 GAS
Function Remove all the items from the compound-type.

POPITEM

Instruction POPITEM
Bytecode 0xD4
Fee 0.00000016 GAS
Function Pops the last element in Array from the stack top and push into the stack.

Type

ISNULL

Instruction ISNULL
Bytecode 0xD8
Fee 0.00000002 GAS
Function Returns true if the input is null. Returns false otherwise.

ISTYPE

Instruction ISTYPE
Bytecode 0xD9
Fee 0.00000002 GAS
Function Returns true if the top item is of the specified type.

CONVERT

Instruction CONVERT
Bytecode 0xDB
Fee 0.00002048 GAS
Function Converts the top item to the specified type.

Note

The operation code with * indicates that the result of the operation is not pushed back to the EvaluationStack using PUSH().