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.

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