User talk:Smtp

opcode overview

For each opcode is given: its nemonic without the leading OP_, its hexadecimal byte value, the number of stack items needed (poped) during execution, the number of stack items pushed (after execution). A * after the needed stack items indicates that further bytes from the script following the current opcode are needed. A # indicates that items on the alternative stack are poped/pushed. A @ indicates that further (global) data from transcations is needed.
Different colors indicate different semantic execution groups of opcodes.

_FALSE 0x00 0 ; 1(0)

- 0x01 0 *; 1(1)

- 0x02 0 *; 1(2)

- 0x03 0 *; 1(3)

- 0x04 0 *; 1(4)

- 0x04 0 *; 1(5)

- 0x06 0 *; 1(6)

- 0x07 0 *; 1(7)

- 0x08 0 *; 1(8)

- 0x09 0 *; 1(9)

- 0x0a 0 *; 1(10)

- 0x0b 0 *; 1(11)

- 0x0c 0 *; 1(12)

- 0x0d 0 *; 1(13)

- 0x0e 0 *; 1(14)

- 0x0f 0 *; 1(15)

- 0x10 0 *; 1(16)

- 0x11 0 *; 1(17)

- 0x12 0 *; 1(18)

- 0x13 0 *; 1(19)

- 0x14 0 *; 1(20)

- 0x15 0 *; 1(21)

- 0x16 0 *; 1(22)

- 0x17 0 *; 1(23)

- 0x18 0 *; 1(24)

- 0x19 0 *; 1(25)

- 0x1a 0 *; 1(26)

- 0x1b 0 *; 1(27)

- 0x1c 0 *; 1(28)

- 0x1d 0 *; 1(29)

- 0x1e 0 *; 1(30)

- 0x1f 0 *; 1(31)

- 0x20 0 *; 1(32)

- 0x21 0 *; 1(33)

- 0x22 0 *; 1(34)

- 0x23 0 *; 1(35)

- 0x24 0 *; 1(36)

- 0x25 0 *; 1(37)

- 0x26 0 *; 1(38)

- 0x27 0 *; 1(39)

- 0x28 0 *; 1(40)

- 0x29 0 *; 1(41)

- 0x2a 0 *; 1(42)

- 0x2b 0 *; 1(43)

- 0x2c 0 *; 1(44)

- 0x2d 0 *; 1(45)

- 0x2e 0 *; 1(46)

- 0x2f 0 *; 1(47)

- 0x30 0 *; 1(48)

- 0x31 0 *; 1(49)

- 0x32 0 *; 1(50)

- 0x33 0 *; 1(51)

- 0x34 0 *; 1(52)

- 0x35 0 *; 1(53)

- 0x36 0 *; 1(54)

- 0x37 0 *; 1(55)

- 0x38 0 *; 1(56)

- 0x39 0 *; 1(57)

- 0x3a 0 *; 1(58)

- 0x3b 0 *; 1(59)

- 0x3c 0 *; 1(60)

- 0x3d 0 *; 1(61)

- 0x3e 0 *; 1(62)

- 0x3f 0 *; 1(63)

- 0x40 0 *; 1(64)

- 0x41 0 *; 1(65)

- 0x42 0 *; 1(66)

- 0x43 0 *; 1(67)

- 0x44 0 *; 1(68)

- 0x45 0 *; 1(69)

- 0x46 0 *; 1(70)

- 0x47 0 *; 1(71)

- 0x48 0 *; 1(72)

- 0x49 0 *; 1(73)

- 0x4a 0 *; 1(74)

- 0x4b 0 *; 1(75)

_PUSHDATA1 0x4c 0 *; 1(0 - 255)

_PUSHDATA2 0x4d 0 *; 1(0 - 2^16-1)

_PUSHDATA4 0x4e 0 *; 1(0 - 2^32-1)

_1NEGATE 0x4f 0 ; 1(1)

_RESERVED 0x50

_1 0x51 0 ; 1(1)

_2 0x52 0 ; 1(1)

_3 0x53 0 ; 1(1)

_4 0x54 0 ; 1(1)

_5 0x55 0 ; 1(1)

_6 0x56 0 ; 1(1)

_7 0x57 0 ; 1(1)

_8 0x58 0 ; 1(1)

_9 0x59 0 ; 1(1)

_10 0x5a 0 ; 1(1)

_11 0x5b 0 ; 1(1)

_12 0x5c 0 ; 1(1)

_13 0x5d 0 ; 1(1)

_14 0x5e 0 ; 1(1)

_15 0x5f 0 ; 1(1)

_16 0x60 0 ; 1(1)

_NOP 0x61 0 ; 0

_VER 0x62

_IF 0x63 1 ; 0

_NOTIF 0x64 1 ; 0

_VERIF 0x65

_VERNOTIF 0x66

_ELSE 0x67 0 ; 0

_ENDIF 0x68 0 ; 0

_VERIFY 0x69 1 ; 0/1

_RETURN 0x6a 0 ; 0

_TOALTSTACK 0x6b 1 ; 0

_FROMALTSTACK 0x6c 0 #; 1

_2DROP 0x6d 2 ; 0

_2DUP 0x6e 2 ; 4

_3DUP 0x6f 3 ; 6

_2OVER 0x70 4 ; 6

_2ROT 0x71 6 ; 6

_2SWAP 0x72 4 ; 4

_IFDUP 0x73 1 ; 1/2

_DEPTH 0x74 0 ; 1

_DROP 0x75 1 ; 0

_DUP 0x76 1 ; 2

_NIP 0x77 2 ; 1

_OVER 0x78 2 ; 3

_PICK 0x79 1+n+1 ; n+2

_ROLL 0x7a 1+n+1 ; n+1

_ROT 0x7b 3 ; 3

_SWAP 0x7c 2 ; 2

_TUCK 0x7d 2 ; 3

_CAT 0x7e 2 ; 1

_SUBSTR 0x7f 3 ; 1

_LEFT 0x80 2 ; 1

_RIGHT 0x81 2 ; 1

_SIZE 0x82 1 ; 2

_INVERT 0x83 1 ; 1

_AND 0x84 2 ; 1

_OR 0x85 2 ; 1

_XOR 0x86 2 ; 1

_EQUAL 0x87 2 ; 1

_EQUALVERIFY 0x88 2 ; 0/1

_RESERVED1 0x89

_RESERVED2 0x8a

_1ADD 0x8b 1 ; 1

_1SUB 0x8c 1 ; 1

_2MUL 0x8d 1 ; 1

_2DIV 0x8e 1 ; 1

_NEGATE 0x8f 1 ; 1

_ABS 0x90 1 ; 1

_NOT 0x91 1 ; 1

_0NOTEQUAL 0x92 1 ; 1

_ADD 0x93 2 ; 1

_SUB 0x94 2 ; 1

_MUL 0x95 2 ; 1

_DIV 0x96 2 ; 1

_MOD 0x97 2 ; 1

_LSHIFT 0x98 2 ; 1

_RSHIFT 0x99 2 ; 1

_BOOLAND 0x9a 2 ; 1

_BOOLOR 0x9b 2 ; 1

_NUMEQUAL 0x9c 2 ; 1

_NUMEQUALVERIFY 0x9d 2 ; 0/1

_NUMNOTEQUAL 0x9e 2 ; 1

_LESSTHAN 0x9f 2 ; 1

_GREATERTHAN 0xa0 2 ; 1

_LESSTHANOREQUAL 0xa1 2 ; 1

_GREATERTHANOREQUAL 0xa2 2 ; 1

_MIN 0xa3 2 ; 1

_MAX 0xa4 2 ; 1

_WITHIN 0xa5 3 ; 1

_RIPEMD160 0xa6 1 ; 1

_SHA1 0xa7 1 ; 1

_SHA256 0xa8 1 ; 1

_HASH160 0xa9 1 ; 1

_HASH256 0xaa 1 ; 1

_CODESEPARATOR 0xab 0 ; 0

_CHECKSIG 0xac 2 @; 1

_CHECKSIGVERIFY 0xad 2 @; 0/1

_CHECKMULTISIG 0xae 2n+2 @; 1

_CHECKMULTISIGVERIFY 0xaf 2n+2 @; 0/1

_NOP1 0xb0 0 ; 0

_NOP2 0xb1 0 ; 0

_NOP3 0xb2 0 ; 0

_NOP4 0xb3 0 ; 0

_NOP5 0xb4 0 ; 0

_NOP6 0xb5 0 ; 0

_NOP7 0xb6 0 ; 0

_NOP8 0xb7 0 ; 0

_NOP9 0xb8 0 ; 0

_NOP10 0xb9 0 ; 0

- 0xba

- 0xbb

- 0xbc

- 0xbd

- 0xbe

- 0xbf

- 0xc0

- 0xc1

- 0xc2

- 0xc3

- 0xc4

- 0xc5

- 0xc6

- 0xc7

- 0xc8

- 0xc9

- 0xca

- 0xcb

- 0xcc

- 0xcd

- 0xce

- 0xcf

- 0xd0

- 0xd1

- 0xd2

- 0xd3

- 0xd4

- 0xd5

- 0xd6

- 0xd7

- 0xd8

- 0xd9

- 0xda

- 0xdb

- 0xdc

- 0xdd

- 0xde

- 0xdf

- 0xe0

- 0xe1

- 0xe2

- 0xe3

- 0xe4

- 0xe5

- 0xe6

- 0xe7

- 0xe8

- 0xe9

- 0xea

- 0xeb

- 0xec

- 0xed

- 0xee

- 0xef

- 0xf0

- 0xf1

- 0xf2

- 0xf3

- 0xf4

- 0xf5

- 0xf6

- 0xf7

- 0xf8

- 0xf9

- 0xfa

_SMALLINTEGER 0xfb

_PUBKEYS 0xfc

_PUBKEYHASH 0xfd

_PUBKEY 0xfe

_INVALIDOPCODE 0xff

The opcode value 0x00 with nemonic OP_FALSE is also named OP_0 and the opcode value 0x51 with nemonic OP_1 as also named OP_TRUE.

opcode descriptions =

It follows for each opcode less than decimal 185 (hexa 0xba) a description for its usage.

Constants

Nemonic	Decimal	Hex	Input	Output	Description
OP_FALSE, OP_0	0	0x00	Nothing	(empty string)	A byte vector of length 0 is pushed onto the stack. (Thus, it is not a no-op!)
(no official nemonics)	1 - 75	0x01 - 0x4b	(operands)	data	The next opcode-many bytes is data to be pushed onto the stack.
OP_PUSHDATA1	76	0x4c	(operands)	data	The next byte contains the number of bytes to be pushed onto the stack which follow this byte.
OP_PUSHDATA2	77	0x4d	(operands)	data	The next two bytes contain the number of bytes to be pushed onto the stack which follow theses 2 bytes.
OP_PUSHDATA4	78	0x4e	(operands)	data	The next four bytes contain the number of bytes to be pushed onto the stack which follow theses 4 bytes.
OP_1NEGATE	79	0x4f	Nothing	-1	The number -1 is pushed onto the stack.
OP_1, OP_TRUE	81	0x51	Nothing	1	The number 1 is pushed onto the stack.
OP_2 - OP_16	82 - 96	0x52 - 0x60	Nothing	2-16	The value <opcode>-80 (thus, one of 2 - 16) is pushed onto the stack.

Flow control

Nemonic	Decimal	Hex	Input	Output	Description
OP_NOP	97	0x61	Nothing	Nothing	Does nothing.
OP_IF	99	0x63	Boolean	Nothing	If the top stack value is not 0, the statements are executed. The top stack value is removed. Lead in a logcial <value> then [statements] [else [statements]] endif expression
OP_NOTIF	100	0x64	Boolean	Nothing	If the top stack value is 0, the statements are executed. The top stack value is removed. Lead in a logcial <value> then [statements] [else [statements]] endif expression
OP_ELSE	103	0x67	Nothing	Nothing	If the preceding OP_IF or OP_NOTIF or OP_ELSE was not executed then these statements are and if the preceding OP_IF or OP_NOTIF or OP_ELSE was executed then these statements are not.
OP_ENDIF	104	0x68	Nothing	Nothing	Ends a logcial If <value> then [statements] [else [statements]] expression
OP_VERIFY	105	0x69	Boolean	Nothing / False	If top stack value is not true then marks transaction as invalid . A value true is removed, but false is not.
OP_RETURN	106	0x6a	Nothing	Nothing	Marks transaction as invalid.

Stack

Nemonic	Decimal	Hex	Input	Output	Description
OP_TOALTSTACK	107	0x6b	x1 (alt)	(alt x1)	Puts the input onto the top of the alt stack. Removes it from the (main) stack.
OP_FROMALTSTACK	108	0x6c	(alt x1)	x1 (alt)	Puts the input onto the top of the (main) stack. Removes it from the alt stack.
OP_IFDUP	115	0x73	x	x / x x	If the top stack value is not 0, duplicate it.
OP_DEPTH	116	0x74	Nothing	<Stack size>	Puts the number of stack items onto the stack as one hexadecimal coded little-endian byte-vector
OP_DROP	117	0x75	x	Nothing	Removes the top stack item.
OP_DUP	118	0x76	x	x x	Duplicates the top stack item.
OP_NIP	119	0x77	x1 x2	x2	Removes the second-to-top stack item.
OP_OVER	120	0x78	x1 x2	x1 x2 x1	Copies the second-to-top stack item to the top.
OP_PICK	121	0x79	xn ... x2 x1 x0 <n>	xn ... x2 x1 x0 xn	The item n back in the stack is copied to the top.
OP_ROLL	122	0x7a	xn ... x2 x1 x0 <n>	... x2 x1 x0 xn	The item n back in the stack is moved to the top.
OP_ROT	123	0x7b	x1 x2 x3	x2 x3 x1	The top three items on the stack are rotated to the left.
OP_SWAP	124	0x7c	x1 x2	x2 x1	The top two items on the stack are swapped.
OP_TUCK	125	0x7d	x1 x2	x2 x1 x2	The item at the top of the stack is copied and inserted before the second-to-top item.
OP_2DROP	109	0x6d	x1 x2	Nothing	Removes the top two stack items.
OP_2DUP	110	0x6e	x1 x2	x1 x2 x1 x2	Duplicates the top two stack items.
OP_3DUP	111	0x6f	x1 x2 x3	x1 x2 x3 x1 x2 x3	Duplicates the top three stack items.
OP_2OVER	112	0x70	x1 x2 x3 x4	x1 x2 x3 x4 x1 x2	Copies the pair of items two spaces back in the stack to the front.
OP_2ROT	113	0x71	x1 x2 x3 x4 x5 x6	x3 x4 x5 x6 x1 x2	The fifth and sixth items back are moved to the top of the stack.
OP_2SWAP	114	0x72	x1 x2 x3 x4	x3 x4 x1 x2	Swaps the top two pairs of items.

Splice

Nemonic	Decimal	Hex	Input	Output	Description
OP_CAT	126	0x7e	x1 x2	out	Concatenates two strings resp. byte vectors. Currently disabled.
OP_SUBSTR	127	0x7f	x index size	out	Returns the section started at position <index> and of length <size> of a string resp. byte vector. Currently disabled.
OP_LEFT	128	0x80	x index	out	Keeps only characters left of the specified point in a string. Currently disabled.
OP_RIGHT	129	0x81	x index	out	Keeps only characters right of the specified point in a string. Currently disabled.
OP_SIZE	130	0x82	x	x size	Returns the length of the input string resp. byte vector resp. stack item.

Bitwise logic

Nemonic	Decimal	Hex	Input	Output	Description
OP_INVERT	131	0x83	in	out	Flips all of the bits in the input. Currently disabled.
OP_AND	132	0x84	x1 x2	out	Boolean and between each bit in the inputs. Currently disabled.
OP_OR	133	0x85	x1 x2	out	Boolean or between each bit in the inputs. Currently disabled.
OP_XOR	134	0x86	x1 x2	out	Boolean exclusive or between each bit in the inputs. Currently disabled.
OP_EQUAL	135	0x87	x1 x2	Boolean	Returns 1 if the inputs are byte-wise equal, 0 otherwise.
OP_EQUALVERIFY	136	0x88	x1 x2	Nothing / false	Same as OP_EQUAL, but runs OP_VERIFY afterward.

Arithmetic

(In very early versions, the implemented arithmetic opcodes were limited to maximal 4 byte vectors.)

Nemonic	Decimal	Hex	Input	Output	Description
OP_1ADD	139	0x8b	in	out	1 is added to the input.
OP_1SUB	140	0x8c	in	out	1 is subtracted from the input.
OP_2MUL	141	0x8d	in	out	The input is multiplied by 2. Currently disabled.
OP_2DIV	142	0x8e	in	out	The input is divided by 2. Currently disabled.
OP_NEGATE	143	0x8f	in	out	The sign of the input is flipped.
OP_ABS	144	0x90	in	out	The input is made positive.
OP_NOT	145	0x91	in	Boolean	If the input is 0 or 1, it is flipped. Otherwise the output will be 0.
OP_0NOTEQUAL	146	0x92	in	Boolean	Returns 0 if the input is 0. 1 otherwise.
OP_ADD	147	0x93	a b	out	a is added to b.
OP_SUB	148	0x94	a b	out	b is subtracted from a.
OP_MUL	149	0x95	a b	out	a is multiplied by b. Currently disabled.
OP_DIV	150	0x96	a b	out	a is divided by b (b should be not 0). Currently disabled.
OP_MOD	151	0x97	a b	out	Returns the remainder after dividing a by b. Currently disabled.
OP_LSHIFT	152	0x98	a b	out	Shifts a left b bits, preserving sign. Currently disabled.
OP_RSHIFT	153	0x99	a b	out	Shifts a right b bits, preserving sign. Currently disabled.
OP_BOOLAND	154	0x9a	a b	Boolean	If both a and b are not 0, the output is 1. Otherwise 0.
OP_BOOLOR	155	0x9b	a b	Boolean	If a or b is not 0, the output is 1. Otherwise 0.
OP_NUMEQUAL	156	0x9c	a b	Boolean	Returns 1 if the numbers are equal, 0 otherwise.
OP_NUMEQUALVERIFY	157	0x9d	a b	Nothing / False	Same as OP_NUMEQUAL, but runs OP_VERIFY afterward.
OP_NUMNOTEQUAL	158	0x9e	a b	Boolean	Returns 1 if the numbers are not equal, 0 otherwise.
OP_LESSTHAN	159	0x9f	a b	Boolean	Returns 1 if a is less than b, 0 otherwise.
OP_GREATERTHAN	160	0xa0	a b	Boolean	Returns 1 if a is greater than b, 0 otherwise.
OP_LESSTHANOREQUAL	161	0xa1	a b	Boolean	Returns 1 if a is less than or equal to b, 0 otherwise.
OP_GREATERTHANOREQUAL	162	0xa2	a b	Boolean	Returns 1 if a is greater than or equal to b, 0 otherwise.
OP_MIN	163	0xa3	a b	a / b	Returns the smaller of a and b.
OP_MAX	164	0xa4	a b	a / b	Returns the larger of a and b.
OP_WITHIN	165	0xa5	x min max	Boolean	Returns 1 if x is within the specified range (left-inclusive) , 0 otherwise. min may be greater than max

Crypto

Nemonic	Decimal	Hex	Input	Output	Description
OP_RIPEMD160	166	0xa6	x	hash20	The input is hashed using RIPEMD-160.
OP_SHA1	167	0xa7	x	hash20	The input is hashed using SHA-1.
OP_SHA256	168	0xa8	x	hash32	The input is hashed using SHA-256.
OP_HASH160	169	0xa9	x	hash20	The input is hashed twice: first with SHA-256 and then with RIPEMD-160.
OP_HASH256	170	0xaa	x	hash32	The input is hashed two times with SHA-256.
OP_CODESEPARATOR	171	0xab	Nothing	Nothing	All of the signature checking opcodes will only match signatures to the data after the most recently-executed OP_CODESEPARATOR.
OP_CHECKSIG	172	0xac	sig pubkey	Boolean	The entire transaction's outputs, inputs, and script (from the most recently-executed OP_CODESEPARATOR to the end) are hashed. The signature used by OP_CHECKSIG must be a valid signature for this hash and public key. If it is, 1 is returned, 0 otherwise.
OP_CHECKSIGVERIFY	173	0xad	sig pubkey	Nothing / False	Same as OP_CHECKSIG, but OP_VERIFY is executed afterward.
OP_CHECKMULTISIG	174	0xae	sig1 sig2 ... <number of signatures> pub1 pub2 <number of public keys>	Boolean	For each signature and public key pair, OP_CHECKSIG is executed. If more public keys than signatures are listed, some key/sig pairs can fail. All signatures need to match a public key. If all signatures are valid, 1 is returned, 0 otherwise. Due to a bug, one extra unused value is removed from the stack.
OP_CHECKMULTISIGVERIFY	175	0xaf	sig1 sig2 ... <number of signatures> pub1 pub2 ... <number of public keys>	Nothing / False	Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward.

Pseudo-opcodes

These nemonics are used internally for assisting with transaction matching. They are invalid if used in actual scripts.

Nemonic	Decimal	Hex	Description
OP_PUBKEYHASH	253	0xfd	Represents a public key hashed with OP_HASH160.
OP_PUBKEY	254	0xfe	Represents a public key compatible with OP_CHECKSIG.
OP_INVALIDOPCODE	255	0xff	Matches any opcode that is not yet assigned.

Reserved opcodes

Nemonic	Decimal	Hex	Description
OP_RESERVED	80	0x50	Transaction is invalid unless occuring in an unexecuted OP_IF branch
OP_VER	98	0x62	Transaction is invalid unless occuring in an unexecuted OP_IF branch
OP_VERIF	101	0x65	Transaction is invalid even when occuring in an unexecuted OP_IF branch
OP_VERNOTIF	102	0x66	Transaction is invalid even when occuring in an unexecuted OP_IF branch
OP_RESERVED1	137	0x89	Transaction is invalid unless occuring in an unexecuted OP_IF branch
OP_RESERVED2	138	0x8a	Transaction is invalid unless occuring in an unexecuted OP_IF branch

Each opcode not assigned (currently also every opcode value > 185) is also reserved. Using an unassigned opcode makes the transaction invalid.

Transparent opcodes

Nemonic	Decimal	Hex	Description
OP_NOP1-OP_NOP10	176-185	0xb0-0xb9	The opcode has no effect.

script validation conditions

A script is considered invalid, if any of these conditions meets:

• the total size of the script exceeds (currently) 10000 bytes
• there are more than (currently) 201 opcodes of opcode value > 0x60 in the script
• each instruction is (currently) limited to maximal 520 bytes. This effects only the opcodes OP_PUSHDATA2 and OP_PUSHDATA4
• the executed opcode of the script has insufficient input (from stack, from script or from anywhere)
• the opcode is not defined (for execution) - indicated by white or light gray background color in the table
• the opcode is disabled (currently 15 opcodes) - indicated by white fontcolor in the above table
• stack overflow occurs during execution of the opcode (currently the number of items on the stack and on the alternate stack is limited to 1000)
• the opcodes OP_VERIF and OP_NOTVERIF invalidate a script which contains this opcode (even if this opcode is not executed!)
• the opcodes OP_ELSE or OP_ENDIF has no matching OP_IF
  
• the script execution has been finished but there is (at least) an unmatched OP_IF
  
• the opcodes OP_VERIFY, OP_EQUALVERIFY, OP_NUMEQUALVERIFY, OP_CHECKSIGVERIFY and OP_CHECKMULTISIGVERIFY invalidate the script if the stack-top item is false
• the execution of OP_RETURN
• the numerical value of the top-stack item is negative or greater than the number of items - 2 on the stack if OP_PICK or OP_ROLL shall be executed
• (the 2nd argument of OP_WITHIN is numerical greater than the top-stack item)
• an item used as pubkey or signature for each of the opcodes OP_CHECKSIG, OP_CHECKSIGVERIFY, OP_CHECKMULTISIG or OP_CHECKMULTISIGVERIFY can be neither a pubkey or signature (for the given hash)
• the number of signature items or the number of public key items on the stack is negative for OP_CHECKMULTISIG or OP_CHECKMULTISIGVERIFY
• there or more signatures items than public key items on the stack for OP_CHECKMULTISIG or OP_CHECKMULTISIGVERIFY
• there are (currently) more than 20 public key items on the stack for OP_CHECKMULTISIG or CHECKMULTISIGVERIFY
• the script execution has been finished and the stack is empty or the top-stack item is false (numerical value 0)

else the script is considered to be valid.

References

http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.7.1/ | bitcoin-clinet version 0.7.1 source-file src/src/script.cpp