ethereum.forks.homestead.vm.instructions.stack

Ethereum Virtual Machine (EVM) Stack Instructions.

.. contents:: Table of Contents :backlinks: none :local:

Introduction

Implementations of the EVM stack related instructions.

pop

Remove item from stack.

Parameters

evm : The current EVM frame.

def pop(​evm: Evm​) -> None:
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    """
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    Remove item from stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    stack.pop(evm.stack)
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    pass
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    # PROGRAM COUNTER
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    evm.pc += Uint(1)

push_n

Pushes a N-byte immediate onto the stack.

Parameters

evm : The current EVM frame.

num_bytes : The number of immediate bytes to be read from the code and pushed to the stack.

def push_n(​evm: Evm, ​​num_bytes: int​) -> None:
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    """
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    Pushes a N-byte immediate onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    num_bytes :
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        The number of immediate bytes to be read from the code and pushed to
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        the stack.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_VERY_LOW)
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    # OPERATION
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    data_to_push = U256.from_be_bytes(
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        buffer_read(evm.code, U256(evm.pc + Uint(1)), U256(num_bytes))
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    )
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    stack.push(evm.stack, data_to_push)
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    # PROGRAM COUNTER
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    evm.pc += Uint(1) + Uint(num_bytes)

dup_n

Duplicate the Nth stack item (from top of the stack) to the top of stack.

Parameters

evm : The current EVM frame.

item_number : The stack item number (0-indexed from top of stack) to be duplicated to the top of stack.

def dup_n(​evm: Evm, ​​item_number: int​) -> None:
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    """
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    Duplicate the Nth stack item (from top of the stack) to the top of stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    item_number :
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        The stack item number (0-indexed from top of stack) to be duplicated
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        to the top of stack.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_VERY_LOW)
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    if item_number >= len(evm.stack):
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        raise StackUnderflowError
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    data_to_duplicate = evm.stack[len(evm.stack) - 1 - item_number]
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    stack.push(evm.stack, data_to_duplicate)
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    # PROGRAM COUNTER
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    evm.pc += Uint(1)

swap_n

Swap the top and the item_number element of the stack, where the top of the stack is position zero.

If item_number is zero, this function does nothing (which should not be possible, since there is no SWAP0 instruction).

Parameters

evm : The current EVM frame.

item_number : The stack item number (0-indexed from top of stack) to be swapped with the top of stack element.

def swap_n(​evm: Evm, ​​item_number: int​) -> None:
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    """
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    Swap the top and the `item_number` element of the stack, where
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    the top of the stack is position zero.
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    If `item_number` is zero, this function does nothing (which should not be
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    possible, since there is no `SWAP0` instruction).
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    item_number :
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        The stack item number (0-indexed from top of stack) to be swapped
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        with the top of stack element.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_VERY_LOW)
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    if item_number >= len(evm.stack):
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        raise StackUnderflowError
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    evm.stack[-1], evm.stack[-1 - item_number] = (
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        evm.stack[-1 - item_number],
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        evm.stack[-1],
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    )
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    # PROGRAM COUNTER
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    evm.pc += Uint(1)

push1

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push1 = partial(push_n, num_bytes=1)

push2

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push2 = partial(push_n, num_bytes=2)

push3

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push3 = partial(push_n, num_bytes=3)

push4

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push4 = partial(push_n, num_bytes=4)

push5

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push5 = partial(push_n, num_bytes=5)

push6

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push6 = partial(push_n, num_bytes=6)

push7

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push7 = partial(push_n, num_bytes=7)

push8

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push8 = partial(push_n, num_bytes=8)

push9

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push9 = partial(push_n, num_bytes=9)

push10

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push10 = partial(push_n, num_bytes=10)

push11

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push11 = partial(push_n, num_bytes=11)

push12

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push12 = partial(push_n, num_bytes=12)

push13

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push13 = partial(push_n, num_bytes=13)

push14

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push14 = partial(push_n, num_bytes=14)

push15

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push15 = partial(push_n, num_bytes=15)

push16

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push16 = partial(push_n, num_bytes=16)

push17

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push17 = partial(push_n, num_bytes=17)

push18

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push18 = partial(push_n, num_bytes=18)

push19

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push19 = partial(push_n, num_bytes=19)

push20

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push20 = partial(push_n, num_bytes=20)

push21

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push21 = partial(push_n, num_bytes=21)

push22

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push22 = partial(push_n, num_bytes=22)

push23

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push23 = partial(push_n, num_bytes=23)

push24

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push24 = partial(push_n, num_bytes=24)

push25

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push25 = partial(push_n, num_bytes=25)

push26

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push26 = partial(push_n, num_bytes=26)

push27

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push27 = partial(push_n, num_bytes=27)

push28

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push28 = partial(push_n, num_bytes=28)

push29

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push29 = partial(push_n, num_bytes=29)

push30

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push30 = partial(push_n, num_bytes=30)

push31

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push31 = partial(push_n, num_bytes=31)

push32

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push32 = partial(push_n, num_bytes=32)

dup1

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dup1 = partial(dup_n, item_number=0)

dup2

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dup2 = partial(dup_n, item_number=1)

dup3

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dup3 = partial(dup_n, item_number=2)

dup4

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dup4 = partial(dup_n, item_number=3)

dup5

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dup5 = partial(dup_n, item_number=4)

dup6

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dup6 = partial(dup_n, item_number=5)

dup7

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dup7 = partial(dup_n, item_number=6)

dup8

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dup8 = partial(dup_n, item_number=7)

dup9

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dup9 = partial(dup_n, item_number=8)

dup10

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dup10 = partial(dup_n, item_number=9)

dup11

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dup11 = partial(dup_n, item_number=10)

dup12

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dup12 = partial(dup_n, item_number=11)

dup13

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dup13 = partial(dup_n, item_number=12)

dup14

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dup14 = partial(dup_n, item_number=13)

dup15

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dup15 = partial(dup_n, item_number=14)

dup16

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dup16 = partial(dup_n, item_number=15)

swap1

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swap1 = partial(swap_n, item_number=1)

swap2

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swap2 = partial(swap_n, item_number=2)

swap3

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swap3 = partial(swap_n, item_number=3)

swap4

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swap4 = partial(swap_n, item_number=4)

swap5

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swap5 = partial(swap_n, item_number=5)

swap6

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swap6 = partial(swap_n, item_number=6)

swap7

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swap7 = partial(swap_n, item_number=7)

swap8

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swap8 = partial(swap_n, item_number=8)

swap9

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swap9 = partial(swap_n, item_number=9)

swap10

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swap10 = partial(swap_n, item_number=10)

swap11

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swap11 = partial(swap_n, item_number=11)

swap12

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swap12 = partial(swap_n, item_number=12)

swap13

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swap13 = partial(swap_n, item_number=13)

swap14

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swap14 = partial(swap_n, item_number=14)

swap15

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swap15 = partial(swap_n, item_number=15)

swap16

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swap16 = partial(swap_n, item_number=16)