ethereum.berlin.vm.instructions.bitwise
Ethereum Virtual Machine (EVM) Bitwise Instructions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. contents:: Table of Contents :backlinks: none :local:
Introduction
Implementations of the EVM bitwise instructions.
bitwise_and
Bitwise AND operation of the top 2 elements of the stack. Pushes the result back on the stack.
Parameters
evm : The current EVM frame.
def bitwise_and(evm: Evm) -> None:
| 23 | """ |
|---|---|
| 24 | Bitwise AND operation of the top 2 elements of the stack. Pushes the |
| 25 | result back on the stack. |
| 26 | |
| 27 | Parameters |
| 28 | ---------- |
| 29 | evm : |
| 30 | The current EVM frame. |
| 31 | |
| 32 | """ |
| 33 | # STACK |
| 34 | x = pop(evm.stack) |
| 35 | y = pop(evm.stack) |
| 36 | |
| 37 | # GAS |
| 38 | charge_gas(evm, GAS_VERY_LOW) |
| 39 | |
| 40 | # OPERATION |
| 41 | push(evm.stack, x & y) |
| 42 | |
| 43 | # PROGRAM COUNTER |
| 44 | evm.pc += Uint(1) |
bitwise_or
Bitwise OR operation of the top 2 elements of the stack. Pushes the result back on the stack.
Parameters
evm : The current EVM frame.
def bitwise_or(evm: Evm) -> None:
| 48 | """ |
|---|---|
| 49 | Bitwise OR operation of the top 2 elements of the stack. Pushes the |
| 50 | result back on the stack. |
| 51 | |
| 52 | Parameters |
| 53 | ---------- |
| 54 | evm : |
| 55 | The current EVM frame. |
| 56 | |
| 57 | """ |
| 58 | # STACK |
| 59 | x = pop(evm.stack) |
| 60 | y = pop(evm.stack) |
| 61 | |
| 62 | # GAS |
| 63 | charge_gas(evm, GAS_VERY_LOW) |
| 64 | |
| 65 | # OPERATION |
| 66 | push(evm.stack, x | y) |
| 67 | |
| 68 | # PROGRAM COUNTER |
| 69 | evm.pc += Uint(1) |
bitwise_xor
Bitwise XOR operation of the top 2 elements of the stack. Pushes the result back on the stack.
Parameters
evm : The current EVM frame.
def bitwise_xor(evm: Evm) -> None:
| 73 | """ |
|---|---|
| 74 | Bitwise XOR operation of the top 2 elements of the stack. Pushes the |
| 75 | result back on the stack. |
| 76 | |
| 77 | Parameters |
| 78 | ---------- |
| 79 | evm : |
| 80 | The current EVM frame. |
| 81 | |
| 82 | """ |
| 83 | # STACK |
| 84 | x = pop(evm.stack) |
| 85 | y = pop(evm.stack) |
| 86 | |
| 87 | # GAS |
| 88 | charge_gas(evm, GAS_VERY_LOW) |
| 89 | |
| 90 | # OPERATION |
| 91 | push(evm.stack, x ^ y) |
| 92 | |
| 93 | # PROGRAM COUNTER |
| 94 | evm.pc += Uint(1) |
bitwise_not
Bitwise NOT operation of the top element of the stack. Pushes the result back on the stack.
Parameters
evm : The current EVM frame.
def bitwise_not(evm: Evm) -> None:
| 98 | """ |
|---|---|
| 99 | Bitwise NOT operation of the top element of the stack. Pushes the |
| 100 | result back on the stack. |
| 101 | |
| 102 | Parameters |
| 103 | ---------- |
| 104 | evm : |
| 105 | The current EVM frame. |
| 106 | |
| 107 | """ |
| 108 | # STACK |
| 109 | x = pop(evm.stack) |
| 110 | |
| 111 | # GAS |
| 112 | charge_gas(evm, GAS_VERY_LOW) |
| 113 | |
| 114 | # OPERATION |
| 115 | push(evm.stack, ~x) |
| 116 | |
| 117 | # PROGRAM COUNTER |
| 118 | evm.pc += Uint(1) |
get_byte
For a word (defined by next top element of the stack), retrieve the Nth byte (0-indexed and defined by top element of stack) from the left (most significant) to right (least significant).
Parameters
evm : The current EVM frame.
def get_byte(evm: Evm) -> None:
| 122 | """ |
|---|---|
| 123 | For a word (defined by next top element of the stack), retrieve the |
| 124 | Nth byte (0-indexed and defined by top element of stack) from the |
| 125 | left (most significant) to right (least significant). |
| 126 | |
| 127 | Parameters |
| 128 | ---------- |
| 129 | evm : |
| 130 | The current EVM frame. |
| 131 | |
| 132 | """ |
| 133 | # STACK |
| 134 | byte_index = pop(evm.stack) |
| 135 | word = pop(evm.stack) |
| 136 | |
| 137 | # GAS |
| 138 | charge_gas(evm, GAS_VERY_LOW) |
| 139 | |
| 140 | # OPERATION |
| 141 | if byte_index >= U256(32): |
| 142 | result = U256(0) |
| 143 | else: |
| 144 | extra_bytes_to_right = U256(31) - byte_index |
| 145 | # Remove the extra bytes in the right |
| 146 | word = word >> (extra_bytes_to_right * U256(8)) |
| 147 | # Remove the extra bytes in the left |
| 148 | word = word & U256(0xFF) |
| 149 | result = word |
| 150 | |
| 151 | push(evm.stack, result) |
| 152 | |
| 153 | # PROGRAM COUNTER |
| 154 | evm.pc += Uint(1) |
bitwise_shl
Logical shift left (SHL) operation of the top 2 elements of the stack. Pushes the result back on the stack. Parameters
evm : The current EVM frame.
def bitwise_shl(evm: Evm) -> None:
| 158 | """ |
|---|---|
| 159 | Logical shift left (SHL) operation of the top 2 elements of the stack. |
| 160 | Pushes the result back on the stack. |
| 161 | Parameters |
| 162 | ---------- |
| 163 | evm : |
| 164 | The current EVM frame. |
| 165 | """ |
| 166 | # STACK |
| 167 | shift = Uint(pop(evm.stack)) |
| 168 | value = Uint(pop(evm.stack)) |
| 169 | |
| 170 | # GAS |
| 171 | charge_gas(evm, GAS_VERY_LOW) |
| 172 | |
| 173 | # OPERATION |
| 174 | if shift < Uint(256): |
| 175 | result = U256((value << shift) & Uint(U256.MAX_VALUE)) |
| 176 | else: |
| 177 | result = U256(0) |
| 178 | |
| 179 | push(evm.stack, result) |
| 180 | |
| 181 | # PROGRAM COUNTER |
| 182 | evm.pc += Uint(1) |
bitwise_shr
Logical shift right (SHR) operation of the top 2 elements of the stack. Pushes the result back on the stack. Parameters
evm : The current EVM frame.
def bitwise_shr(evm: Evm) -> None:
| 186 | """ |
|---|---|
| 187 | Logical shift right (SHR) operation of the top 2 elements of the stack. |
| 188 | Pushes the result back on the stack. |
| 189 | Parameters |
| 190 | ---------- |
| 191 | evm : |
| 192 | The current EVM frame. |
| 193 | """ |
| 194 | # STACK |
| 195 | shift = pop(evm.stack) |
| 196 | value = pop(evm.stack) |
| 197 | |
| 198 | # GAS |
| 199 | charge_gas(evm, GAS_VERY_LOW) |
| 200 | |
| 201 | # OPERATION |
| 202 | if shift < U256(256): |
| 203 | result = value >> shift |
| 204 | else: |
| 205 | result = U256(0) |
| 206 | |
| 207 | push(evm.stack, result) |
| 208 | |
| 209 | # PROGRAM COUNTER |
| 210 | evm.pc += Uint(1) |
bitwise_sar
Arithmetic shift right (SAR) operation of the top 2 elements of the stack. Pushes the result back on the stack. Parameters
evm : The current EVM frame.
def bitwise_sar(evm: Evm) -> None:
| 214 | """ |
|---|---|
| 215 | Arithmetic shift right (SAR) operation of the top 2 elements of the stack. |
| 216 | Pushes the result back on the stack. |
| 217 | Parameters |
| 218 | ---------- |
| 219 | evm : |
| 220 | The current EVM frame. |
| 221 | """ |
| 222 | # STACK |
| 223 | shift = int(pop(evm.stack)) |
| 224 | signed_value = pop(evm.stack).to_signed() |
| 225 | |
| 226 | # GAS |
| 227 | charge_gas(evm, GAS_VERY_LOW) |
| 228 | |
| 229 | # OPERATION |
| 230 | if shift < 256: |
| 231 | result = U256.from_signed(signed_value >> shift) |
| 232 | elif signed_value >= 0: |
| 233 | result = U256(0) |
| 234 | else: |
| 235 | result = U256.MAX_VALUE |
| 236 | |
| 237 | push(evm.stack, result) |
| 238 | |
| 239 | # PROGRAM COUNTER |
| 240 | evm.pc += Uint(1) |