# `EEVM.Interpreter.Instructions.Bitwise`
[🔗](https://github.com/mw2000/eevm/blob/v0.1.0/lib/eevm/interpreter/instructions/bitwise.ex#L1)

EVM bitwise opcodes: AND, OR, XOR, NOT, BYTE, SHL, SHR, SAR, CLZ.

# `stack_op`

```elixir
@spec stack_op(non_neg_integer(), [non_neg_integer()]) :: [non_neg_integer()]
```

Applies a bitwise opcode to the stack (a list, top first) and returns the new stack.

| Byte | Mnemonic | Operation                                         |
|------|----------|---------------------------------------------------|
| 0x16 | AND      | bitwise AND of a and b                            |
| 0x17 | OR       | bitwise OR of a and b                             |
| 0x18 | XOR      | bitwise XOR of a and b                            |
| 0x19 | NOT      | bitwise complement (all 256 bits flipped)         |
| 0x1A | BYTE     | byte at index i of x (big-endian, 0 = MSB)        |
| 0x1B | SHL      | logical left shift: x << shift mod 2^256          |
| 0x1C | SHR      | logical right shift: x >> shift                   |
| 0x1D | SAR      | arithmetic right shift (sign-preserving)          |
| 0x1E | CLZ      | count of leading zero bits in x (256 if x = 0)    |

The interpreter has already checked that the stack holds the opcode's inputs.

    iex> EEVM.Interpreter.Instructions.Bitwise.stack_op(0x1B, [4, 1])
    [16]

---

*Consult [api-reference.md](api-reference.md) for complete listing*