> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# pushBytes()

> Get number of immediate bytes for PUSH opcode

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## Opcode.pushBytes()

Get number of immediate bytes for PUSH opcode.

<Tabs>
  <Tab title="Functional API">
    ```typescript theme={null}
    import { pushBytes, PUSH1, PUSH32 } from 'tevm/Opcode'

    pushBytes(PUSH1)   // 1
    pushBytes(PUSH32)  // 32
    ```
  </Tab>
</Tabs>

## Parameters

* `opcode: BrandedOpcode` - Opcode to check

## Returns

`number | undefined` - Byte count (0-32) or undefined if not PUSH

## PUSH Byte Counts

```typescript theme={null}
PUSH0:  0 bytes  (0x5F)
PUSH1:  1 byte   (0x60)
PUSH2:  2 bytes  (0x61)
PUSH3:  3 bytes  (0x62)
...
PUSH31: 31 bytes (0x7E)
PUSH32: 32 bytes (0x7F)
```

## Use Cases

### Skip PUSH Data During Parsing

```typescript theme={null}
function parseBytecode(bytecode: Uint8Array): void {
  let i = 0
  while (i < bytecode.length) {
    const opcode = bytecode[i]
    console.log(`Offset ${i}: ${Opcode.name(opcode)}`)

    const pushSize = Opcode.pushBytes(opcode)
    if (pushSize !== undefined) {
      i += pushSize  // Skip immediate data
    }
    i++  // Next opcode
  }
}
```

### Validate PUSH Data

```typescript theme={null}
function validatePushData(inst: Instruction): boolean {
  const expected = Opcode.pushBytes(inst.opcode)
  if (expected === undefined) return true  // Not a PUSH

  if (expected === 0) {
    return inst.immediate === undefined  // PUSH0 has no data
  }

  return inst.immediate?.length === expected
}
```

## Related

* [isPush()](/primitives/opcode/is-push) - Check if PUSH opcode
* [pushOpcode()](/primitives/opcode/push-opcode) - Get PUSH opcode for length