1. 引言
bytecode proof可帮助EVM proof，使得bytecode更易于访问（bytecode以其code hash来标识）。bytecode中的每个byte可通过其在该bytecode中的位置来访问。同时标注了一个flag来标识该byte 是一个opcode 还是 给前一PUSH指令的data。
2. Bytecode Circuit Layout
| Column | Description |
|---|---|
q_first |
1 on the first row, else 0 |
q_last |
1 on the last row, else 0 |
hash |
The keccak hash of the bytecode |
tag |
Tag indicates whether value is a byte or length of the bytecode |
index |
The position of the byte in the bytecode |
value |
The byte data for the current position, or length of the bytecode |
is_code |
1 if the byte is code, 0 if the byte is PUSH data |
push_data_left |
The number of PUSH data bytes that still follow the current row |
hash_rlc |
The accumulator containing the current and previous bytes |
hash_length |
The bytecode length |
byte_push_size |
The number of bytes pushed for the current byte |
is_final |
1 if the current byte is the last byte of the bytecode, else 0 |
padding |
1 if the current row is padding, else 0 |
push_data_left_inv |
The inverse of push_data_left (IsZeroChip helper) |
push_table.byte |
Push Table: A byte value |
push_table.push_size |
Push Table: The number of bytes pushed for this byte as opcode |
3. Push lookup table
push lookup table用于find how many bytes an opcode pushes，用于探测哪个byte是code，哪个byte不是code。
由于会对每个byte进行lookup，该table也可间接用于range check the byte inputs。
| Byte | Num bytes pushed |
|---|---|
| [0, OpcodeId::PUSH1] | 0 |
| [OpcodeId::PUSH1, OpcodeId::PUSH32] | [1..32] |
| [OpcodeId::PUSH32, 256] | 0 |
3.1 Circuit behavior
该circuit 以通过设置tag = Length添加bytecode length的行 开始，然后自位置0开始，遍历该bytecode的所有bytes。