Bytecode proof in appliedzkp zkevm (9)

1. introduction

bytecode proof Can help EVM proof, bring bytecode Easier to access （bytecode With its code hash To mark ）.bytecode Each of the byte It can be used in the bytecode To access . At the same time, a flag To mark the byte It's a opcode still To the previous PUSH The directive 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 be used for find how many bytes an opcode pushes, Used to detect which byte yes code, Which one? byte No code.

Because it will be for each byte Conduct lookup, The table It can also be used indirectly for 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

The circuit By setting tag = Length add to bytecode length The line of Start , Then from position 0 Start , Traversing this bytecode All of the bytes.

Reference material

[1] zkevm-specs Bytecode Proof