logos-storage/plonky2
1
0
Fork 0
mirror of https://github.com/logos-storage/plonky2.git synced 2026-01-03 06:13:07 +00:00
Code Issues Packages Projects Releases Wiki Activity

Add Boolean constraints for ArithmeticStark (#1453)

Browse Source 
* Constrain IS_READ to be boolean

* Constrain arithmetic flags to be boolean

* Comment on memory stark
This commit is contained in:
Robin Salen 2024-01-09 17:35:31 +01:00 committed by GitHub
parent 54a1313588
commit c8430dac39
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 26 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
evm/src/arithmetic/arithmetic_stark.rs
View File

@ -11,7 +11,7 @@ use plonky2::plonk::circuit_builder::CircuitBuilder;
use plonky2::util::transpose;
use static_assertions::const_assert;
use super::columns::NUM_ARITH_COLUMNS;
use super::columns::{op_flags, NUM_ARITH_COLUMNS};
use super::shift;
use crate::all_stark::Table;
use crate::arithmetic::columns::{NUM_SHARED_COLS, RANGE_COUNTER, RC_FREQUENCIES, SHARED_COLS};
@ -208,6 +208,12 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for ArithmeticSta
let lv: &[P; NUM_ARITH_COLUMNS] = vars.get_local_values().try_into().unwrap();
let nv: &[P; NUM_ARITH_COLUMNS] = vars.get_next_values().try_into().unwrap();
// Flags must be boolean.
for flag_idx in op_flags() {
let flag = lv[flag_idx];
yield_constr.constraint(flag * (flag - P::ONES));
}
// Check that `OPCODE_COL` holds 0 if the operation is not a range_check.
let opcode_constraint = (P::ONES - lv[columns::IS_RANGE_CHECK]) * lv[columns::OPCODE_COL];
yield_constr.constraint(opcode_constraint);
@ -248,6 +254,13 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for ArithmeticSta
let nv: &[ExtensionTarget<D>; NUM_ARITH_COLUMNS] =
vars.get_next_values().try_into().unwrap();
// Flags must be boolean.
for flag_idx in op_flags() {
let flag = lv[flag_idx];
let constraint = builder.mul_sub_extension(flag, flag, flag);
yield_constr.constraint(builder, constraint);
}
// Check that `OPCODE_COL` holds 0 if the operation is not a range_check.
let opcode_constraint = builder.arithmetic_extension(
F::NEG_ONE,

4
evm/src/arithmetic/columns.rs
View File

@ -43,6 +43,10 @@ pub(crate) const IS_RANGE_CHECK: usize = IS_SHR + 1;
pub(crate) const OPCODE_COL: usize = IS_RANGE_CHECK + 1;
pub(crate) const START_SHARED_COLS: usize = OPCODE_COL + 1;
pub(crate) const fn op_flags() -> Range<usize> {
IS_ADD..IS_RANGE_CHECK + 1
}
/// Within the Arithmetic Unit, there are shared columns which can be
/// used by any arithmetic circuit, depending on which one is active
/// this cycle.

8
evm/src/memory/memory_stark.rs
View File

@ -305,6 +305,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for MemoryStark<F
let filter = local_values[FILTER];
yield_constr.constraint(filter * (filter - P::ONES));
// IS_READ must be 0 or 1.
// This is implied by the MemoryStark CTL, where corresponding values are either
// hardcoded to 0/1, or boolean-constrained in their respective STARK modules.
// If this is a dummy row (filter is off), it must be a read. This means the prover can
// insert reads which never appear in the CPU trace (which are harmless), but not writes.
let is_dummy = P::ONES - filter;
@ -411,6 +415,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for MemoryStark<F
let constraint = builder.mul_sub_extension(filter, filter, filter);
yield_constr.constraint(builder, constraint);
// IS_READ must be 0 or 1.
// This is implied by the MemoryStark CTL, where corresponding values are either
// hardcoded to 0/1, or boolean-constrained in their respective STARK modules.
// If this is a dummy row (filter is off), it must be a read. This means the prover can
// insert reads which never appear in the CPU trace (which are harmless), but not writes.
let is_dummy = builder.sub_extension(one, filter);