Compute the helper inverse of the shift high limbs

0xPolygonZero · Oct 7, 2023 · dd1a005 · dd1a005
1 parent 35cdd73
commit dd1a005
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/evm/src/witness/operation.rs b/evm/src/witness/operation.rs
@@ -497,6 +497,10 @@ fn append_shift<F: Field>(
         channel.addr_context = F::from_canonical_usize(lookup_addr.context);
         channel.addr_segment = F::from_canonical_usize(lookup_addr.segment);
         channel.addr_virtual = F::from_canonical_usize(lookup_addr.virt);
+
+        // Extra field required by the constraints for large shifts.
+        let high_limb_sum = row.mem_channels[0].value[1..].iter().copied().sum::<F>();
+        row.general.shift_mut().high_limb_sum_inv = high_limb_sum.inverse();
     }
 
     let operator = if is_shl {