want to check update

AztecProtocol · Sep 18, 2024 · 3facaab · 3facaab
1 parent bb1e0e2
commit 3facaab
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/barretenberg/cpp/src/barretenberg/stdlib/hash/sha256/sha256_plookup.cpp b/barretenberg/cpp/src/barretenberg/stdlib/hash/sha256/sha256_plookup.cpp
@@ -140,11 +140,11 @@ std::array<field_t<Builder>, 64> extend_witness(const std::array<field_t<Builder
             w_out = witness_t<Builder>(
                 ctx, fr(w_out_raw.get_value().from_montgomery_form().data[0] & (uint64_t)0xffffffffULL));
         }
-        field_pt divisor = w_out_raw / w_out;
+        constexpr fr inv_pow_two = fr(2).pow(32).invert();
+        field_pt w_out_raw_inv_pow_two = w_out_raw * inv_pow_two;
+        field_pt w_out_inv_pow_two = w_out * inv_pow_two;
+        field_pt divisor = (w_out_raw_inv_pow_two - w_out_inv_pow_two).normalize();
         ctx->create_new_range_constraint(divisor.witness_index, 3);
-        fr power_two = fr(1).pow(32);
-        ctx->create_add_gate(
-            { divisor.witness_index, w_out.witness_index, w_out_raw.witness_index, power_two, fr(1), fr(-1), fr(0) });
         w_sparse[i] = sparse_witness_limbs(w_out);
     }