logic_constraint.cpp

Go to the documentation of this file.

// === AUDIT STATUS ===
// internal:    { status: Complete, auditors: [Suyash], commit: e4712cda8def49d75fbba2d361625fc5e21945f5 }
// external_1:  { status: not started, auditors: [], commit: }
// external_2:  { status: not started, auditors: [], commit: }
// =====================
 
#include "logic_constraint.hpp"
#include "barretenberg/stdlib/primitives/logic/logic.hpp"
 
namespace acir_format {
 
template <typename Builder>
void create_logic_gate(Builder& builder,
                       const WitnessOrConstant<bb::fr> a,
                       const WitnessOrConstant<bb::fr> b,
                       const uint32_t result,
                       const size_t num_bits,
                       const bool is_xor_gate)
{
    using field_ct = bb::stdlib::field_t<Builder>;
 
    field_ct left = to_field_ct(a, builder);
    field_ct right = to_field_ct(b, builder);
 
    field_ct computed_result = bb::stdlib::logic<Builder>::create_logic_constraint(left, right, num_bits, is_xor_gate);
 
    // In write-VK mode the result witness holds a dummy zero. In certain cases, the computed result is non-zero so the
    // assert_equal would spuriously fail. Patch the witness value so the downstream assertion sees the correct value.
    // Eg. for an XOR gate, if the inputs are constants such that the result is a non-zero constant, the assert_equal
    // will fail in write-VK mode since the result witness is initialized to zero.
    if (builder.is_write_vk_mode()) {
        builder.set_variable(result, computed_result.get_value());
    }
 
    field_ct acir_result = field_ct::from_witness_index(&builder, result);
    computed_result.assert_equal(acir_result);
}
 
template void create_logic_gate<bb::MegaCircuitBuilder>(bb::MegaCircuitBuilder& builder,
                                                        const WitnessOrConstant<bb::fr> a,
                                                        const WitnessOrConstant<bb::fr> b,
                                                        const uint32_t result,
                                                        const size_t num_bits,
                                                        const bool is_xor_gate);
template void create_logic_gate<bb::UltraCircuitBuilder>(bb::UltraCircuitBuilder& builder,
                                                         const WitnessOrConstant<bb::fr> a,
                                                         const WitnessOrConstant<bb::fr> b,
                                                         const uint32_t result,
                                                         const size_t num_bits,
                                                         const bool is_xor_gate);
 
} // namespace acir_format