memory_masking_gadget.hpp

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#ifndef MEMORY_MASKING_GADGET_HPP_
#define MEMORY_MASKING_GADGET_HPP_
 
#include <libsnark/gadgetlib1/gadgets/cpu_checkers/tinyram/components/tinyram_protoboard.hpp>
#include <libsnark/gadgetlib1/gadgets/cpu_checkers/tinyram/components/word_variable_gadget.hpp>
 
namespace libsnark
{
 
template<typename FieldT>
class memory_masking_gadget : public tinyram_standard_gadget<FieldT>
{
private:
    pb_linear_combination<FieldT> shift;
    pb_variable<FieldT> is_word0;
    pb_variable<FieldT> is_word1;
    pb_variable_array<FieldT> is_subaddress;
    pb_variable_array<FieldT> is_byte;
 
    pb_linear_combination<FieldT> masked_out_word0;
    pb_linear_combination<FieldT> masked_out_word1;
    pb_linear_combination_array<FieldT> masked_out_bytes;
 
    std::shared_ptr<inner_product_gadget<FieldT>>
        get_masked_out_dw_contents_prev;
 
    pb_variable<FieldT> masked_out_dw_contents_prev;
    pb_variable<FieldT> expected_dw_contents_next;
 
public:
    doubleword_variable_gadget<FieldT> dw_contents_prev;
    dual_variable_gadget<FieldT> subaddress;
    pb_linear_combination<FieldT> subcontents;
    pb_linear_combination<FieldT> access_is_word;
    pb_linear_combination<FieldT> access_is_byte;
    doubleword_variable_gadget<FieldT> dw_contents_next;
 
    memory_masking_gadget(
        tinyram_protoboard<FieldT> &pb,
        const doubleword_variable_gadget<FieldT> &dw_contents_prev,
        const dual_variable_gadget<FieldT> &subaddress,
        const pb_linear_combination<FieldT> &subcontents,
        const pb_linear_combination<FieldT> &access_is_word,
        const pb_linear_combination<FieldT> &access_is_byte,
        const doubleword_variable_gadget<FieldT> &dw_contents_next,
        const std::string &annotation_prefix = "");
    void generate_r1cs_constraints();
    void generate_r1cs_witness();
};
 
} // namespace libsnark
 
#include <libsnark/gadgetlib1/gadgets/cpu_checkers/tinyram/components/memory_masking_gadget.tcc>
 
#endif // MEMORY_MASKING_GADGET_HPP_