// Custom registers can be read only once (also for custom register fields)

InstructionSet Zbb {
    architectural_state {
        unsigned int XLEN=32;
        const register unsigned<32> XLEN_R = 32;
        register unsigned<XLEN> X[32] [[is_main_reg]];
        register unsigned<8> LFSR;
    }
    instructions {
        TEST {
            encoding: 12'b011000000000 :: rs1[4:0] :: 3'b001 :: rd[4:0] :: 7'b0010011;
            assembly: "{name(rd)}, {name(rs1)}";
            behavior: {
                        unsigned<8> a = LFSR;
                        unsigned<8> b = LFSR;
                    }
        }
    }
}