rv_sra
emit(rv_sra(lo(rd), lo(rd), RV_REG_T0), ctx);
emit(rv_sra(lo(rd), hi(rd), RV_REG_T0), ctx);
emit(rv_sra(hi(rd), hi(rd), lo(rs)), ctx);
emit(rv_sra(lo(rd), lo(rd), lo(rs)), ctx);
emit(is64 ? rv_sra(rd, rd, rs) : rv_sraw(rd, rd, rs), ctx);