2917 /**

  2918  * @param crc   register containing existing CRC (32-bit)

  2919  * @param buf   register pointing to input byte buffer (byte*)

  2920  * @param len   register containing number of bytes

  2921  * @param table register that will contain address of CRC table

  2922  * @param tmp   scratch register

  2923  */

  2924 void MacroAssembler::kernel_crc32c(Register crc, Register buf, Register len,

  2925         Register table0, Register table1, Register table2, Register table3,

  2926         Register tmp, Register tmp2, Register tmp3) {

  2927   Label L_exit;

  2928   Label CRC_by64_loop, CRC_by4_loop, CRC_by1_loop;

  2929 

  2930     subs(len, len, 64);

  2931     br(Assembler::GE, CRC_by64_loop);

  2932     adds(len, len, 64-4);

  2933     br(Assembler::GE, CRC_by4_loop);

  2934     adds(len, len, 4);

  2935     br(Assembler::GT, CRC_by1_loop);

  2936     b(L_exit);

  2937 

  2938   BIND(CRC_by4_loop);

  2939     ldrw(tmp, Address(post(buf, 4)));

  2940     subs(len, len, 4);

  2941     crc32cw(crc, crc, tmp);

  2942     br(Assembler::GE, CRC_by4_loop);

  2943     adds(len, len, 4);

  2944     br(Assembler::LE, L_exit);

  2945   BIND(CRC_by1_loop);

  2946     ldrb(tmp, Address(post(buf, 1)));

  2947     subs(len, len, 1);

  2948     crc32cb(crc, crc, tmp);

  2949     br(Assembler::GT, CRC_by1_loop);

  2950     b(L_exit);

  2951 

  2952     align(CodeEntryAlignment);

  2953   BIND(CRC_by64_loop);

  2954     subs(len, len, 64);

  2955     ldp(tmp, tmp3, Address(post(buf, 16)));

  2956     crc32cx(crc, crc, tmp);

  2957     crc32cx(crc, crc, tmp3);

  2958     ldp(tmp, tmp3, Address(post(buf, 16)));

  2959     crc32cx(crc, crc, tmp);

  2960     crc32cx(crc, crc, tmp3);

  2961     ldp(tmp, tmp3, Address(post(buf, 16)));

  2962     crc32cx(crc, crc, tmp);

  2963     crc32cx(crc, crc, tmp3);

  2964     ldp(tmp, tmp3, Address(post(buf, 16)));

  2965     crc32cx(crc, crc, tmp);

  2966     crc32cx(crc, crc, tmp3);

  2967     br(Assembler::GE, CRC_by64_loop);

  2968     adds(len, len, 64-4);

  2969     br(Assembler::GE, CRC_by4_loop);

  2970     adds(len, len, 4);

  2971     br(Assembler::GT, CRC_by1_loop);

  2972   BIND(L_exit);

  2973     return;

  2974 }

  2975