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   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2010 by Spencer Oliver                                  *
   5  *   spen@spen-soft.co.uk                                                  *
   6  ***************************************************************************/
   7
   8 /*
   9         r0 - address in - crc out
  10         r1 - char count
  11 */
  12
  13         .text
  14         .arm
  15
  16 _start:
  17 main:
  18         mov             r2, r0
  19         mov             r0, #0xffffffff /* crc */
  20         mov             r3, r1
  21         mov             r4, #0
  22         b               ncomp
  23 nbyte:
  24         ldrb    r1, [r2, r4]
  25         ldr             r7, CRC32XOR
  26         eor             r0, r0, r1, asl #24
  27         mov             r5, #0
  28 loop:
  29         cmp             r0, #0
  30         mov             r6, r0, asl #1
  31         add             r5, r5, #1
  32         mov             r0, r6
  33         eorlt   r0, r6, r7
  34         cmp             r5, #8
  35         bne             loop
  36         add             r4, r4, #1
  37 ncomp:
  38         cmp             r4, r3
  39         bne             nbyte
  40 end:
  41         bkpt    #0
  42
  43 CRC32XOR:       .word   0x04c11db7
  44
  45         .end