arch/avr32/lib/csum_partial.S

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9         /*
  10          * unsigned int csum_partial(const unsigned char *buff,
  11          *                           int len, unsigned int sum)
  12          */
  13         .text
  14         .global csum_partial
  15         .type   csum_partial,"function"
  16         .align  1
  17 csum_partial:
  18         /* checksum complete words, aligned or not */
  19 3:      sub     r11, 4
  20         brlt    5f
  21 4:      ld.w    r9, r12++
  22         add     r10, r9
  23         acr     r10
  24         sub     r11, 4
  25         brge    4b
  26
  27         /* return if we had a whole number of words */
  28 5:      sub     r11, -4
  29         reteq   r10
  30
  31         /* checksum any remaining bytes at the end */
  32         mov     r9, 0
  33         mov     r8, 0
  34         cp      r11, 2
  35         brlt    6f
  36         ld.uh   r9, r12++
  37         sub     r11, 2
  38         breq    7f
  39         lsl     r9, 16
  40 6:      ld.ub   r8, r12++
  41         lsl     r8, 8
  42 7:      or      r9, r8
  43         add     r10, r9
  44         acr     r10
  45
  46         retal   r10
  47         .size   csum_partial, . - csum_partial