LXR linux/arch/avr32/lib/csum

   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
  17csum_partial:
  18        /* checksum complete words, aligned or not */
  193:      sub     r11, 4
  20        brlt    5f
  214:      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 */
  285:      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
  406:      ld.ub   r8, r12++
  41        lsl     r8, 8
  427:      or      r9, r8
  43        add     r10, r9
  44        acr     r10
  45
  46        retal   r10
  47        .size   csum_partial, . - csum_partial
  48