| Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 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 |