48 строки
892 B
ArmAsm
48 строки
892 B
ArmAsm
/*
|
|
* Copyright (C) 2004-2006 Atmel Corporation
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
/*
|
|
* unsigned int csum_partial(const unsigned char *buff,
|
|
* int len, unsigned int sum)
|
|
*/
|
|
.text
|
|
.global csum_partial
|
|
.type csum_partial,"function"
|
|
.align 1
|
|
csum_partial:
|
|
/* checksum complete words, aligned or not */
|
|
3: sub r11, 4
|
|
brlt 5f
|
|
4: ld.w r9, r12++
|
|
add r10, r9
|
|
acr r10
|
|
sub r11, 4
|
|
brge 4b
|
|
|
|
/* return if we had a whole number of words */
|
|
5: sub r11, -4
|
|
reteq r10
|
|
|
|
/* checksum any remaining bytes at the end */
|
|
mov r9, 0
|
|
mov r8, 0
|
|
cp r11, 2
|
|
brlt 6f
|
|
ld.uh r9, r12++
|
|
sub r11, 2
|
|
breq 7f
|
|
lsl r9, 16
|
|
6: ld.ub r8, r12++
|
|
lsl r8, 8
|
|
7: or r9, r8
|
|
add r10, r9
|
|
acr r10
|
|
|
|
retal r10
|
|
.size csum_partial, . - csum_partial
|