67 lines
2.0 KiB
ArmAsm
67 lines
2.0 KiB
ArmAsm
/***************************************************************************
|
|
* Copyright (C) 2010 by Spencer Oliver *
|
|
* spen@spen-soft.co.uk *
|
|
* *
|
|
* This program is free software; you can redistribute it and/or modify *
|
|
* it under the terms of the GNU General Public License as published by *
|
|
* the Free Software Foundation; either version 2 of the License, or *
|
|
* (at your option) any later version. *
|
|
* *
|
|
* This program is distributed in the hope that it will be useful, *
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
|
|
* GNU General Public License for more details. *
|
|
* *
|
|
* You should have received a copy of the GNU General Public License *
|
|
* along with this program; if not, write to the *
|
|
* Free Software Foundation, Inc., *
|
|
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
|
|
***************************************************************************/
|
|
|
|
/*
|
|
parameters:
|
|
r0 - address in - crc out
|
|
r1 - char count
|
|
*/
|
|
|
|
.text
|
|
.syntax unified
|
|
.arch armv7-m
|
|
.thumb
|
|
.thumb_func
|
|
|
|
.align 2
|
|
|
|
_start:
|
|
main:
|
|
mov r2, r0
|
|
mov r0, #0xffffffff /* crc */
|
|
mov r3, r1
|
|
mov r4, #0
|
|
b ncomp
|
|
nbyte:
|
|
ldrb r1, [r2, r4]
|
|
|
|
ldr r7, CRC32XOR
|
|
eor r0, r0, r1, asl #24
|
|
mov r5, #0
|
|
loop:
|
|
cmp r0, #0
|
|
mov r6, r0, asl #1
|
|
add r5, r5, #1
|
|
mov r0, r6
|
|
it lt
|
|
eorlt r0, r6, r7
|
|
cmp r5, #8
|
|
bne loop
|
|
|
|
add r4, r4, #1
|
|
ncomp:
|
|
cmp r4, r3
|
|
bne nbyte
|
|
bkpt #0
|
|
|
|
CRC32XOR: .word 0x04c11db7
|
|
|
|
.end
|