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/***************************************************************************
* Copyright (C) 2011 by Andreas Fritiofson *
* andreas.fritiofson@gmail.com *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
***************************************************************************/
.text
.syntax unified
.cpu cortex-m0
.thumb
/* Params:
* r0 - flash base (in), status (out)
* r1 - count (halfword-16bit)
* r2 - workarea start
* r3 - workarea end
* r4 - target address
* Clobbered:
* r5 - rp
* r6 - wp, tmp
* r7 - tmp
*/
#define STM32_FLASH_SR_OFFSET 0x0c /* offset of SR register from flash reg base */
.thumb_func
.global _start
_start:
wait_fifo:
ldr r6, [r2, #0] /* read wp */
cmp r6, #0 /* abort if wp == 0 */
beq exit
ldr r5, [r2, #4] /* read rp */
cmp r5, r6 /* wait until rp != wp */
beq wait_fifo
ldrh r6, [r5] /* "*target_address++ = *rp++" */
strh r6, [r4]
adds r5, #2
adds r4, #2
busy:
ldr r6, [r0, #STM32_FLASH_SR_OFFSET] /* wait until BSY flag is reset */
movs r7, #1
tst r6, r7
bne busy
movs r7, #0x14 /* check the error bits */
tst r6, r7
bne error
cmp r5, r3 /* wrap rp at end of buffer */
bcc no_wrap
mov r5, r2
adds r5, #8
no_wrap:
str r5, [r2, #4] /* store rp */
subs r1, r1, #1 /* decrement halfword count */
cmp r1, #0
beq exit /* loop if not done */
b wait_fifo
error:
movs r0, #0
str r0, [r2, #4] /* set rp = 0 on error */
exit:
mov r0, r6 /* return status in r0 */
bkpt #0
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