73 lines
2.2 KiB
ArmAsm
73 lines
2.2 KiB
ArmAsm
/***************************************************************************
|
|
* 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. *
|
|
***************************************************************************/
|
|
|
|
.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
|