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/***************************************************************************
* Copyright (C) 2010 by Spencer Oliver *
* spen@spen-soft.co.uk *
* *
* Copyright (C) 2011 Øyvind Harboe *
* oyvind.harboe@zylin.com *
* *
* Copyright (C) 2011 Clement Burin des Roziers *
* clement.burin-des-roziers@hikob.com *
* *
* Copyright (C) 2017 Armin van der Togt *
* armin@otheruse.nl *
* *
* 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
/*
Parameters
r0 - destination address
r1 - source address
r2 - half pages
r3 - bytes per half page
r4 - flash base
Variables
r0 - destination write pointer
r1 - source read pointer
r2 - source limit address
r3 - bytes per half page
r4 - flash base
r5 - pages left in current half page
r6 - temporary r/w
*/
/* offsets of registers from flash reg base */
#define STM32_FLASH_SR_OFFSET 0x18
.thumb_func
.global _start
_start:
// r2 = source + half pages * bytes per half page
muls r2, r2, r3
add r2, r1, r2
// Go to compare
b test_done
write_half_page:
// initialize pages left in current half page
mov r5, r3
write_word:
// load word from address in r1 and increase r1 by 4
ldmia r1!, {r6}
// store word to address in r0 and increase r0 by 4
stmia r0!, {r6}
// check for end of half page
subs r5, r5, #4
bne write_word
wait_busy:
// read status register into r6, loop while bottom bit is set
ldr r6, [r4, #STM32_FLASH_SR_OFFSET]
lsls r6, r6, #31
bne wait_busy
test_done:
// compare r1 and r2, loop if not equal
cmp r1, r2
bne write_half_page
// Set breakpoint to exit
bkpt #0x00
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