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/*
* flash_button.s
*
* Copyright © 2018 Thomas White <taw@bitwiz.org.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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
.include "swi_numbers.h"
.global flash_button
flash_button:
MOV R0, #0 @ Get GPLEV0
SWI OS_GetGPIO
TST R0, #1<<17 @ Check GPIO 17
BLNE flash_leds
B flash_button
flash_leds:
STMDB R13!, {LR}
MOV R2, #5 @ Number of times to flash
1:
MOV R0, #0 @ Flash first set of GPIOs
MOV R1, #1<<16
SWI OS_ClearGPIO
MOV R1, #1<<18
SWI OS_SetGPIO
BL pause
MOV R1, #1<<18
SWI OS_ClearGPIO
MOV R1, #1<<16
SWI OS_SetGPIO
BL pause
SUBS R2, R2, #1
BNE 1b
MOV R1, #1<<18
ORR R1, #1<<16
SWI OS_ClearGPIO
LDMIA R13!, {PC}
pause:
MOV R1, #0x3f000
1:
SUBS R1, R1, #1
BNE 1b
MOV PC, LR
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