.code 32
startup:
- ldr sp, =_stacktop
+ @ stop all but one of the cores
+ mrc p15, 0, r0, c0, c0, 5
+ ands r0, r0, #0xff
+ bne exit
- mov r0, #2
- bl dbgled
+ @ setup stack
+ ldr sp, =_stacktop
@ clear bss
ldr r0, =_bss_start
subs r1, #4
bne 0b
1:
- bl main
-
- mov r0, #0
- bl dbgled
+ blx main
.global exit
exit: wfe
b exit
- .global dbgled
-dbgled:
- ldr r3, =0x3f200000 @ gpio base
- ldr r2, =0x9000 @ gpio 24 and 25 -> output
- str r2, [r3, #8] @ store to GPFSEL2
- ldr r2, =0x01000000 @ bit 24
- tst r0, #1
- strne r2, [r3, #0x1c] @ GPSET0
- streq r2, [r3, #0x28] @ GPCLR0
- lsl r2, #1
- tst r0, #2
- strne r2, [r3, #0x1c] @ GPSET0
- streq r2, [r3, #0x28] @ GPCLR0
- bx lr
-
-
@ vi:set filetype=armasm: