buildscripts/dkarm/crtls/er_crt0.s

57 lines
1022 B
ArmAsm

@---------------------------------------------------------------------------------
@ nintendo e-reader startup code
@---------------------------------------------------------------------------------
@ author : tim schuerewegen
@ version : 1.0
@---------------------------------------------------------------------------------
.section ".init"
.global _start
.align
.arm
@---------------------------------------------------------------------------------
_start:
@---------------------------------------------------------------------------------
b start_vector
.long 0
.long 0x02000000
start_vector:
@ enter thumb mode
adr r0, _start_thumb + 1
bx r0
.thumb
_start_thumb:
@ save return address (rom)
mov r3, lr
@ clear bss section
ldr r0, =__bss_start
ldr r1, =__bss_end
mov r2, #0
_loop_bss_clear:
strb r2, [r0]
add r0, #1
cmp r0, r1
blt _loop_bss_clear
@ set return address (rom)
mov lr, r3
@ jump to main
ldr r3, =main
bx r3
.align
.pool
.end
.align
.pool
.end