gba/crt0.s
2018-11-07 21:21:17 -07:00

35 lines
724 B
ArmAsm

.arm
__start:
b .Linit
@ ROM header will be filled in by gbafix
.fill 188, 1, 0
.Linit:
@ set IRQ stack pointer
mov r0, #0x12
msr CPSR_cf, r0
ldr sp, =0x3007fa0
@ set user stack pointer
mov r0, #0x1f
msr CPSR_cf, r0
ldr sp, =0x3007f00
@ copy .data section to IWRAM
ldr r0, =__data_lma @ source address
ldr r1, =__data_start @ destination address
ldr r3, =__data_end
sub r2, r3, r1
beq .Lskip @ don't try to copy an empty .data section
add r2, #3
mov r2, r2, asr #2 @ length (in words)
add r2, #0x04000000 @ copy by words
swi 0xb0000
.Lskip:
@ jump to user code
ldr r0, =main
bx r0
.pool