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@---------------------------------------------------------------------------------
.section ".init"
.global _start
.global _init
@---------------------------------------------------------------------------------
.align 4
.arm
@---------------------------------------------------------------------------------
_start:
@---------------------------------------------------------------------------------
mov r0, #0x04000000 @ IME = 0;
str r0, [r0, #0x208]
mov r0, #0x12 @ Switch to IRQ Mode
msr cpsr, r0
ldr sp, =__sp_irq @ Set IRQ stack
mov r0, #0x13 @ Switch to SVC Mode
msr cpsr, r0
ldr sp, =__sp_svc @ Set SVC stack
mov r0, #0x1F @ Switch to System Mode
msr cpsr, r0
ldr sp, =__sp_usr @ Set user stack
ldr r0, =__bss_start @ Clear BSS section to 0x00
ldr r1, =__bss_end
sub r1, r1, r0
bl ClearMem
ldr r3, =__libc_init_array @ global constructors
bl _call_via_r3
mov r0, #0 @ int argc
mov r1, #0 @ char *argv[]
ldr r3, =main
bl _call_via_r3 @ jump to user code
@ If the user ever returns, return to flash cartridge
mov r0, #0x08000000
bx r0
@---------------------------------------------------------------------------------
@ Clear memory to 0x00 if length != 0
@ r0 = Start Address
@ r1 = Length
@---------------------------------------------------------------------------------
ClearMem:
@---------------------------------------------------------------------------------
mov r2, #3 @ Round down to nearest word boundary
add r1, r1, r2 @ Shouldn't be needed
bics r1, r1, r2 @ Clear 2 LSB (and set Z)
bxeq lr @ Quit if copy size is 0
mov r2, #0
ClrLoop:
stmia r0!, {r2}
subs r1, r1, #4
bne ClrLoop
bx lr
@---------------------------------------------------------------------------------
@ Copy memory if length != 0
@ r1 = Source Address
@ r2 = Dest Address
@ r4 = Dest Address + Length
@---------------------------------------------------------------------------------
CopyMemCheck:
@---------------------------------------------------------------------------------
sub r3, r4, r2 @ Is there any data to copy?
@---------------------------------------------------------------------------------
@ Copy memory
@ r1 = Source Address
@ r2 = Dest Address
@ r3 = Length
@---------------------------------------------------------------------------------
CopyMem:
@---------------------------------------------------------------------------------
mov r0, #3 @ These commands are used in cases where
add r3, r3, r0 @ the length is not a multiple of 4,
bics r3, r3, r0 @ even though it should be.
bxeq lr @ Length is zero, so exit
CIDLoop:
ldmia r1!, {r0}
stmia r2!, {r0}
subs r3, r3, #4
bne CIDLoop
bx lr
_init:
bx lr
@---------------------------------------------------------------------------------
.align
@ .pool
@ .end
@---------------------------------------------------------------------------------
@---------------------------------------------------------------------------------
.section ".fini"
.global _fini
@---------------------------------------------------------------------------------
.align 4
.arm
@---------------------------------------------------------------------------------
_fini:
bx lr
@---------------------------------------------------------------------------------
.align
.pool
.end
@---------------------------------------------------------------------------------
|
