[ASM & Hex✓] Help with this ASM routine for evolution based on a flag.

[Dr. Seuss]

I've been trying to insert an evolution method based on a flag. So basically if a flag is set, then Pokémon evolves. The issue I´m facing is that if the flag is nto set, everything continues, if the flag is set, rom crashes.

Here is the ASM code I wrote:

.text
.align 2
.thumb
.thumb_func
.global setflagevo

main:
	push {r0-r7}
	add r0, r6, r7
	lsl r0, r0, #0x3
	add r0, r2, r0
	add r3, r0, r3
	ldrh r2, [r3, #0x2]
	mov r0, r8
	mov r5, #0x0
	ldr r0, flag_number
	ldr r2, flag_routine
	ldrh r2, [r2, #0x0]
	bl linker
	cmp r0, #0x1	
	bne flagnotset
	mov r10, r3
	pop {r0-r7}
	mov r1, r10
	ldr r0, levelcheckloc
	bx r0

linker:
	bx r2

flagnotset:
	pop {r0-r7}
	ldr r0, noevo
	bx r0

.align
flag_number: .word 0x00000(Flag Number)
flag_routine: .word 0x0806E6D0 +1
levelcheckloc: .word 0x08043017
noevo: .word 0x08043111

Why does my routine isn't working as intended?

 

[kleenexfeu]

I've been trying to insert an evolution method based on a flag. So basically if a flag is set, then Pokémon evolves. The issue I´m facing is that if the flag is nto set, everything continues, if the flag is set, rom crashes.

Here is the ASM code I wrote:

.text
.align 2
.thumb
.thumb_func
.global setflagevo

main:
	push {r0-r7}
	add r0, r6, r7
	lsl r0, r0, #0x3
	add r0, r2, r0
	add r3, r0, r3
	ldrh r2, [r3, #0x2]
	mov r0, r8
	mov r5, #0x0
	ldr r0, flag_number
	ldr r2, flag_routine
	ldrh r2, [r2, #0x0]
	bl linker
	cmp r0, #0x1	
	bne flagnotset
	mov r10, r3
	pop {r0-r7}
	mov r1, r10
	ldr r0, levelcheckloc
	bx r0

linker:
	bx r2

flagnotset:
	pop {r0-r7}
	ldr r0, noevo
	bx r0

.align
flag_number: .word 0x00000(Flag Number)
flag_routine: .word 0x0806E6D0 +1
levelcheckloc: .word 0x08043017
noevo: .word 0x08043111

Why does my routine isn't working as intended?

This routine looks completely broken to me, I'm surprised it doesn't crash all the time. Maybe try this :

.text
.align 2
.thumb
.thumb_func
.global setflagevo

main:
	push {r0-r7}
	add r0, r6, r7
	lsl r0, r0, #0x3
	add r0, r2, r0
	add r3, r0, r3
	ldrh r2, [r3, #0x2]
	mov r0, r8 @ THIS is actually useless, r0 is overwritten 2 instruction after
	mov r5, #0x0
	ldr r0, flag_number
	ldr r2, flag_routine
       @  ldrh r2, [r2, #0x0] @ really bad, you're basically calling a function that is supposed to be at an address in the bios, and that's the reason I'm surprised it doesn't crash just all the time
	bl linker
	cmp r0, #0x1	
	bne flagnotset
	mov r10, r3 @ I hope the person who did the routine checked r10 was safe to use here
	pop {r0-r7}
	mov r1, r10
	ldr r0, levelcheckloc
	bx r0

linker:
	bx r2

flagnotset:
	pop {r0-r7}
	ldr r0, noevo
	bx r0

.align
flag_number: .word 0x00000(Flag Number)
flag_routine: .word 0x0806E6D0 +1
levelcheckloc: .word 0x08043017
noevo: .word 0x08043111

 

[Dr. Seuss]

This routine looks completely broken to me, I'm surprised it doesn't crash all the time. Maybe try this :

.text
.align 2
.thumb
.thumb_func
.global setflagevo

main:
	push {r0-r7}
	add r0, r6, r7
	lsl r0, r0, #0x3
	add r0, r2, r0
	add r3, r0, r3
	ldrh r2, [r3, #0x2]
	mov r0, r8 @ THIS is actually useless, r0 is overwritten 2 instruction after
	mov r5, #0x0
	ldr r0, flag_number
	ldr r2, flag_routine
       @  ldrh r2, [r2, #0x0] @ really bad, you're basically calling a function that is supposed to be at an address in the bios, and that's the reason I'm surprised it doesn't crash just all the time
	bl linker
	cmp r0, #0x1	
	bne flagnotset
	mov r10, r3 @ I hope the person who did the routine checked r10 was safe to use here
	pop {r0-r7}
	mov r1, r10
	ldr r0, levelcheckloc
	bx r0

linker:
	bx r2

flagnotset:
	pop {r0-r7}
	ldr r0, noevo
	bx r0

.align
flag_number: .word 0x00000(Flag Number)
flag_routine: .word 0x0806E6D0 +1
levelcheckloc: .word 0x08043017
noevo: .word 0x08043111

Duuuuude. I tested it and it works perfectly. I'm a total ASMnoob so I realize now why it didn't work.

Thanks a lot. My question has been resolved.