[ASM & Hex] Current HP Check

[Lance Koijer 2.0]

Hello guys..

I am trying to code an ASM that checks if the current HP is lower or equal to the Half of the 1st Party Pokémon's Total HP.

I have thought how to get the half in an ASM but the problem I have encountered is the byte indicator is not writing in the loaded address..

here's the code:

.text
.align 2
.thumb
.thumb_func


main:
	push {r0-r3, lr}
	ldr r0, =(0x20242Dc) @loads the Total HP
	ldrb r0, [r0]
	ldr r1, =(0x20242Da) @loads the current hp
	ldrb r1, [r1]
	mov r2, #0x5 @multiplies to 5 to get the half 
	mul r0, r2, r0 @gets the half of Total HP
	mov r3, #0xA @moves one decimal to current HP
	mul r1, r3, r1 @gets the value of Current HP
	cmp r1, r0 @compares if Current HP is higher than Half of the total HP
	bhi push2
	ldr r1, =(0x203c1b4) @freespace
	mov r0, #0x1
	strb r1, [r0]	 @stores byte 1 to indicate that the Current HP is lower than or equal the half of total HP
	pop {r0-r3, pc}	


push2:
	ldr r1, =(0x203c1b4)
	mov r0, #0x0
	strb r1, [r0] @stores byte 0 to indicate that the Current HP is higher than the half of total HP
	pop {r0-r3, pc}

it feels to me that it's either the storing of the byte or the branch checking makes the code not functioning. If someone can help me fix this, it is much appreciated. Thanks.

 

[Koople]

Hello guys..

I am trying to code an ASM that checks if the current HP is lower or equal to the Half of the 1st Party Pokémon's Total HP.

I have thought how to get the half in an ASM but the problem I have encountered is the byte indicator is not writing in the loaded address..

here's the code:

.text
.align 2
.thumb
.thumb_func


main:
	push {r0-r3, lr}
	ldr r0, =(0x20242Dc) @loads the Total HP
	ldrb r0, [r0]
	ldr r1, =(0x20242Da) @loads the current hp
	ldrb r1, [r1]
	mov r2, #0x5 @multiplies to 5 to get the half 
	mul r0, r2, r0 @gets the half of Total HP
	mov r3, #0xA @moves one decimal to current HP
	mul r1, r3, r1 @gets the value of Current HP
	cmp r1, r0 @compares if Current HP is higher than Half of the total HP
	bhi push2
	ldr r1, =(0x203c1b4) @freespace
	mov r0, #0x1
	strb r1, [r0]	 @stores byte 1 to indicate that the Current HP is lower than or equal the half of total HP
	pop {r0-r3, pc}	


push2:
	ldr r1, =(0x203c1b4)
	mov r0, #0x0
	strb r1, [r0] @stores byte 0 to indicate that the Current HP is higher than the half of total HP
	pop {r0-r3, pc}

it feels to me that it's either the storing of the byte or the branch checking makes the code not functioning. If someone can help me fix this, it is much appreciated. Thanks.

A couple notes:
- The current/total HP are halfwords (2 bytes), so you should be using ldrh
- you should use a right shift to divide by 2 (lsr rX, rX, #0x1)
- you're storing r1 into r0. So you are storing the address into address 0x0 or 0x1. You should do strb r0, [r1] to store the value of r0 into the address of r1
- EDIT: and rather than using some free ram, you might want to store into a temporary variable such as the lastresult variable at 0x020370d0

Hope this helps :)

 

[Lance Koijer 2.0]

A couple notes:
- The current/total HP are halfwords (2 bytes), so you should be using ldrh
- you should use a right shift to divide by 2 (lsr rX, rX, #0x1)
- you're storing r1 into r0. So you are storing the address into address 0x0 or 0x1. You should do strb r0, [r1] to store the value of r0 into the address of r1
- EDIT: and rather than using some free ram, you might want to store into a temporary variable such as the lastresult variable at 0x020370d0

Hope this helps :)

Thanks for the response. Very.

I'll gonna try that.

 

[Blah]

Well, that's the most complicated solution to checking if a number is double. I'd optimize that portion of it, and also generalize this into an easy to call function.

push {lr}
mov r3, #100
mul r3, r3, r0
ldr r0, totalhp
add r0, r0, r3
ldrh r1, [r0, #2]
ldrh r0, [r0]

do calc

This would require a small wrapper to call it from a script properly, but it'd be worth it to get rid of the hard coded portions.

 

[Lance Koijer 2.0]

Well, that?s the most complicated solution to checking if a number is double. I?d optimize that portion of it, and also generalize this into an easy to call function.



This would require a small wrapper to call it from a script properly, but it?d be worth it to get rid of the hard coded portions.

Sweet. Thanks for this.