help: AR NDS is possible mutiply on ar code?

[TheAleG]

exist a AR Adress that multiply the value stored with
DA000000 XXXXXXXX function?
?

like DA000000 01234567 (and the value is 400)
then 400 * 100 = 40000
and save the value back
like D7000000 01234567
??

[Demonic722]

No; you would have to use ASM to multiply.

[TheAleG]

and where i find the material to learn NDS ASM?

[Demonic722]

Honestly, I've never came across a good tutorial for ARM ASM; however, a friend of mine named Siestacat and I wrote a beginners ASM tutorial for NDS located here. We haven't really updated that tutorial in awhile so if there are grammar errors or anything, please let me know so I can fix them.

Also, you should look into studying the ARM Instruction Set.

[TheAleG]

i have a 2 questions,
the ds asm is
instruction destination,source
or
instruction source,destination

and the use o [] (what they realy do)

[Demonic722]

i have a 2 questions,
the ds asm is
instruction destination,source
or
instruction source,destination

Example:

add     r0,r2,r1          ;@r0 = r2 + r1

and the use o [] (what they realy do)

I always looked at the brackets as "into."

Example:

ldr     r0,[r2,r1]        ;@load  r0 into r2 + r1
str     r0,[r2,r3]        ;@store r0 into r2 + r3

[TheAleG]

for learn i will use a rune factory 3 code

ldr r0,BagSlot1
ldrh r1,ItemGold
strh r1,[r0]
bx lr

BagSlot1:
.long 0x023139BC
ItemGold:
.short 0x06DE

so its load on r0 the adress of bag slot 1
load on r1 the value of gold ore + 1unit (2DE + 400) 2de is the "item id" and 400 is has 1 of it (so item id+400=1 item id+800=2 etc... ) (in hex)
store the value in r1 into r0
end code

define

so this code is ok? it will add the value defined in r1 on r0?

[TheAleG]

when i run the code on no$gba
i get 2 error on no$gba

unknown command on line 9
unexpected end of file

i did something wrong?

[Demonic722]

for learn i will use a rune factory 3 code


so this code is ok? it will add the value defined in r1 on r0?

Yes; in other words, that code looks like this:

123139BC 000006DE

when i run the code on no$gba
i get 2 error on no$gba

unknown command on line 9
unexpected end of file

i did something wrong?

How are you compiling the ASM?

The Code should compile to:

023FE074 012FFF11
E0000000 00000016
E59F0008 E1DF10B8
E1C010B0 E12FFF1E
023139BC 000006DE
023FE074 E3520003

I don't think NO$GBA supports Kenobi's ARDS Hack #4 so you will have to either patch the ROM with the code, use your flash cart, or ARDS and retail cart if you have it.

[TheAleG]

the no$gba was a option to load asm
so i used it

[TheAleG]

well the code work
but

i'm making a code that change the "upgraded item"
since you update 9times

but
1 need
4 upgrade store address
9 inventory address
2 multiply address
1 subtract address

and the code become tooooooooooooooo long in r1 to r40
there a way to reuse the "r"

like i want in this code:

ldr r0,BagSlot1E1
ldr r1,BagSlot4
ldr r2,Mul1
mov r3,#0
str r1,[r3]
sub r3,r2
str r3,[r0]
ldr r1,BagSlot5
str r1,[r3]
sub r3,r2
mul r4,r3,r2
str r4,[r0]
ldr r1,BagSlot5
ldr r2,Mul2
str r1,[r3]
sub r3,r2
mul r4,r3,r2
str r4,[r0]
bx lr

[Helder]

Some of those lines there like the sub r3,r2 don't even need to be there since you are making r3 have #0 then its doing nothing but taking up space in your code and all you need to do is look up push and pop instructions. Basically you push the registers into the stack which is temporary holding area then once you need those registers back with the values you originally pushed to stack then you pop them back. Look some info on those 2 instructions and also look at your code more closely.

[Demonic722]

There's no such thing as an "r40" in ARM9 ASM. What is the code supposed to do? I need a more thorough explanation than "i'm making a code that change the 'upgraded item' since you update 9 times" if you need further assistance.

[TheAleG]

since i don't know if the r3 was been used by the game i clean it first
the game store the id of item used on upgrade in 3 addresses
then if i put a item on a slot i will store on that address
if i try to use a code to store 1 value, it's ok but, if i try 2 or 3 i can't store since there a limit of "r#"
so there a way of change the address hold on r0 for exemple?

[Demonic722]

I still don't understand what you're trying to do. Is English your first language? Anyway, you can reuse registers once you're done using them.

Example:

ldr     r0,address_one
mov     r1,#0xFF
strb    r1,[r0]
ldr     r0,address_two
mov     r1,#0x0
strb    r1,[r0]
bx      lr

address_one:
.long 0x02000000
address_two:
.long 0x021C0000