[ASM & Hex] Accessing script banks in ASM

Working on an ASM routine, and need to write that value of a register to a script bank. (Specifically, script bank 0). A buffer will not work in this case as it is a pointer and not text. The only alternative I think is possible would be to directly write the value of the register to the ROM to a specific pointer, but I don't think ASM can do that.

What are the memory offsets for the script banks? Alternatively, how does one write 4 bytes of data to the rom?

Edit: Script bank 0 is located at 0x03000F14. How do I write to this offset in ASM?

hjk321 said:

Working on an ASM routine, and need to write that value of a register to a script bank. (Specifically, script bank 0). A buffer will not work in this case as it is a pointer and not text. The only alternative I think is possible would be to directly write the value of the register to the ROM to a specific pointer, but I don't think ASM can do that.

What are the memory offsets for the script banks? Alternatively, how does one write 4 bytes of data to the rom?

Edit: Script bank 0 is located at 0x03000F14. How do I write to this offset in ASM?

Click to expand...

You need to use str command to write to the address. Also, you cannot modify the ROM during runtime (look up what ROM stands for). I think something like this would work:
ldr r0, =(0x03000F14)
ldr r1, =(address of script)
str r1, [r0]

I might have the str registers backwards, it's been some time and I'm too lazy to double check :)

FBI said:

You need to use str command to write to the address. Also, you cannot modify the ROM during runtime (look up what ROM stands for). I think something like this would work:
ldr r0, =(0x03000F14)
ldr r1, =(address of script)
str r1, [r0]

I might have the str registers backwards, it's been some time and I'm too lazy to double check :)

Click to expand...

Wow, didn't expect to have to original author of the tutorial I used to actually respond...

Anyways, I have what I believe to be correct ASM, but it won't compile, with errors at line 9 (see below). For some reason, removing line 14 will allow the code to compile correctly. I've commented my code to the best of my understanding, using your script for navigating tables as a base. I would really appreciate it if you could tell me why it isn't compiling.

The main purpose of the routine is to read a table of pointers to text based on the value of a variable, and write it to script bank 0 for use with the preparemsg command in XSE. The table is extremely simple, with 4 bytes per entry and no terminator byte or failsafe (the specific use case eliminates the need for a failsafe). Yeah, I probably coulda made a conditional script but the variable will have hundreds, maybe a thousand possible values, and I don't know what they all are right now. That makes for spaghetti code from Hades...


There are 2 errors at line 9. Keep in mind that removing line 14 will magically make these errors go away for some reason, although I sincerely doubt said code would work.
Here is the output:


Thank you for any insight you could provide on this matter. I would also like to thank you for being the only hacking "giant" still active. (Well... diego is still around here somewhere.) I use your routines regularly, and I found your storage system especially useful. <3

Edit: On a whim I decided to put an .align 2 before the var definition because that's what the error was saying. It compiled, and I can confirm it works in-game. So apparently I'm supposed to put .align 2 before every label definition? Could you please explain why that worked? What the heck does .align 2 actually do?