[PPC ASM] How do I render Text?

[CosmoCortney]

Hello,
I've been working on a PPC-based code handler for Wii U cheats and thought it'd be nice to have a code type to render text. So we can load a value from memory and display it on screen.
But I don't know how to express a sort of console::write_line instruction in PPC.

But as you can see here, it is possible: https://www.youtube.com/watch?v=N0DL1HniY0g

[Pyriel]

Judging by what I can see in the brief moments he has his source code up, what he's doing is patching a Wind Waker ROM directly, which may mean he's hijacking one of its routines to handle that text display. The only other simple, small-footprint option would be if the kernel or *visor or whatever provides text-printing routines that can break through a game like that, and you can find where they're located reliably to jump into them. Barring that, you'd have to use library code, and OSScreenPutFontEx appears to be your boy there. Although, it looks like a more than negligible amount of initialization is required to use it, and it unless you can link it into whatever you're building, it wouldn't suit your requirement of expressing WriteLine in PPC.

[CosmoCortney]

well, a friend and I have been testing a few things like compiling a hello world and loaded it into RAM, while the game was running we jumped our execution into there but it obviously didn't work. Here's the compiled code. It includes an OS-function but it's not that easy to call it up because I don'T know where the function starts (It doesn't look like it starts at offset 0x00). code532.rar



First I thought there'd be such an instruction set in the PPC library...

[Pyriel]

By PPC library, you mean the processor instruction set? If so, no, nothing that high-level is typically defined so close to the metal. It might be accomplished by a syscall of some sort, but that's system dependent, and you'd have to figure out how to issue such a call on the Wii U. That's about as low-level as you can get for text or graphical displays.