Port assembly to C.

Post by **Nach** » Fri Feb 04, 2005 5:22 am

We need to port more to C, and we simply don't have enough people doing this. If you have a decent understanding of assembly and C, and have some free time, please help us port some code.

Currently, it would be appreciated if someone would port one or more of these file:

ui.asm (Easy)
guicheat.inc (Pretty Easy)
guinetpl.inc (Difficult)
guiload.inc (Difficult)

Noxious Ninja · Post by **Noxious Ninja** » Fri Feb 04, 2005 4:10 pm

I'm currently working through my C course book again, then I'd like to give something a try.

TheDanish · Post by **TheDanish** » Mon Feb 07, 2005 4:17 pm

I'd like to try ui.asm to get my n00bish feet wet, if it hasn't been taken yet. I've ported a few functions successfully just to make sure I could, so I have just one question for the time being: would you like the functions to do exactly what they would in assembly, or would you like them to follow C semantics? If it's straight C, then obviously other files need to be changed to accommodate. For example, if a function takes eax as an argument, would you like the C function to actually get eax, or would you want all the calls changed to push eax first? I'm guessing the latter, but I just want to be sure. Any other details I need to know would obviously be good to know, too.

Also, I'm kind of busy with college, so it would be awhile between that and the fact that I'm learning as I go. If I get ui done in a timely manner, I should be comfortable with the environment enough to do whatever's left.

Post by **Nach** » Mon Feb 07, 2005 4:25 pm

TheDanish wrote:I'd like to try ui.asm to get my n00bish feet wet, if it hasn't been taken yet.

Well some people have been working on part of it. Just do a few functions at a time that haven't been taken yet, and send them to me. Basically, if it's in the assembly in CVS, it hasn't been taken yet.

TheDanish wrote: I've ported a few functions successfully just to make sure I could, so I have just one question for the time being: would you like the functions to do exactly what they would in assembly, or would you like them to follow C semantics? If it's straight C, then obviously other files need to be changed to accommodate. For example, if a function takes eax as an argument, would you like the C function to actually get eax, or would you want all the calls changed to push eax first? I'm guessing the latter, but I just want to be sure.

Don't care that much really, although I don't see how you're going to make a function actually read eax in a portable way. Here's the general rule:
If it's one parameter which is an int or a pointer, pass by parameter by pushing eax or whatever. If it's not that type or there are two parameters, pass by global vars.

TheDanish wrote: Any other details I need to know would obviously be good to know, too.

Just as soon as you make a few function changes that are working, submit them so no one else will try to port the same stuff.

BTW, if you need to call a parameterless assembly function from C, include the new header asm_call.h and do asm_call(func_name);

TheDanish · Post by **TheDanish** » Mon Feb 07, 2005 4:43 pm

Alright, sure. Thanks for clearing it up.

TheDanish · Post by **TheDanish** » Tue Feb 08, 2005 6:04 pm

Nach, check your PMs?

quad · Post by **quad** » Sun Mar 06, 2005 7:00 pm

Hi,

This is my first post here.

I have been interested in various emulation aspects since a couple of years now, and have always found ZSNES to be the best SNES emulator out there -- especially since it has been ported to UNIX. ;P Being a developer myself, I thought that hacking into this emulator code could be interesting. My main goal is to implement some kind of debugging process into ZSNES for the UNIX version (breakpoints, memory watches, etc.). (And speaking of that, has there been any work previously done for this?)

I gave it a try at porting assembly code to C a month or so ago. It was done on release version 1.42, but today I've merged my changes to the latest CVS files. I mainly extracted a few functions from src/linux/sdlintrf.asm to a new file src/linux/sdlintrf-c.c. It compiles fine and games still seems to work. ;P

Now the question is how should I proceed to submit a patch? Or just submit the files themselves to someone (Nach?) ? Thanks for any information and keep up the good work.

Aerdan · Post by **Aerdan** » Sun Mar 06, 2005 7:17 pm

As far as debugging goes, look at ./autogen.sh --enable-debug.

You may want to put a copy of the files changed up somewhere so grin or nach can look at it.

quad · Post by **quad** » Sun Mar 06, 2005 8:02 pm

But isn't ./autogen.sh --enable-debug for enabling debugging of the zsnes executable? Coincidentally I tried this switch in order to debug zsnesd with gdb. Argh, I might have expressed myself incorrectly -- I actually want to implement debugging at the ROM (game) level, much like the DOS -d option works (though I never had the opportunity to try it really ;P). I'd like to keep it simple for UNIX: something similar to gdb, in a command line fashion, since I'm not that good at writing GUI stuff.

As for the changes, I'll diff them and post it somewhere soon. Thanks!

Edit: A patch file (zsnes.diff) and a new file (sdlintrf-c.c) are located at the following address:
quadhome.calizone.net:8000/zsnes/

All comments are welcome!

Aerdan · Post by **Aerdan** » Mon Mar 07, 2005 1:42 am

Look at debug.asm in dos/.

Post by **grinvader** » Tue Mar 08, 2005 3:50 pm

Aerdan wrote:Look at debug.asm in dos/.

Ahoy, Pagefault has started working on a non dos-only debugger. Check debug.c in latest cvs.