Thursday, December 24, 2009

There's been more planning and thinking than actual work lately. I've reached a point where I'm not sure what to work on next. I think the next items are going to be heap managent or process management, file interface or something like that.

I've changed the ABI to make R13, R14 and R15 non-volatile. This was done to make blwp and xop reasonable to use. I was working on the system call interface, and was annoyed by the amount of work needed to make the system work if those registers were kept as volatile. R12 has been made volatile to support easy CRU operation. Originally, that was a non-volatile register. using CRU instrustions incurred a similar level of annoyance. So now the register usage looks like this: R0-R8,R12 are volatile, R10,R11, R13-R15 are non-volatile. Basically, all special-purpose registers are non-volatile except R12. R9 has no special purpose, but I figured I should keep it non-volatile anyways.

As mentioned above, I've added a system call interface to the project. It doesn't actually do anything useful, but it works. I keep thinking that if I restrict the *print* calls to the system call interface, I can save 120 bytes. I'll make a final decision on this later.

I'm currently looking at heap management algorithms, so I guess that will be next.

Just for the heck of it, I've been thinking about a wolf-3d clone for the TI. I'm not sure if I'll actually do it, since I've got a lot going on right now, but it willl give me a better idea of what real-world programs will need.

I've also been thinking about writing a compiler best-practices guide as I continue working. I keep going back to Tursi's GCC port and his misguided insistance on a zero register, At some point I would like a C compliler, and I would like it to be good.

No comments:

Post a Comment