CPU tasks done and other progress (Patreon)

Hi everyone,

the picture above might not be very exciting, but is indeed ia big step.

It's from the CPU tests of Amidog. You can find a summary on how different emulators pass it here(table CPU tests with 101 subtests):

https://emulation.gametechwiki.com/index.php/PS1_Tests

The PSX core also passes all 101 CPU tests now, which not only means that all CPU functionality required for games is there, but also that lots of edge case behavior is already working right. I'm really happy to see that, because if a bug occurs now, it's most likely not some CPU miscalculation.

What else happened? Since the last post is 2 weeks in the past, quiet a lot. 

In total I made 26 changes or fixes. Here is a summary:

- GPU now supports VRAM readback from CPU and DMA. This was the last big module missing in the GPU. Everything else now are tiny bits, like dithering or texture masks that do not alter the program flow, so I will postpone them a bit.

- GTE work has started. All registers are implemented and the first of 22 GTE commands is working. Communition with the CPU also works.

- More register areas can now be accessed by the CPU, e.g. registers for serial connection. They are typically not used by games, but games will hang if they cannot read and write them.

- CPU now has it's datacache(scratchpad) and also received many many bugfixes to make all the tests pass.

I can now finally concentrate on the GTE. When this is done we might finally see the BIOS booting up?

Have fun!