byuu says:
Changelog:
- md/ym2612: initialize DAC sample to center volume [Cydrak]
- processor/arm: add accumulate mode extra cycle to mlal [Jonas
Quinn]
- processor/huc6280: split off algorithms, improve naming of functions
- processor/mos6502: split off algorithms
- processor/spc700: major revamp of entire core (~50% completed)
- processor/wdc65816: fixed several bugs introduced by rewrite
For the SPC700, this turns out to be very old code as well, with global
object state variables, those annoying `{Boolean,Natural}BitField` types,
`under_case` naming conventions, heavily abbreviated function names, etc.
I'm working to get the code to be in the same design as the MOS6502,
HuC6280, WDC65816 cores, since they're all extremely similar in terms of
architectural design (the SPC700 is more of an off-label
reimplementation of a 6502 core, but still.)
The main thing left is that about 90% of the actual instructions still
need to be adapted to not use the internal state (`aa`, `rd`, `dp`,
`sp`, `bit` variables.) I wanted to finish this today, but ran out of
time before work.
I wouldn't suggest too much testing just yet. We should wait until the
SPC700 core is finished for that. However, if some does want to and
spots regressions, please let me know.
byuu says:
Changelog:
- rewrote the 6502 CPU core from scratch. Now called MOS6502,
supported BCD mode
- Famicom core disables BCD mode via MOS6502::BCD = 0;
- renamed r65816 folder to wdc65816 (still need to rename the actual
class, though ...)
Note: need to remove build rules for the now renamed r6502, r65816
objects from processor/GNUmakefile.
So this'll seem like a small WIP, but it was a solid five hours to
rewrite the entire 6502 core. The reason I wanted to do this was because
the old 6502 core was pretty sloppy. My coding style improved a lot, and
I really liked how the HuC6280 CPU core came out, so I wanted the 6502
core to be like that one.
The core can now support BCD mode, so hopefully that will prove useful
to hex\_usr and allow one core to run both the NES and his Atari 2600
cores at some point.
Note that right now, the core doesn't support any illegal instructions.
The old core supported a small number of them, but were mostly the no
operation ones. The goal is support all of the illegal instructions at
some point.
It's very possible the rewrite introduced some regressions, so thorough
testing of the NES core would be appreciated if anyone were up for it.
Tim Allen