mirror of https://github.com/bsnes-emu/bsnes.git
3 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Allen
|
b73d918776 |
Update to v102r25 release.
byuu says:
Changelog:
- processor/arm: corrected MUL instruction timings [Jonas Quinn]
- processor/wdc65816: finished phase two of the rewrite
I'm really pleased with the visual results of the wdc65816 core rewrite.
I was able to eliminate all of the weird `{Boolean,Natural}BitRange`
templates, as well as the need to use unions/structs. Registers are now
just simple `uint24` or `uint16` types (technically they're `Natural<T>`
types, but then all of higan uses those), flags are now just bool types.
I also eliminated all of the implicit object state inside of the core
(aa, rd, dp, sp) and instead do all computations on the stack frame with
local variables. Through using macros to reference the registers and
individual parts of them, I was able to reduce the visual tensity of all
of the instructions. And by using normal types without implicit states,
I was able to eliminate about 15% of the instructions necessary, instead
reusing existing ones.
The final third phase of the rewrite will be to recode the disassembler.
That code is probably the oldest code in all of higan right now, still
using sprintf to generate the output. So it is very long overdue for a
cleanup.
And now for the bad news ... as with any large code cleanup, regression
errors have seeped in. Currently, no games are running at all. I've left
the old disassembler in for this reason: we can compare trace logs of
v102r23 against trace logs of v102r25. The second there's any
difference, we've spotted a buggy instruction and can correct it.
With any luck, this will be the last time I ever rewrite the wdc65816
core. My style has changed wildly over the ~10 years since I wrote this
core, but it's really solidifed in recent years.
|
|
|
Tim Allen
|
6e8406291c |
Update to v102r24 release.
byuu says
Changelog:
- FC: fixed three MOS6502 regressions [hex\_usr]
- GBA: return fetched instruction instead of 0 for unmapped MMIO
(passes all of endrift's I/O tests)
- MD: fix VDP control port read Vblank bit to test screen height
instead of hard-code 240 (fixes Phantasy Star IV)
- MD: swap USP,SSP when executing an exception (allows Super Street
Fighter II to run; but no sprites visible yet)
- MD: grant 68K access to Z80 bus on reset (fixes vdpdoc demo ROM from
freezing immediately)
- SFC: reads from $00-3f,80-bf:4000-43ff no longer update MDR
[p4plus2]
- SFC: massive, eight-hour cleanup of WDC65816 CPU core ... still not
complete
The big change this time around is the SFC CPU core. I've renamed
everything from R65816 to WDC65816, and then went through and tried to
clean up the code as much as possible. This core is so much larger than
the 6502 core that I chose cleaning up the code to rewriting it.
First off, I really don't care for the BitRange style functionality. It
was an interesting experiment, but its fatal flaw are that the types are
just bizarre, which makes them hard to pass around generically to other
functions as arguments. So I went back to the list of bools for flags,
and union/struct blocks for the registers.
Next, I renamed all of the functions to be more descriptive: eg
`op_read_idpx_w` becomes `instructionIndexedIndirectRead16`. `op_adc_b`
becomes `algorithmADC8`. And so forth.
I eliminated about ten instructions because they were functionally
identical sans the index, so I just added a uint index=0 parameter to
said functions. I added a few new ones (adjust→INC,DEC;
pflag→REP,SEP) where it seemed appropriate.
I cleaned up the disaster of the instruction switch table into something
a whole lot more elegant without all the weird argument decoding
nonsense (still need M vs X variants to avoid having to have 4-5
separate switch tables, but all the F/I flags are gone now); and made
some things saner, like the flag clear/set and branch conditions, now
that I have normal types for flags and registers once again.
I renamed all of the memory access functions to be more descriptive to
what they're doing: eg writeSP→push, readPC→fetch,
writeDP→writeDirect, etc. Eliminated some of the special read/write
modes that were only used in one single instruction.
I started to clean up some of the actual instructions themselves, but
haven't really accomplished much here. The big thing I want to do is get
rid of the global state (aa, rd, iaddr, etc) and instead use local
variables like I am doing with my other 65xx CPU cores now. But this
will take some time ... the algorithm functions depend on rd to be set
to work on them, rather than taking arguments. So I'll need to rework
that.
And then lastly, the disassembler is still a mess. I want to finish the
CPU cleanups, and then post a new WIP, and then rewrite the disassembler
after that. The reason being ... I want a WIP that can generate
identical trace logs to older versions, in case the CPU cleanup causes
any regressions. That way I can more easily spot the errors.
Oh ... and a bit of good news. v102 was running at ~140fps on the SNES
core. With the new support to suspend/resume WAI/STP, plus the internal
CPU registers not updating the MDR, the framerate dropped to ~132fps.
But with the CPU cleanups, performance went back to ~140fps. So, hooray.
Of course, without those two other improvements, we'd have ended up at
possibly ~146-148fps, but oh well.
|
|
|
Tim Allen
|
cea64b9991 |
Update to v102r23 release.
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.
|