Finished off the GUI changes for the next release, and fixed a few audio issues. Still trying to figure out wtf is happening with the channel volume though, something’s not quite right there…
Changes

• Finished rewriting the debug GUI to cooperate with the new main window – last remnants of glade-generated code are now gone.
• More work on the controller settings dialog – it’s useable now (well, useable as in “it’s possible to use it” anyway), works, etc.
• Fixed freelist bug in texcache (I don’t know how its gone so long without being triggered before, but…)
• Fixed AICA save state data (wasn’t saving the channel or IO data)
• Implemented AICA channel status registers

It’s been a GUI kind of week…

Changes

• Maintain aspect-ratio when resizing window
• Simplify command line – “lxdream disc-image” now boots off the specified disc.
• Config file now loaded/saved from home directory by default, with system defaults in the sysconfdir.
• Improve keyboard support to use unmodified key values (ie z and shift-z are now interpreted the same way).
• Add initial controller settings dialog
• Add path settings dialog
• Unbreak the debugger (although the translator still doesn’t play well with it)
• Add CDI V3.5 support (0×80000006) – looks to be barely distinct from V3 anyway.

I tracked down an ugly bug that only appeared in optimized builds to some highly dodgy code that’s probably been there since nearly the start of the project. As a result, it seemed like it might be a good idea to start building with -Wall, and actually fix the warnings (shock horror). Fixed a couple of real bugs in the process too. I also dug a little bit into the sound system (for the first time in nearly a year) and got the boot sound to play. Well, for a couple of seconds before it breaks into noise at least – there’s still some issues there.

The biggest performance problem now appears to be the rendering code. For some typical scenes it’s taking 30-40ms/frame, where the original budget was around 25% cpu, or <5ms per frame. Yeah, it's bad. Working on it ^_^.
Changes

• Fix (nearly) all of the compilation warnings gcc was generating under -Wall. Including a couple of actual bugs, which was nice.
• Fix ADPCM sound to at least sort of work.
• Fix AICA key-on/key-off behaviour.
• First draft of shiny new GUI (unfortunately debugger is broken at the moment, not sure if its worth fixing – does anyone actually want it?)
• Add support for output scaling
• Clean out a batch of obsolete cruft from the video driver.

Fixed some minor bugs and improved the speed a little more – overall core speed is now roughly double that of M3 – not bad for a couple of weeks work. For certain use cases the system now runs at nearly 100% speed (under the unlikely assumption of 100,000,000 instructions/second[0]). Unfortunately I think I’ve just about tapped out the low-hanging fruit – further performance gains are likely to be obtained inch by painful inch.

My plan for the moment is to get a decent user UI up and running, fix some of the nastier audio + video bugs, and shoot for an interim release later this month. It’d be particularly nice if the bootup sound was approximately correct (now that things are fast enough that you can actually tell that its b0rked).

Changes

• Fix more translation cache bugs
• Fix controller triggers (sense was inverted)
• Remove MMU AT checks from sh4mem.c (needs to be in core anyway for exception correctness). Also #define out the trace checks by default – slight performance gain.
• Add explicit branches in sh4mem.c for main memory access – it’s actually faster this way, if less flexible.
• Fix save state loader bug (SH4).
• Add command-line opt to change the SH4 speed scaling
• Remove instruction counter in ESI (change to constant loads where needed)
• Suppress redundant flag loads

[0] Bloody complicated superscalar pipeline design… real code could run at anywhere between 10 MIPS and 400 MIPS for a 200Mhz clock. Getting even approximate cycle accuracy would be nice, just as soon as I have an efficient way to implement it.