This is based on the MIPS dynarec (more or less) with some ARM
borrowings. Seems to be quite fast (under my testing fixed results:
faster than ARM on A1 but not a lot faster than the interpreter on
Android Snapdragon 845) but still some optimizations are missing at the
moment.
Seems to pass my testing suite and compatibility wise is very similar to
arm.
This gets rid of the bloated memmap_win32.c in favour of a much simpler
wrapper. This will be needed in the future since the wrapper does not
support MAP_FIXED maps (necessary for some platforms)
This removes one branch and emits the region selection code directly in
the JIT cache. Trading memory for speed (although it's not a big
improvement).
This is a step towards enabling MMAP caches in ARM (due to the 32MB
offset limitation in branches).
This introduced a potential race condition between the start of a SWI
and the BIOS handling the exception by returning to system mode. During
this ~10 instruction window, having an IRQ that issues a SWI causes bad
behaviour that results in crashes or other weirdness.
Fixes a couple of games and potentially many weird and obscure bugs here
and there (hard to reproduce sometimes).
This fixes a race condition that happens whenever the ROM cache is flushed but
the RAM one is not, causing any SWI calls (implemented as direct branches) to
jump to random instructions.
The fix could be to flush both caches at the same time (~expensive on
low mem platforms), use indirect jumps (a bit expensive) or emit the SWI
handler below the watermark to ensure it is never flushed. This is cheap
and effective, requires minimal changes.
This mis-emits CMN instead of TEQ and TST in the reg-shift operand mode.
This is never used by gpsp directly but translating real tst opcodes,
hence it only affects games using such instruction.
This fixes video players that previously crashed, many games that had
graphical glitches in ARM mode (but not on other CPUs) usually in menus
or other dialogues. Also fixes games that either crashed or went blank
or similar issues. The extent of fixing is hard to determine but could
affect many games in different levels.
Removed the last bits of text relocations by moving all relevant RAMs to
the stub reachable area. This should be as fast or even faster than
previous code.
This fixes unallowed BIOS accesses (outside from BIOS) which fixes some
games like Silent Scope but also Zelda (fixes rolling as reported by
neonloop!)
This removes ram_block_ptrs and encodes the pointer directly in the
block tag. Saves ~256KB at no performance cost.
Drawback is that it limits the ram cache size to 512KB (we were using
768KB before). Should not be a problem since most games use less than
32KB of cache anyway.
Fixed ARM routines accordingly.
This might make a handful games slightly slower (but on the upper side
they work now instead of crashing or restarting).
Also while at it, fix some minor stuff in arm stubs for speed.
Cleans up a ton of whitespace in cpu.c (like 100KB!) and improves
readability of some massive decode statements.
Added an optimization for PC-relative loads (pool load) in ROM (since
it's read only and cannot possibily change) that directly emits an
immediate load. This is way faster, specially in MIPS/x86, ARM can be
even faster if we rewrite the immediate load macros to also use a pool.
Using an invalid SP makes Vita crash (for an unkown reason) and makes
things like C signal handlers crash (luckily Retroarch doesn't use
them). It is also a violation of the ABI and not a great idea.
Recycled some little used registers to free SP. Perf should be roughly
the same.
Seems that using the __atribute__ magic for sections is not the best way
of doing this, since it injects some default atributtes that collide
with the user defined ones. Using assembly is far easier in this case.
Reworked definitions a bit to make it easier to import from assembly.
Also wrapped stuff around macros for easy and less verbose
implementation of the symbol prefix issue.
This saves a few cycles in MIPS and simplifies a bit the core.
Removed the write map, only affects interpreter performance very
minimally. Rewired ARM and x86 handlers to support direct access to
I/EWRAM (and VRAM on ARM) to compensate. Overall performance is slightly
better but code is cleaner and allows for further improvements in the
dynarecs.
David Guillen Fandos