This accounts for DMA stealing cycles from the CPU whenever the CPU
triggers a DMA (does not affect H/V blank or sound DMAs).
Works by moving the CPU to a PAUSED state where the cycles are accounted
for, reusing a similar mechanism for HALT/STOP.
Fixes a couple of games, notably GTA that has a DMA/IRQ race condition
(likely a bug really) if cycles are grossly miscalculated.
This rewrites the way that CPU alerts work, making them a bitmap (since
multiple alerts can happen simultaneously, like SMC and IRQ). This
doesn't really fix many games but improves accuracy overall and improves
performance on some I/O writes (the ones without side effects).
The IRQ raising is now decoupled and explicitely called via a new
function (check_and_raise_interrupts) to avoid issues such as invalid
CPSR values (doesn't seem to bother most games!). There's more side
effects missing, so this just lays the ground for more fixes.
This fixes ROM swapping for x86/64, arm32 and arm64. On top of that it
improves speed by removing unnecessary slow paths on small ROMs for
arm32 and mips. If the ROM can fit in RAM, it will emit more efficient
code that assumes the ROM is fully loaded.
For low-memory Linux platforms it would be better to use some mmap'ed
ROM, that way the OS would transparently handle page swapping, which is
perhaps faster. Will investigate and follow up on this in a separate
commit.
gpsp doesn't differentiate between USER and SYSTEM mode, most likely
cause it is not that important for most games. This implements the modes
correctly and adds checks for privileged operations. Still some
bugs/hacks but it mostly fixes CPSR/SPSR reads/writes.
To implement PSR writes we are using a more refined masks and force mode
bit num. 4 to always be one. Reserved bits are forced to zero (this
needs to be validated on a real device).
Converted the hack into another... hopefully better hack.
Check for IW/EWRAM addr bit and handle accesses to EWRAM by correcting
the base addr and the mirroring range.
Assumes that iwram and ewram buffers are at a distance multiple of 64KB
for speed (so that lw/sw offsets can be shared).
This fixes a variety of games that should have been present in
game_config.txt such as Ninja Cop, Star Wars JPB, Medal of Honor,
Spongebob, etc. Some of them were just missing regional versions of the
cart. It also fixes newer games and homebrew such as GoodBoy Galaxy.
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)
David Guillen Fandos