We compile the blocks as they are executed, so it's common
to link them continuously. We end with calling JMP after every
block, but often just with a distance of 0.
So just emitting NOPs instead also "calls" the next block, but
easier for the CPU.
They weren't sufficient and are made redundant by previous commits; they
also (on master) caused breakage due to Jit64::psq_stXX assuming writes
would be fastmem and not clobber a register under certain conditions.
That really needs to be refactored, but for now, this works.
Without fastmem, the JIT code still does an inline check for RAM
addresses. With watchpoints we have to disable that too. (Hardware
watchpoints would avoid all the slow, but be complicated to implement
and limited in number - I doubt most people debugging games care much if
they run slower.)
With this change and watchpoints enabled, Melee runs at no more than 40%
speed, despite running at full speed without them. Oh well. Better
works slowly than doesn't bloody work.
Incidentally, I'm getting an unrelated crash in
PowerPC::HostIsRAMAddress when shutting down a game. This code sucks.
- Move JitState::memcheck to JitOptions because it's an option.
- Add JitOptions::fastmem; switch JIT code to checking that rather than
bFastmem directly.
- Add JitBase::UpdateMemoryOptions(), which sets both two JIT options
(replacing the duplicate lines in Jit64 and JitIL that set memcheck
from bMMU).
- (!) The ARM JITs both had some lines that checked js.memcheck
despite it being uninitialized in their cases. I've added
UpdateMemoryOptions to both. There is a chance this could make
something slower compared to the old behavior if the uninitialized
value happened to be nonzero... hdkr should check this.
- UpdateMemoryOptions forces jo.fastmem and jo.memcheck off and on,
respectively, if there are any watchpoints set.
- Also call that function from ClearCache.
- Have MemChecks call ClearCache when the {first,last} watchpoint is
{added,removed}.
Enabling jo.memcheck (bah, confusing names) is currently pointless
because hitting a watchpoint does not interrupt the basic block. That
will change in the next commit.
