The new `dispatcher_no_timing_check` is the same as `dispatcher_no_check`
except it includes the "stepping check" in debug mode. This lets us avoid
the `m_enable_debugging ? dispatcher : dispatcher_no_check` dance.
Maybe "tail call" isn't quite the right term for what this code
is doing, since it's jumping to the dispatcher rather than
returning, but it's the same optimization as for a tail call.
fregsIn will include FD for double-precision instructions, since for
dependency tracking purposes the instruction does read the upper
half of FD. This is not what we want in HandleNaNs.
The consequence of this bug is that if an instruction was supposed to
output a NaN and FD happens to contain a NaN and FD happens to be the
same register as an unused register in the instruction encoding, the
NaN in FD could get used as the output instead of the correct NaN.
This isn't known to affect any games, which isn't especially surprising
considering that there's only one game that needs AccurateNaNs anyway.
Jumping to `dispatcher` requires first subtracting the downcount,
otherwise `dispatcher` may unpredictably jump to CoreTiming::Advance,
which could break determinism compatibility with JitArm64. We should
jump to `dispatcher_no_check` instead.
The breakpoint check in Jit.cpp makes it redundant.
Normally this redundant check doesn't cause any issues, but if you
create a breakpoint and enable logging without breaking, you get two
log messages if the breakpoint is at the beginning of a block. See
https://bugs.dolphin-emu.org/issues/13044.
This is also a tiny performance improvement for when debugging is
active, since we no longer check for breakpoints for blocks that never
had any breakpoints to begin with.
base is an unsigned variable, so we can make things little more
consistent by making the loop index unsigned so we aren't doing bit
arithmetic with signed types.
MemoryInterface already does this, so we can leave it alone.
No behavioral changes, just a consistency thing.
Micro-optimization. Some CPUs can fuse CMP+B, TST+B, arith+CBZ, etc.
I also moved things around for CMP+CSET and TST+CSET - which I'm not sure
if any CPUs support - but it doesn't hurt anything, so I might as well.
Improves accuracy but isn't known to affect any games.
This turned out to be fairly convenient to implement; ORing with the
PPC default NaN will quieten SNaNs and do nothing to QNaNs.
This existed in the initial megacommit (though I don't know why) as IO_SIZE. It was used in Memmap's Init() to compute totalMemSize, but I don't know if it actually did anything then. That use was removed in 2d0f714546, but the constant persisted until cc858c63b8, when it became a static variable.
This was added in 385d8e2b15, but became somewhat redundant with Do in 4c7bbd96e4, and completely redundant now that std::is_trivially_copyable_v is well-supported.
