byuu says:
Changelog:
- added nall/bit-field.hpp
- updated all CPU cores (sans LR35902 due to some complexities) to use
BitFields instead of bools
- updated as many CPU cores as I could to use BitFields instead of union {
struct { uint8_t ... }; }; pairs
The speed changes are mostly a wash for this. In some instances,
I noticed a ~2-3% speedup (eg SNES emulation), and in others a 2-3%
slowdown (eg Famicom emulation.) It's within the margin of error, so
it's safe to say it has no impact.
This does give us a lot of new useful things, however:
- no more manual reconstruction of flag values from lots of left shifts
and ORs
- no more manual deconstruction of flag values from lots of ANDs
- ability to get completely free aliases to flag groups (eg GSU can
provide alt2, alt1 and also alt (which is alt2,alt1 combined)
- removes the need for the nasty order_lsbN macro hack (eventually will
make higan 100% endian independent)
- saves us from insane compilers that try and do nasty things with
alignment on union-structs
- saves us from insane compilers that try to store bit-field bits in
reverse order
- will allow some really novel new use cases (I'm planning an
instant-decode ARM opcode function, for instance.)
- reduces code size (we can serialize flag registers in one line instead
of one for each flag)
However, I probably won't use it for super critical code that's constantly
reading out register values (eg PPU MMIO registers.) I think there we
would end up with a performance penalty.
byuu says:
Alright, well interrupts are in. At least Vblank is.
I also fixed a bug in vector() indexing, MoDRM mod!=3&®==6 using SS
instead of DS, opcodes a0-a3 allowing segment override, and added the
"irq_disable" stuff to the relevant opcodes to suppress IRQs after
certain instructions.
But unfortunately ... still no go on Riviera. It's not reading any
unmapped ports, and although it enables Vblank IRQs and they set port
$b4's status bit, the game never sets the IE flag, so no interrupts ever
actually fire. The game does indeed appear to be sitting in a rather
huge loop, which is probably dependent upon some RAM variable being set
from the Vblank IRQ, but I don't know how I'm supposed to be triggering
it.
... I'm really quite stumped here >_>
byuu says:
All 256 instructions implemented fully. Fixed a major bug with
instructions that both read and write to ModRM with displacement.
Riviera now runs into an infinite loop ... possibly crashed, possibly
waiting on interrupts or in to return something. Added a bunch of PPU
settings registers, but nothing's actually rendering with them yet.
Tim Allen