sinamas 1a0ce36a69 libgambatte: speed change re work
Findings of note:
- The LCD (PPU) can seemingly end up at a cycle offset relative to the
CPU that is a non-multiple of 4 when switching away from double speed
mode (as compared with normal). The behaviour appears equivalent to a
CPU tick being skipped relative to the LCD/PPU, which can result in 2
different offsets depending on whether the speed change is done at an
odd M-cycle (i.e. an odd multiple of 4 cycles in double speed mode).
This will also seemingly carry over to double speed mode upon another
speed change, and, repeated speed changes can seemingly produce all 4
offsets.
2019-09-30 17:45:53 +02:00
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