Review follow-up on #661 (#636):
- test_depth24_present_hold_vblank.py reads sources as UTF-8 (cp1252 on
native Windows Python raised UnicodeDecodeError).
- The present skip is now guest state: set at guest VBlank, read (not
consumed) by the present and packed into the GPU snap's hold word (bit 8;
older snaps derive it from the count). The executable test showed the
host-side latch made the present of a restored tick differ from live on
the last held VBlank (hold 0, skip 1), exposing stale trailing FMV
columns after a rollback load.
- Depth24 scanout staging and trailing-column blanking move from main.cpp
into gpu_depth24_stage_scanout (gpu.c), so the test renders through the
same code every CPU depth24 present runs.
- New depth24_present_hold_exec_test: drives real gpu.c through a 15-bit to
24-bit FMV, GP1(07h) retargets and mode transitions; compares hold, skip,
upload span and snapshot bytes across windowed/headless/deferred presents,
rollback replay from every tick and disk loads, and checks staged frames
never show stale movie pixels while the new movie stays visible.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Matthew Stanley