Repro:
- Configure a system with Super Serial Card in Slot 1 and Serial Printer. (NOTE: Reproduces in MAME, but not Virtual ][)
- Launch DeskTop
- Extras > Screen.Dump
Look at the File menu on completion:
Analysis:
When the accessory is started, DeskTop "highlights" the File menu (via a call to MGTK::HiliteMenu) because the command File > Open is running. The accessory explicitly unhighlights the menu during the screen dump so that it doesn't show in the output, then re-highlights it on completion. DeskTop then unhighlights it again.
However, something goes wrong and the File menu ends up corrupted.
The proximal cause seems to be that the SSC utilizes the Slot 1 screen holes for temporary storage, and MGTK is also using these bytes for part of its expanded pattern buffer. When the SSC is in use the screen holes are modified, leading to a corrupted pattern. It's possible that the optimization in 4c6527a made this more obvious. But regardless... reading or writing to the screen holes is a bad idea; if a disk drive's holes are touched, badness could happen.
Repro:
Look at the File menu on completion:
Analysis:
When the accessory is started, DeskTop "highlights" the File menu (via a call to
MGTK::HiliteMenu) because the command File > Open is running. The accessory explicitly unhighlights the menu during the screen dump so that it doesn't show in the output, then re-highlights it on completion. DeskTop then unhighlights it again.However, something goes wrong and the File menu ends up corrupted.
The proximal cause seems to be that the SSC utilizes the Slot 1 screen holes for temporary storage, and MGTK is also using these bytes for part of its expanded pattern buffer. When the SSC is in use the screen holes are modified, leading to a corrupted pattern. It's possible that the optimization in 4c6527a made this more obvious. But regardless... reading or writing to the screen holes is a bad idea; if a disk drive's holes are touched, badness could happen.