a2d/desktop

DeskTop diassembly notes

DESKTOP.SYSTEM

A short (8k) loader program. This is likely responsible for copying the rest to a RAM card (if available), then invoking the main app.

DESKTOP2.$F1

This is large - 111k. It includes a loader, the DeskTop app (with both main memory and aux memory segments, filling everything from $4000 to $FFFF (except for I/O space and ProDOS), and still having more code - probably the disk copy code which is swapped in dynamically.

The file is broken down into multiple segments:

• segment 0: load - offset $0000, length $0580, loaded at $2000
• segment 1: aux1 - offset $0580, length $8000, loaded at $4000 (through $BFFF)
• segment 2: aux2 - offset $8580, length $1D00, loaded at $D000 (through $ECFF)
• segment 3: aux2 - offset $A280, length $0500, loaded at $FB00 (through $FFFF)
• segment 4: main - offset $A780, length $7F00, loaded at $4000 (through $BEFF)
  • main $BF00-$BFFF is ProDOS buffers
  • main $C000-$CFFF is I/O space
  • main $D000-$FFFF is ProDOS
• segment 5: TBD - 38k so must be further subdivided.

Much of the space is data:

• API jump table at $40E5, param details at $4184
• Font is at $8800

Icon bitmaps are at $FF00-ish (.SYSTEM file is $FF06), stride 5, $22x$11px