TODO
| Address | Description |
|---|---|
| 0x401 | Extended memory between 0x100000 and 0xFFFFFF, in units of 128 KB |
| 0x43B | bit 2 - 0 if memory hole between 15 and 16MB present, 1 otherwise; TODO |
| 0x501 | BIOS flags: bits 0-2 - conventional memory size, in units of 128 KB; bit 3 - 1 if high resolution system; bits 4-6 TODO; bit 7 - 1 if 2.4576MHz timer; 0 if 1.9968MHz timer |
| 0x52A-0x539 | Keyboard matrix |
| 0x538 | Keyboard shift status (see INT 18h AH=02h) |
| 0x594 - 0x595 | Extended memory above 0xFFFFFF, in units of 1 MB |