Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
INT 11 - BIOS Equipment Determination / BIOS Equipment Flags
no input data
on return:
AX contains the following bit flags:
│F│E│D│C│B│A│9│8│7│6│5│4│3│2│1│0│ AX
│ │ │ │ │ │ │ │ │ │ │ │ │ │ │ └──── IPL diskette installed
│ │ │ │ │ │ │ │ │ │ │ │ │ │ └───── math coprocessor
│ │ │ │ │ │ │ │ │ │ │ │ └─┴────── old PC system board RAM < 256K
│ │ │ │ │ │ │ │ │ │ │ │ │ └───── pointing device installed (PS/2)
│ │ │ │ │ │ │ │ │ │ │ │ └────── not used on PS/2
│ │ │ │ │ │ │ │ │ │ └─┴─────── initial video mode
│ │ │ │ │ │ │ │ └─┴────────── # of diskette drives, less 1
│ │ │ │ │ │ │ └───────────── 0 if DMA installed
│ │ │ │ └─┴─┴────────────── number of serial ports
│ │ │ └─────────────────── game adapter installed
│ │ └──────────────────── unused, internal modem (PS/2)
└─┴───────────────────── number of printer ports
- bits 3 & 2, system board RAM if less than 256K motherboard
00 - 16K 01 - 32K
10 - 16K 11 - 64K (normal)
- bits 5 & 4, initial video mode
00 - unused 01 - 40x25 color
10 - 80x25 color 11 - 80x25 monochrome
- bits 7 & 6, number of disk drives attached, when bit 0=1
00 - 1 drive 01 - 2 drives
10 - 3 drive 11 - 4 drives
- returns data stored at BIOS Data Area location 40:10
- some flags are not guaranteed to be correct on all machines
- bit 13 is used on the PCjr to indicate serial printer
[helppc.bosbyte.nl] equipment flags