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back2root:ibm-pc-ms-dos:interrupts:int_11:start
Table des matières
Interruption 11h - BIOS Equipment Determination / BIOS Equipment Flags
Request/Call:
no input data
Return:
| reg | descr |
|---|---|
| AX | contains followings bit flags |
Values code:
| bit | description | specific PS/2 |
|---|---|---|
| 0 | IPL diskette installed | |
| 1 | math coprocessor | |
| 2 | old PC system board RAM < 256K | pointing device installed (PS/2) |
| 3 | not used | |
| 4-5 | initial video mode | |
| 6-7 | # of diskette drives, less 1 | |
| 8 | 0 if DMA installed | |
| 9-11 | number of serial ports | |
| 12 | game adapter installed | |
| 13 | unused | internal modem (PS/2) |
| 14-15 | 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 - 40×25 color
- 10 - 80×25 color
- 11 - 80×25 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
Notes & Comments
- 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
back2root/ibm-pc-ms-dos/interrupts/int_11/start.txt · Dernière modification : 2024/04/06 18:45 de frater
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