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