User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 190
Continued
AH = 11h Return extended buffer status.
Exit:
AL ASCII keystroke pressed
AH Scan code of key
ZF No keystroke available
NZ Keystroke in buffer
AH = 12h Return extended shift status.
Exit:
AL Shift status:
Bit 71 = Sys Req pressed
Bit 61 = Caps Lock active
Bit 5 1 = Num Lock active
Bit 4 1 = Scroll Lock active
Bit 31 = Right Alt active
Bit 21 = Right Ctrl active
Bit 11 = Left Alt active
Bit 01 = Left Ctrl active
AH Extended shift status:
Bit 71 = Insert active
Bit 61 = Caps Lock active
Bit 51 = Num Lock active
Bit 41 = Scroll Lock active
Bit 31 = Alt pressed
Bit 21 = Ctrl pressed
Bit 11 = Left Shift pressed
Bit 01 = Right Shift pressed
16.6.16 Interrupt 17h–Parallel Printer Services
The INT 17 software interrupt supports up to 4 parallel adapters. The BIOS stores the standard base
addresses for three parallel adapters in the BIOS Data Area at 3FCh, 378h, and 278h. These services
use the I/O ports 0278h-027Ah, 0378h-037Ah, and 03BCh-03BEh.
Interrupt 17h Parallel Printer Services
AH = 00h Print character
Entry:
AL Character to print
DX Printer port (0-3)
Exit:
AH Printer Status (see below)
AH = 01h Initialize printer port
Entry:
DX Printer port (0-3)
Exit:
AH Printer Status (see below)
AH = 02h Return printer status
Entry:
DX Printer port (0-3)
Exit:
AH Printer Status:
Bit 01 = Time-out error
Bit 1Reserved
Bit 2Reserved
Bit 31 = I/O error
Bit 41 = Printer selected
Bit 51 = Out of paper
Bit 61 = Acknowledgment from printer
Bit 71 = Printer not busy