User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 179
16.6.10 Interrupt 15h–System Services
The INT 15 software interrupt handles a variety of system services:
• Multi-tasking–80h, 81h, 82h, 85h, 90h, and 91h
• Joystick support–84h
• Wait routines–83h and 86h
• Protected-mode support–87h and 89h
• Report extended memory to 64 kB–88h
• System information–C0h
• Advanced Power Management (optional)–53h
• Report extended memory above 64 kB (optional)–8Ah and E8h
• PS/2 Mouse support (optional)–C2h
• EISA Support (optional)–D8h
The first section describes the standard Interrupt 15 services, followed by separate sections de-
scribing each of the optional services.
Interrupt 15h System Services
AH = 00-03h Cassette services
Entry:
No longer supported
Exit:
Carry 1 = Not supported
AH = 80h Device open
Entry:
BX Device identifier
CX Process identifier
AH = 81h Device close
Entry:
BX Device identifier
CX Process identifier
AH = 82h Program termination
Entry:
BX Device identifier
AH = 83h Event wait
AL 00 = Set interval
Entry:
ES:BX Pointer to byte in caller's memory that will have
bit 7 set when interval expires.
CX Microseconds before post (high byte)
DX Microseconds before post (low byte)
Exit:
AH 83h
AL A value written to CMOS register B
00h = Function busy
AL 01 = Cancel set interval
Exit:
AH 83
AL 00
AH = 84h Joystick support
Entry:
DL 00 = Read switch settings
Exit:
AL Switch settings
DL 01 Return resistive inputs
Exit:
AX Input bit 0 (Joystick A, x coordinate)
BX Input bit 1 (Joystick A, y coordinate)
CX Input bit 2 (Joystick B, x coordinate)
DX Input bit 3 (Joystick B, y coordinate)