Commodore Amiga A500 - Page 136

TIMER DEVICE
SERVICE ROUTINE
-
INT 1Ah
READ CLOCK (AH = OOh)
INPUT: DS = ROM data segment (0040h)
OUTPUT: AL = 24-Hour Rollover flag
CX
= High word of Clock Count
DX
= Low word of Clock Count
SET CLOCK (AH = 01 h)
INPUT: DS = ROM data segment (0040h)
CX = High word of Clock Count
DX = Low word of Clock Count
OUTPUT: AH
= 0
USER SUPPLIED KEYBOARD BREAK ROUTINE - INT 1Bh
When a CTRL + ScrLock is detected, this INT is issued. A USER Break
Routine may be invoked here. Note that this function is used by
MSDOS.
USER SUPPLIED TIMER INTERVAL TICK - INT 1Ch
This interrupt is called internally after each timer interrupt (18.2
Hz).
It is initialized to point to a dummy 1 RET instruction.
CRT CONTROLLER PARAMETERS - DWORD POINTER AT INT
IDH VECTOR
Default Video CRT Parameter Block
DEFAULT DISK PARAMETER BLOCK - DWORD POINTER AT
INT 1 EH VECTOR
Default Diskette Parameter Block
EXTENDED GRAPHIC CHARACTER SET - DWORD POINTER AT
INT
1 FH VECTOR
Character Generator ROM used in Graphic mode for characters 80H
to
OFFh.