Commodore Amiga A500 Technical Reference Manual page 136

TIMER DEVICE
SERVICE ROUTINE -
INT 1Ah
READ CLOCK (AH
=
OOh)
INPUT: DS
=
ROM data segment (0040h)
OUTPUT: A L
=
24-Hour Rollover flag
CX
=
High word of Clock Count
D X
=
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 1 B h
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 t o point t o 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
t o OFFh.