IBM 5150 Hardware Reference Manual

MOV AH,l ;function is to set time of
day.
MOV
CX,HIGH_COUNT ;establish the current time.
MOV
DX, Low_COUNT
INT
lAH ;Set the time.
~ While to read the time of day:
MOV
AH,O ;function is to read the time
of day.
INT lAH
;read the timer.
As a general rule, the BIOS routines preserve all registers except
for
AX and the flags. Other registers are modified on return
only if they are returning a value to the caller. The exact register
usage can be seen in the prologue
of each BIOS function.
Interrupt Vector Listing
Interrullt Number
Name
BIOS Initialization
0
Divide by Zero
None
1
Single Step
None
2
Non Maskable
NMLlNT (FOOO:E2C3)
3
Breakpoint
None
4
Overflow
None
5
Print
Screen PRINLSCREEN (FOOO:FF54)
6
Unused
7
Unused
8
Time of Day TIMER-INT (FOOO:FEA5)
9
Keyboard
KLINT (FOOO:E987)
A
Unused
8259
B
Unused
Interrupt
C
Unused (Reserved Communications)
Vectors
D
Unused
E
Diskette DISK_I NT (FOOO:EF57)
F
Unused (Reserved Printer)
10
Video
VIDEO_I 0 (FOOO:F065)
11
Equipment Check
EQUIPMENT (FOOO:F84D)
12
Memory
MEMORY_SIZE_DETERMINE (FOOO:F841)
13
Diskette
DISKETTE_I 0 (FOOO:EC59)
14
BIOS Communications RS2.3LI 0 (FOOO:E739)
15
Entry Cassette CASSETTE_I 0 (FOOO:F859)
16
Points Keyboard KEYBOARD_I 0 (FOOO:E82E)
17
Printer PRINTER_I 0 (FOOO:EF02)
18
Cassette BASI C (F600:0000)
19
Bootstrap BOOLSTRAP (FOOO:E6F2)
lA Time of Day
TIME_OF_DAY (FOOO:FE6E)
lB User Supplied Keyboard Break DUMMY_RETURN (FOOO:FF53)
lC Routines
Timer T\ick ,
DUMMY
RETU RN (FOOO: FF53)
lD Video Initialization VIDEO_PARMS (FOOO:FOA4)
BIOS
IE Diskette Parameters DISK_BASE (FOOO:EFC7)
Parameters
IF Video Graphics Chars
None
3-3

IBM 5150 Specifications

General

Processor	Intel 8088
Clock Speed	4.77 MHz
RAM	16 KB - 256 KB
Manufacturer	IBM
Model	5150
Release Year	1981
Storage	5.25-inch floppy drives
Graphics	MDA or CGA
Operating System	IBM PC DOS
Ports	Cassette, keyboard
Expansion Slots	5