Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
Setvector
Set Interrupt Vector
Function
Call 25H
Sets a particular interrupt vector. The operating system can
then manage the interrupts on
a per-process basis. This call sets
the address in the vector table for the specified interrupt to the
address
of the interrupt handling routine in AL.
Note that programs should never set interrupt vectors by writing
them directly in the low memory vector table.
Entry Conditions:
AH = 25H
AL
= number of the interrupt to set
DS:DX = address of the interrupt handling routine
Macro Definition:
set-vector macro
push
mov
mov
mov
mov
int
POP
endm
mQV
Example:
Id5 dx,intvector
mov ah,ZSH
mov a1,intnumber
int
21 H
:Therearenoerrors returned
interrupt,seg-addr,off-addr
d5
ax,seg-addr
d5 ,ax
dx,off-addr
a1,interrupt
ah,25H
21 H
d5
77

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200