Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
SetCtrlCTrapping
CONTROL-C Check Function Call 33H
MS-DOS only checks for a CONTROL-C on the controlling
device when performing function call operations 01H-0CH
to that device. Function Call 33H lets you expand this
checking
to include any system call. For example, with the
CONTROL-C trapping
off, all disk I/O proceeds without
interruption. With CONTROL-C trapping on, the CON-
TROL-C interrupt is given
at the system call that initi-
ates the disk operation.
Note that programs using Function Calls 06H
or 07H to
read CONTROL-Cs as data must ensure that the CON-
TROL-C check is off.
Entry Conditions:
AH = 33H
AL
= function
00H = Return current state
OIH
= Set state
OOH
= Off
OIH = On
DL
= switch (if setting state)
Exit Conditions:
DL = current state
OOH = Off
OIH
= On
Error Return:
AL = FFH
The function passed in AL was not in the range 00H-
OIH.
Example:
SetCtrlCTrapping equ 33H
mov dl ,Val
mov a1,func
mow a1,SetCtrlCTrapping
96

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