Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
AuxOutput
Auxiliary Output Function Call 04H
Outputs a character to the auxiliary device. No status or
error code is returned.
If CONTROL-C is typed at console input, Interrupt 23H is
executed.
Entry Conditions:
AH = 04H
DL = character to output
Macro Definition:
aux-output macro character
mov d1,character
mov ah,04H
int 21 H
endm
Example:
The following program gets a maximum of 80 bytes from
the keyboard, sending each to the auxiliary device. It
stops when
a null string (CR only) is typed.
string db 81 dup(7) ;see Function 0AH
func-04H: get-string 80,string
cmp string[lI,E
]e continue
mov cx, word ptr string[ll
mov bx,0
sent-it: aux-output string[bx+El
inc bx
loop send-it
imp func-04H
continue:
;see Function 0AH
;null string?
;yes, all done
;get string length
;set index to 0
;THIS FUNCTION
;bump index
;send another character
;get another string
36

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