Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
C onInput Status
Check Keyboard Status Function Call OBH
Checks to see if a character is available in the type-
ahead buffer. If CONTROL-C is in the buffer, Interrupt
23H is executed.
Entry Conditions:
AH = 0BH
Exit Conditions:
If AL = FFH, there are characters in the type-ahead
buffer.
If
AL = 00H, there are no characters in the type-ahead
buffer.
Macro Definition:
check-kbd-5tatu5 macro
mov ah, 0BH
int 21 H
endm
Example:
The following program continuously displays the time until
any key is pressed.
time db "00: 00: 00. EO", 13,l 0 ,"$'I
ten db 10
f unc-0BH: get-time
convert ch,ten, time
convert cl,ten, time[31
convert dh,ten, tlme[61
convert dl,ten, time[91
display time
check-kbd-status
cmp a1,OFFH
le all-done
Imp func-OBH
all-done: ret
;5ee Function 2CH
;see end of chapter
;see end of chapter
;5ee end of chapter
;5ee end of chapter
;see Function 09H
;THIS FUNCTION
;ha5 a key been typed?
;yes, go home
;no, keep displaying
; t ime
45

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