Re: opening and reading a character from a file with emu8086 assembler

In previous example there should be:

JNE print ;repeat if not end of the buffer (instead of file).

and

mov al, buf ; char is in BUF... (and AL).

and the size of the buffer can be increased up to about 50k.

Here is a more general solution to open files of any length.

; ==========================================

; emu8086 version 4.00-Beta-12 or better is required!
; put file named "input.txt" to c:\emu8086\vdrive\c\
; (it's possible to copy "ReadMe.txt" and rename it or use any other
file that contains ASCII chars).

org 100h ; .com memory layout

mov dx, offset file ; address of file to dx
mov al,0 ; open file (read-only)
mov ah,3dh
int 21h ; call the interupt
jc terminate ; if error occurs, terminate program
mov bx,ax ; put handler to file in bx

mov cx,1 ; read one character at a time
print:
lea dx, BUF
mov ah,3fh ; read from the opened file (its handler in bx)
int 21h
CMP AX, 0 ; how many bytes transfered?
JZ terminate ; end program if end of file is reached (no bytes
left).
mov al, BUF ; char is in BUF, send to ax for printing (char is
in al)
mov ah,0eh ; print character (teletype).
int 10h
jmp print ; repeat if not end of file.


terminate:
mov ah, 0 ; wait for any key...
int 16h
ret

file db "c:\input.txt", 0
BUF db ?


END




; ==========================================

If you have any other questions feel free to e-mail:
pnp[at]emu8086[dot]com

.

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