CODEWITHSUNDEEP
assemblyx86
user3593369
user3593369

Reputation: 3

What code can echo a character in assembly language?

The following code does assemble, build and run successfully but it doesn't do anything so I want it to output a character that's entered from the keyboard and display it to the screen. How can I do this? I've tried different lines of code and looked online but I can't find anything.

I'm still learning asm so any help or advice would be appreciated.

        ;NASM-IDE ASM Assistant Assembler Project File
;BITS 16            ;Set code generation to 16 bit mode
;ORG 0x0100     ;Set code start address to 0100h


SEGMENT .text        ;Main code segment

PUTCH:             
PUSH AX        

MOV AH, 2H
INT 21H

POP AX                 

ret  

GETCH:
PUSH BX

MOV BH, AH 

MOV AH, 08H 
INT 21H    

MOV AH, BH 

POP BX

ret

PUTLINE:
PUSH AX
PUSH BX

MOV AH, 004CH
INT 21H   

POP AX
POP BX

ret

SEGMENT .data       ;Initialised data segment


SEGMENT .bss        ;Uninitialised data segment

Upvotes: 0

Views: 4924

Answers (2)

karen grace victor
karen grace victor

Reputation: 1

mov ah,01

int 21h

;this service accepts a character, echoes it, and stores it into al

Upvotes: 0

Danke Xie
Danke Xie

Reputation: 1797

It looks like you only have 3 procedures: putch, getch and putline. But there is no "main" procedure. That's why you don't see any output.

If you add the following code at the beginning (before "PUTCH:"), you may get it to read a character from keyboard, then echo it to the STDOUT, and then terminates the program.

XOR AX,AX           ; clear AX
call GETCH          ; read a char into AL
call PUTCH          ; print the char from AL
MOV AX, 4C00h       
INT 21h             ; exit with code 0

Upvotes: 1

Related Questions