get useriput

[xellos]

how can i get input from the user?
i looked on this site http://spike.scu.edu.au/~barry/interrupts.html
it says you can use AH 06 console input/output

but there is no tut on how to do that.
can someone help me out?

[dedndave]

i suggest you download Ralf Brown's Interrupt List
http://www.cs.cmu.edu/~ralf/files.html

[xellos]

i dont understand all that im just starting asm

[dedndave]

well, it is a useful reference
get it and browse through the functions you already know and understand
that will help you read other functions

as for INT 21h, function 6, i think it requires a data structure

oh - it is for single character input

        mov     ah, 6
        mov     dl, 255
        int     21h

if there is a character, it is returned in AL and removed from the keyboard buffer
if there is no character, the ZF is set (i.e. ZERO = true)

[FORTRANS]

Hi,

   MS-DOS function 1 is "Read Keyboard with Echo".
Waits for a keypress if none available, single character.

Code Select Expand


        MOV     AH,1
        INT     21H
        MOV     [InputChar],AL


   Function 6 is "Direct Console I/O".   For input, it
is a deadndave says, looks for a char, but does not
wait.

Code Select Expand


        MOV     DL,0FFH ; Indicate input wanted
        MOV     AH,6
        INT     21H
        JZ      NoCharYet
        MOV     [InputChar],AL


   Function 7 is "Direct Console Input".  It waits for a
character but does not echo it to the screen..  It also
does not check for a Ctrl-C.

Code Select Expand


        MOV     AH,7
        INT     21H
        MOV     [InputChar],AL


   Function 8 is "Read Keyboard Without Echo".  This is
Like fn 7 except for Ctrl-C checking.

   Function 0AH is "Buffered Keyboard Input".  It will get
an entire string, but rquires an input buffer structure.
See the thread "Buffered Input.[solved]", and reuse it if
you still have questions.

http://www.masm32.com/board/index.php?topic=10689.0

HTH,

Steve N.

[xellos]

i have managed to make this but whats wrong?

Code Select Expand


.model small
.stack 100h
.data

    string db 20,0,21 dup('$')

.code

start: 

    mov dx, offset string
    mov ah, 0ah
    int 21h

    mov dx, offset string
    mov ah, 09h
    int 21h
   
    mov ah, 4ch             ; exit program.
    int 21h   

end start

i can type something but when i hit enter instead of printing the text i typed it prints a mess of chars.

[dedndave]

try this...

        mov dx, offset string
        mov ah, 0ah
        int 21h

        mov dx, offset string+2
        mov ah, 09h
        int 21h

[dedndave]

actually, the data should look like this...

Code Select Expand

BufLen  db 20
RetLen  db 0
BufInp  db 21 dup(?)

then, in the code, terminate the string...

Code Select Expand

        mov     dx,offset BufLen
        mov     ah,0Ah
        int     21h

        xor     bx,bx
        mov     bl,RetLen
        mov byte ptr BufInp[bx],24h     ;'$'

        mov     dx,offset BufInp
        mov     ah,9
        int     21h

that way, when you go to use the buffer a second time, it gets properly terminated

[FORTRANS]

Hi,

   It looks as if you need to initialize your data segment register DS.
On startup it points to the PSP, not your data.

Steve

[dedndave]

what Steve said - lol
oh yah - that would also help