Question

Can some one tell me how I can use these functions?
int 21h , 4eh , 4fh (in MS Dos )

I wanna list files and directories … how should I do that?

I wish some one could give me a source code or an example of int21h 4eh/4fh ..

Thanks in advance

Answer 1

Hmm…now here’s some ancient code:

.model small, c

.stack

.data
    file_spec db "*.*", 0
    DTA db 128h dup(0)

.code
main proc
    mov ax, @Data
    mov ds, ax
    mov dx,offset DTA
    mov ah,1Ah
    int 21h

    mov dx,offset file_spec
    xor cx, cx
    mov ah,4Eh
    int 21h
    jc  quit

print_name:
    lea si, DTA + 1eh
next_char:
    lodsb
    int 29h
    test al, al
    jnz next_char

    mov al, 13
    int 29h
    mov al, 10
    int 29h

    mov dx, offset file_spec
    xor cx, cx
    mov ah, 4fh
    int 21h
    jnc print_name
quit:   
    mov ax, 4c00h
    int 21h
main endp
    end main

As you can see, in my younger days, I really believed in lots of comments (though, I have to admit that even looking at it now, it doesn’t seem particularly difficult to follow).