8086 Assembly Programing problem

[Lord Loh.]

I have written a small 8086 programme to display a string on the PC screen using MS DOS interrupts....

I would like to have my string "Hello World !" stored in the data segment...

My assembler a86/nasm demands the datasegment to be defined before the code segment...

The code is generated and when I see the .com file, the string is defined before the code.... And in DEBUG Utility, the string is placed at cs:0100 and the dat a is executed before the code.... I guess that the programming is giving the desired output only by fluke...

Please help....

.DATA SEGMENT

hm:
 db 'Hello World'
.DATA ENDS

.CODE SEGMENT
mov ax,SEG hm
mov ds,ax
mov si,OFFSET hm
mov cx,0005h
mov ah,02h
writestring:
mov dl,[si]
int 21h
inc si
loop writestring
int 20h
.CODE ENDS

Debug Output

D:\a86>debug 1.com
-d
0B5B:0100  48 65 6C 6C 6F 20 57 6F-72 6C 64 8C C8 8E D8 BE   Hello World.....
0B5B:0110  00 01 B9 05 00 B4 02 8A-14 CD 21 46 E2 F9 CD 20   ..........!F...
0B5B:0120  75 06 C7 06 7E 01 FF FF-39 3E 80 01 75 05 6A 00   u...~...9>..u.j.
0B5B:0130  E8 0F 12 6B DF 0E 8B B7-2E 4B C1 E6 02 03 36 B4   ...k.....K....6.
0B5B:0140  52 EB 18 8B C6 2B 06 B4-52 C1 F8 02 50 E8 66 A1   R....+..R...P.f.
0B5B:0150  8B 04 C1 E0 02 03 06 B4-52 8B F0 83 3C FF 75 E3   ........R...<.u.
0B5B:0160  6B DF 0E C7 87 2E 4B FF-FF 33 C0 5E 5F C9 C2 02   k.....K..3.^_...
0B5B:0170  00 00 55 8B EC 56 8B 5E-04 6B DB 0E 8D 87 2E 4B   ..U..V.^.k.....K

Unassembled

-u
0B5B:0100 48            DEC     AX
0B5B:0101 65            DB      65
0B5B:0102 6C            DB      6C
0B5B:0103 6C            DB      6C
0B5B:0104 6F            DB      6F
0B5B:0105 20576F        AND     [BX+6F],DL
0B5B:0108 726C          JB      0176
0B5B:010A 64            DB      64
0B5B:010B 8CC8          MOV     AX,CS
0B5B:010D 8ED8          MOV     DS,AX
0B5B:010F BE0001        MOV     SI,0100
0B5B:0112 B90500        MOV     CX,0005
0B5B:0115 B402          MOV     AH,02
0B5B:0117 8A14          MOV     DL,[SI]
0B5B:0119 CD21          INT     21
0B5B:011B 46            INC     SI
0B5B:011C E2F9          LOOP    0117
0B5B:011E CD20          INT     20

 

[JASMINE DOSHI]

hi dear plz reffer book name MAZIDI & MAZIDI u get direct coading of this program i have done it.

 

[Lord Loh.]

I guess the Mohd. Ali Mazadi Book is for 8051... I checked google for "Mazadi 8086" and there are no relavent results....

 

[purko]

Small rewriting

.MODEL SMALL
.STACK
.DATA
hm  label near 
    db 'Hello World'
hm_size = $ - hm  
.CODE 
start:
    mov ax, SEG hm 
    mov ds,ax 
    mov si,OFFSET hm 
    mov cx, hm_size
    mov ah,02h 
writestring: 
    mov dl,[si] 
    int 21h 
    inc si 
    loop writestring 
    int 20h 
end start