Coding with Assembler problem

[xTripper]

Hello, I've started to program in Assembler and I got this task to tell the number of all upper case letters. I've got this code, but when I try to compile it an error pops out. Do you know where the problem could be?

CODE

Spoiler

.model small

.stack 100h

.data

type db "Your text: "
enter db 10, 13, "$"
bufer db 255
read db ?
result db "Result: $"
number db 0

.code

start:

mov ax, @data
mov ds, ax

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

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

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

mov cl, read
mov bx, offset bufer
mov dl, 'A'
mov dh, 'Z'

ciklas:

CMP [ds:bx], dl
JBE not
CPM [ds:bx], dh
JAE not
INC skaicius

not:
INC bx

DEC cl
CMP cl, 0
JNE ciklas

MOV byte ptr [ds:bx], '$'

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

mov ah, 4Ch
mov al, 0
int 21h

END start

Any tips?

 

[rgd1101]

what the error? try reading what the error mean?

 

[xTripper]

Right, I forgot. The error is "Illegal instruction" but I still don't know what kind of illegal instruction it is...

 

[rgd1101]

find out which line and then read up on why it is illegal instruction

 

[xTripper]

The problem is I don't know which line. Compilator doesn't give my any hints, that's why I'm asking on this forum

 

[Alabalcho]

What OS you are doing that on?
What is the name and version of the compiler / assembler?
Is this an error in your code, or the compiler itself gave you "Invalid instruction at address xxxxxx"?

 

[itmoba]

(1) Given the simplicity of the program and the first interrupt (21h), it's clear that it's for DOS.

(2) The assembler being used seems to be MASM.

Solution: Not doing your homework, sorry.

 

[Alabalcho]

(1) Given the simplicity of the program and the first interrupt (21h), it's clear that it's for DOS.
(2) The assembler being used seems to be MASM.
Solution: Not doing your homework, sorry.

Could it that OP is trying original 16-bit MASM.EXE, on 64-bit Windows?

 

[rgd1101]

look like is possible
http/answers.microsoft.com/en-us/windows/forum/windows_7-windows_programs/how-to-run-masmexe-dos-program-on/231a3dcc-feea-4952-97d3-e62c45c86c7e

 

[itmoba]

(1) Given the simplicity of the program and the first interrupt (21h), it's clear that it's for DOS.
(2) The assembler being used seems to be MASM.
Solution: Not doing your homework, sorry.

Could it that OP is trying original 16-bit MASM.EXE, on 64-bit Windows?

Anything is possible. It could be that they're mixing syntax, but it's just as easy to say that they should be using DOSBox or Bochs -- of course, it'll require a proper license for MS-DOS.