Question

I am trying to print out the offset values.
(Is the term “print” correct? Is there another term for it?

Is the code correct? I am rather confused with documentation for assembly.

print_offsets:  mov  SI,0
                mov  CX,30
                mov  AH,2
                int  21h
                jmp  offsloop

offsloop:       cmp  0,Array[SI]
                ja   print_offset ;if the array element is nonzero
                inc  SI
                dec  CX
                jnz  offsloop

print_offset:   mov DL,SI
                mov  AH,2
                int  21h

Answer 1

If you’re trying to print numbers, your code is incorrect.

INT 21h, AH=2 outputs an ASCII character. What your code is doing is putting the offset value into DL. DOS will treat that offset value as an ASCII character and output that instead.

For example, suppose the first non-zero element is at an offset of 7. Your code will call INT 21h, AH=2 with DL=07. DOS will output the ASCII character 07h which is BEL (basically a system beep). Instead, you would probably want DL=37h in order to output the ASCII character 37h which represents the number 7 digit.

There are a couple of ways of solving this.

The first way is easy – if your Array never has more than 10 elements, you can simply add 30h to the offset to convert the offset value to the correct ASCII character value:

print_offsets:  mov  SI,0          ; SI=offset
                mov  CX,10         ; CX = count (must be <= 10!!!!)

offsloop:       cmp  0,Array[SI]
                ja   print_offset ;if the array element is nonzero
next_element:   inc  SI
                dec  CX
                jnz  offsloop
                jmp finished

print_offset:   mov DL,SI
                add DL, 30h      ; convert offset to ASCII digit 0..9
                mov  AH,2
                ; save the registers in case INT 21h modifies them!
                push cx          ; save current count
                push si          ; save current offset
                int  21h
                pop si           ; restore current offset
                pop cx           ; restore current count
                jmp next_element
finished:
                ; do something else!

The second way is more complex because you need to implement a full integer-to-ascii conversion routine. But there are plenty of code samples out there that can do that.