Question

I’m new to writing assembly code and I’m having trouble printing out the values of my array using a loop. The code I have prints out the value of the counter and the not the values in the array, can someone please explain what I’m doing wrong, also how do I point to the top of the array? I have tried using different registers, but nothing seems to be working. My professor asks that I do it this way (if it seems inefficient):

           .386
           .model flat
ExitProcess PROTO NEAR32 stdcall, dwExitCode:dword
Include io.h
cr         equ 0DH
Lf         equ 0AH
           .stack 4096
           .data
newline    byte CR, LF, 0
whitespace byte 32,32,0     
arr        dword 10 dup(?)
n          dword 2
string     byte  40 dup(?)
prompt     byte "Please enter a value: ", 0
origArr    byte "Original Array", 0
           .code
_start:
           mov    ecx,n         ; number of values in the array
           lea    ebx,arr       ; address of the array
           sub    edi, edi
top:       cmp    ecx, 0
           je     done
           output prompt
           input  string, 40
           atod   string
           mov    [arr+edi], ecx
           add    edi, 4
           loop   top
done:      output origArr
           mov    ecx, n
           call   myproc

         INVOKE ExitProcess, 0

PUBLIC  _start
myproc proc near32
       .data
val_str byte 11 dup(?), 0
       .code
        push eax
        push edi 
        push ecx
        sub edi,edi              ; index register
top2:   mov eax, [ebx+edi]
        dtoa val_str, eax
        output val_str
        add edi,4                ; modify esi rather than ebx
        loop top2
        pop ecx 
        pop edi
        pop eax
        ret
myproc endp

         END    

Any suggestions are appreciated.

Answer 1

mov    [arr+edi], ecx

You’re storing the loop counter, rather than the return value of atod.