desperate help!!!

I've been working on this for 12 hours... I dont know why it doesnt work and my instructor hasnt been responding in the past 48hours... someone give me a little hint plz:cry: :cry: :cry:

Code:

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INCLUDE irvine32.inc


.data
charArr BYTE 2 DUP(?)


.code
main PROC
; these just get two character inputs
        call ReadChar
        mov  charArr, al
        call ReadChar
        mov  [charArr+1], al
       
       
        ; push the characters onto the stack
        push OFFSET [charArr + 1]
        push OFFSET charArr
        call swap
       
       
       
        mov  al, charArr
        call WriteChar
        mov  al, [charArr+1]
        call WriteChar
main ENDP



swap PROC
        push ebp
        mov  ebp, esp

       

        mov  al, BYTE PTR [ebp+8]
        mov  bl, BYTE PTR [ebp+12]
        mov          [ebp+8],  bl
        mov          [ebp+12], al
       
       
        pop  ebp
        ret 8       
swap ENDP


END main

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readChar and writeChar are provided in libraries... just read and write chars. uuh it's supposed to swap the two characters stores in the charArr but it doesnt do anything. what's wrong

I don't know what assembler you are using but from what I can tell your program looks fine. Here is one suggestion though:
Perhaps you could use the XCHG (exchange (swap) instruction)?
Also what do you mean it does nothing? Does the pogram hang when executed or does it return the values that it supposed to swap without swapping them?

hehe yeah it would display the result without them being swapped... I wrote this afterwards... after turning it in haha. it works:

Code:

---

INCLUDE irvine32.inc

.data
charArr BYTE 2 DUP(?)

.code
main PROC
        ; Get two character inputs and save them in a 2-byte array
        call ReadChar
        mov  charArr, al
        call ReadChar
        mov  [charArr+1], al
       
       
        ; push the offsets of characters onto the stack
        mov eax, OFFSET charArr +1
        push eax                                        ; second parameter
        dec  eax
        push eax                                        ; first parameter
       
        call swap2
       
       
        mov  al, charArr
        call WriteChar
        mov  al, [charArr+1]
        call WriteChar
       
        exit
main ENDP


swap2 PROC
        push ebp                        ; save EBP
        mov ebp, esp
               
        mov eax, [ebp+8]        ; offset of first parameter
                                                ; EBP+8 is an offset. when dereferenced, it points
                                                ; to the offset of the first array element (yeah, offset of an offset)
                                                ; EAX has now the offset of the first array element
        ;mov al, [eax]                ; this would give the value of the first array element
       
       
        mov bl,        [eax]                ; Value of first parameter
        mov eax, [ebp+12]        ; offset of second parameter
        xchg [eax],bl                ; bl=val of second param. Second param is set to first param.
        mov eax, [ebp+8]        ; offset of first param
        xchg [eax],bl                ; first param is set to second param
       
       
       
       
        pop ebp                                ; restore EBP
        ret 8
swap2 ENDP
END main

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Code:

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        ; push the characters onto the stack
        push OFFSET [charArr + 1]
        push OFFSET charArr
        call swap

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Methinks it was the fact that you should have either not have had brackets or had brackets (this fact changes from assembler to assembler.)