Problems compiling code.

[Zaratustra]

Hi all,

First of all I downloaded the masm32 from http://www.masm32.com/masmdl.htm and it installed successfully in my windows 7 machine. After that I was able to load some examples with the quick editor and running them.

But the thing is that Im trying to learn assembly with the book "Guide to assembly" author James T. Streib, and simply cant  compile the first program example:

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.386
.model flat, c
.stack 100h
.data
num1    sdword ? ; first number
num2    sdword ? ; second number
        .code
main    proc
        mov num1,5 ; initialize num1 with 5
        mov eax,num1 ; load eax with contents of num1
        mov num2,eax ; store eax in num2
        ret
main    endp
        end


The code is converted to .obj, but I get the following error from the linker:

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LINK:error LNK2001: unresolved external symbol _mainCRTStartup


Is there a solution for this? Or is there something Im missing?
I've seen that all the examples in the forum have library declarations, I dont know if it has to do with it.
By the way, the code above is in the bin directory of masm32.
Sorry but Im a total noob in the subject. Thanx.

[dedndave]

it's 16-bit code and a 16-bit book in a win32 world

you can use Link16.exe, rather than Line.exe to link 16-bit programs

better to get a different book
or no book at all - the info you need is available online

[Zaratustra]

Thanx dedndave for your answer.

Well, Im getting more cofused then, how can it be a 16 bit code, when the author claims to teach 32 bit code? Also, he is using extended registrers, thats from the 32 bit world, isn it?

Thanx fro your time.

[dedndave]

sorry about that
we get that mistake so often in here, i didn't look very closely at the code - lol

what seems to be missing is the entry point
also - in win32, flat model - no stack declaration is required
(when i saw stack, i assumed 16-bit code)

Code Select Expand

.386
.model flat, c
.data
num1    sdword ? ; first number
num2    sdword ? ; second number
        .code
main    proc
        mov num1,5 ; initialize num1 with 5
        mov eax,num1 ; load eax with contents of num1
        mov num2,eax ; store eax in num2
        ret
main    endp
        end     main                ;entry point in END statement

[dedndave]

as a side note....

you can use 32-bit registers in 16-bit (DOS) code
what makes it 16 or 32 bit is the segment type
the assembler and linker create addresses of the proper size

of course, the OBJ and EXE files also have different formats

[dedndave]

now that you've had a little time to play with that, try this one...

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include \masm32\include\masm32rt.inc
.data
num1    sdword ? ; first number
num2    sdword ? ; second number
        .code
main    proc
        mov num1,5 ; initialize num1 with 5
        mov eax,num1 ; load eax with contents of num1
        mov num2,eax ; store eax in num2
        print uhex$(num1),13,10
        print uhex$(num2),13,10
        inkey
        exit
main    endp
        end     main

it creates an EXE that you can run in a console window

[Zaratustra]

Wow thanx, my programs now runs fine, and the last example is wonderful.

Well but that is strange, why the print function does not need "invoke"?.

For example the Hellow world program that use stdout needs to use invoke:

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include \masm32\include\masm32rt.inc

.data
HelloWorld db "Hello World!",13,10,0
.code
main proc
invoke StdOut, addr HelloWorld
inkey "Press a key to continue ..."


invoke ExitProcess, 0
main endp
     end main


[MichaelW]

Well but that is strange, why the print function does not need "invoke"?.

Because print is not a function, it's a macro:

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    print MACRO arg1:REQ,varname:VARARG      ;; display zero terminated string
        IFNDEF __UNICODE__
          invoke StdOut,expand_prefix(reparg(arg1))
        ELSE
          invoke StdOutW,expand_prefix(reparg(arg1))
        ENDIF
      IFNB <varname>
        IFNDEF __UNICODE__
          invoke StdOut,chr$(varname)
        ELSE
          invoke StdOutW,chr$(varname)
        ENDIF
      ENDIF
    ENDM


See \masm32\macros\macros.asm, which defines ~120 macros currently.

[dedndave]

sorry - i should have spent a little more time explaining that
i was tired, and went to bed

uhex$ and exit are also macros that may be looked up, as Michael suggested
i learned a lot by looking up the macros and functions to see how they are written
so, besides the macros.asm file that Michael mentioned,
there are also several files in \masm32\m32lib worth looking over

it's great to use them - but even better to understand what's going on underneath

[Gunther]

it's great to use them - but even better to understand what's going on underneath

That's absolutely right. And welcome to the forum, Zaratustra.

Gunther

[Zaratustra]

Thanx for your answers, they are relly helpful.

Thats right, I realize the thing about macros a little bit later, I will continue my quest in learning assembly and of course once I get more confortable with the subject I will take a look at the functions and macros.