PEDasm : example of use

PEDasm : example

adding currency conversion buttons to the window calculator

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Step 1 : Disassembling and recompiling calc.exe

type in a term window :

c:\> calc95st1.bat

this should procuce the following files :

calc.asm , dlImport.inc , kernel32.def , gdi32.def , user32.def , shell32.def

def files must be processed by a librarian editor : lib or link

lib -machine:I386 /out:kernel32.lib /def:kernel32.def ...

compile and link ( source and makefile are downloadable below ).

rq :

PEDasm is launched with an additional config file which correct some generated garbadge code .

download zip source step 1

Step 2 : Adding code to the executable

As an exemple of code reuse I added to and from euro currency button converter to the calculator. These appears only in scientific mode since there is not enough space in normal mode.

After a debugging session ( using /Zi option ) I found that the symbol Data40c008 stood for the main buffer in real8 format. After tracing into the main window proc I also found that Label401a0c was for command processing.

By the way , if you look at the disassembly and the resource file , you will find no button at all. The buttons are not standard windows but custom drawing according to the mouse pointer coordonnates. Imagine : a window manager inside a window manager wich hold only about ten KByte instead of MByte ! Probabely the programmer tried to get around a 64k limitation of an old windows version, and the code still here now.

Modifications tagged with the comment <--modif step2--> consist in adding a constant cteEuroToLocal for french franc to euro parity and several line of code in the window proc to handle buttons pressing. I used the real window manager for that. I also added code to hide these button in normal mode .

download zip source step 2

Screen shot modified calc :