Technical Document #43

WinDriver supports driver development for the following 64-bit architectures:

• Windows AMD64 or Intel EM64T (x64)
• Linux AMD64 or Intel EM64T (x86_64)

By default, applications created using the 64-bit versions of WinDriver are 64-bit applications. Such applications are more efficient than 32-bit applications. However, you can also use the 64-bit versions of WinDriver to create 32-bit applications that will run on the supported 64-bit platforms. This document outlines two methods for creating such applications:

• Developing a 32-bit WinDriver Application for 64-bit Platforms
• Developing a 32-bit Application for Both 32-bit and 64-bit Platforms

Developing a 32-bit WinDriver Application for 64-bit Platforms

To create a 32-bit WinDriver application for 64-bit platforms, using a 64-bit WinDriver installation, do the following:

1. Create a WinDriver application, as outlined in the WinDriver User's Manual — for example, by generating code with DriverWizard, or using one of the WinDriver samples.


2. Build the application with an appropriate 32-bit compiler for your target operating system, using the following configuration:
   
   
   • Add the KERNEL_64BIT preprocessor definition.
     NOTE
     In the makefiles, the definition is added using the -D flag: -DKERNEL_64BIT.
     
     The sample and wizard-generated Linux makefiles and Windows MS Visual Studio projects, in the 64-bit WinDriver toolkit, already add this definition.
   
   
   • Link the application with the specific version of the WinDriver API library/shared object for 32-bit applications executed on 64-bit platforms — <WD64>\lib\amd64\x86\wdapi<ver>.lib on Windows (e.g., C:\WinDriver64\lib\amd64\x86\wdapi1040.lib) / <WD64>/lib/libwdapi<ver>_32.so on Linux (e.g., /c/WinDriver64/lib/libwdapi1040_32.so).

     On Linux, the installation of the 64-bit WinDriver toolkit on the development machine creates a libwdapi<ver>.so symbolic link in the /usr/lib directory — which links to <WD64>/lib/libwdapi<ver>_32.so — and in the /usr/lib64 directory — which links to <WD64>/lib/libwdapi<ver>_32.so (the 64-bit version of this shared object).
     The sample and wizard-generated WinDriver makefiles rely on these symbolic links to link with the appropriate shared object, depending on whether the code is compiled using a 32-bit or 64-bit compiler.
     

     On Windows, the sample and wizard-generated MS Visual Studio projects are defined to link with wdapi<ver>.lib (see the AdditionalDependencies), but the linker library path refers to the 64-bit library file in the <WD64>\lib\amd64 directory (see AdditionalLibraryDirectories); when using such a project to compile a 32-bit application for 64-bit platforms, add \x86 to the library path in order to link the code with <WD64>\lib\amd64\x86\wdapi<ver>.lib.

Developing a 32-bit Application for Both 32-bit and 64-bit Platforms

If you have both 64-bit and 32-bit WinDriver installations, you can also create a single 32-bit application that can be executed on both 32-bit and 64-bit platforms. This can be done using the following method:

1. Create a DLL (on Windows) or a shared object (on Linux) that concentrates the calls to the WinDriver APIs.
   If you created a WinDriver application using the generated DriverWizard code or one of the WinDriver samples, convert this application to a DLL/shared object.
2. Compile two versions of your DLL/shared object:
   
   • A version for 32-bit platforms: This version should be compiled using a 32-bit compiler, without the KERNEL_64BIT definition, and using the standard 32-bit WinDriver API library/shared object from the 32-bit WinDriver installation — <WD32>\lib\x86\wdapi<ver>.lib on Windows (e.g., C:\WinDriver\lib\x86\wdapi1040.lib) / <WD32>/lib/libwdapi<ver>.so on Linux (e.g., /c/WinDriver/lib/libwdapi1040.so).
   • A version for 64-bit platforms: This version should be compiled with a 64-bit compiler, using the standard 64-bit WinDriver API library/shared object from the 64-bit WinDriver installation — <WD64>\lib\amd64\wdapi<ver>.lib on Windows (e.g., C:\WinDriver64\lib\x86\wdapi1040.lib) / <WD64>/lib/libwdapi<ver>.so on Linux (e.g., /c/WinDriver64/lib/libwdapi1040.so).
3. Write a 32-bit application that communicates with WinDriver via the DLL/shared object that you created; the application should be implemented to load the relevant version of the DLL/shared object — 32-bit or 64-bit — depending on the platform on which it is run.
   Note: This application should be compiled using an appropriate 32-bit compiler, without the KERNEL_64BIT definition.