Support ARMv7 instruction set in Windows Embedded Compact applications
- by Valter Minute
On of the most interesting new features of Windows Embedded Compact 7 is support for the ARMv5, ARMv6 and ARMv7 instruction sets instead of the ARMv4 “generic” support provided by the previous releases. This means that code build for Windows Embedded Compact 7 can leverage features (like the FPU unit for ARMv6 and v7) and instructions of the recent ARM cores and improve their performances. Those improvements are noticeable in graphics, floating point calculation and data processing. The ARMv7 instruction set is supported by the latest Cortex-A8, A9 and A15 processor families. Those processor are currently used in tablets, smartphones, in-car navigation systems and provide a great amount of processing power and a low amount of electric power making them very interesting for portable device but also for any kind of device that requires a rich user interface, processing power, connectivity and has to keep its power consumption low. The bad news is that the compiler provided with Visual Studio 2008 does not provide support for ARMv7, building native applications using just the ARMv4 instruction set. Porting a Visual Studio “Smart Device” native C/C++ project to Platform Builder is not easy and you’ll lack many of the features that the VS2008 application development environment provides. You’ll also need access to the BSP and OSDesign configuration for your device to be able to build and debug your application inside Platform Builder and this may prevent independent software vendors from using the new compiler to improve their applications performances. Adeneo Embedded now provides a whitepaper and a Visual Studio plug-in that allows usage of the new ARMv7 enabled compiler to build applications inside Visual Studio 2008. I worked on the whitepaper and the tools, with the help of my colleagues and now the results can be downloaded from Adeneo Embedded’s website: http://www.adeneo-embedded.com/OS-Technologies/Windows-Embedded (Click on the “WEC7 ARMv7 Whitepaper tab to access the download links, free registration required) A very basic benchmark showed a very good performance improvement in integer and floating-point operations. Obviously your mileage may vary and we can’t promise the same amount of improvement on any application, but with a small effort on your side (even smaller if you use the plug-in) you can try on your own application. ARMv7 support is provided using Platform Builder’s compiler and VS2008 application debugger is not able to debut ARMv7 code, so you may need to put in place some workaround like keeping ARMv4 code for debugging etc.
