Thursday, February 02, 2006
XIP image and Executing from RAM
While building an Windows CE Operating System image for a target, one can specify the image so that it is built for flash. In this case bootloader doesn't copy the OS image to RAM but instead it directly jumps to kernel entry point function in flash. This is possible only if the flash media supports XIP (Execute In Place).
Sometimes it may be necessary to make a particular module A.exe run out of RAM even though the image is built for flash. This can be achieved by marking A.exe to be compressed while building the image. During execution kernel copies a compressed module to RAM, uncompresses it and then it is executed.
This is how the entry for A.exe will be in platform.bib file:
A.exe $(_FLATRELEASEDIR)\A.exe NK SC
Here SC specifies the A.exe is a Compressed, System file.
Sometimes it may be necessary to make a particular module A.exe run out of RAM even though the image is built for flash. This can be achieved by marking A.exe to be compressed while building the image. During execution kernel copies a compressed module to RAM, uncompresses it and then it is executed.
This is how the entry for A.exe will be in platform.bib file:
A.exe $(_FLATRELEASEDIR)\A.exe NK SC
Here SC specifies the A.exe is a Compressed, System file.
