RTEMS CPU Architecture Supplement
Each processor family supported by RTEMS has a list of features which vary between CPU models within a family. For example, the most common model dependent feature regardless of CPU family is the presence or absence of a floating point unit or coprocessor. When defining the list of features present on a particular CPU model, one simply notes that floating point hardware is or is not present and defines a single constant appropriately. Conditional compilation is utilized to include the appropriate source code for this CPU model's feature set. It is important to note that this means that RTEMS is thus compiled using the appropriate feature set and compilation flags optimal for this CPU model used. The alternative would be to generate a binary which would execute on all family members using only the features which were always present.
This section presents the set of features which vary across PowerPC implementations and are of importance to RTEMS. The set of CPU model feature macros are defined in the file cpukit/score/cpu/ppc/ppc.h based upon the particular CPU model defined on the compilation command line.
RTEMS CPU Architecture Supplement
Copyright © 1988-2004 OAR Corporation