9.2 Preprocess/Trim
Preprocessing is an intrinsic behavior of C compiler and will be always done automatically without explicitly calling. A separate preprocessing step is needed by those non-C files which have no preprocessing supported in their compiler or assembler.
For example, in order to use macros defined in C header files, #include
directives can be used in an assembly file. A separated preprocessing step will
be used to complete macro replacement before calling assembler. The .VFR files,
.asl files and .dxs files also need preprocessing step to allow using macros in
them.
In addition, the preprocessed assembly files, VFR files and .dxs files need an additional Trim step to remove unnecessary contents left by preprocessor.