BSP and Device Driver Development Guide
The file bsp_specs defines the start files and libraries
that are always used with this BSP. The format of this file
is admittedly cryptic and this document will make no attempt
to explain it completely. Below is the bsp_specs
file from the PowerPC psim BSP:
%rename cpp old_cpp
%rename lib old_lib
%rename endfile old_endfile
%rename startfile old_startfile
%rename link old_link
*cpp:
%(old_cpp) %{qrtems: -D__embedded__} -Asystem(embedded)
*lib:
%{!qrtems: %(old_lib)} %{qrtems: --start-group \
%{!qrtems_debug: -lrtemsall} %{qrtems_debug: -lrtemsall_g} \
-lc -lgcc --end-group ecrtn%O%s \
%{!qnolinkcmds: -T linkcmds%s}}
*startfile:
%{!qrtems: %(old_startfile)} %{qrtems: ecrti%O%s \
%{!qrtems_debug: startsim.o%s} \
%{qrtems_debug: startsim_g.o%s}}
*link:
%{!qrtems: %(old_link)} %{qrtems: -Qy -dp -Bstatic \
-T linkcmds%s -e _start -u __vectors}
The first section of this file renames the built-in definition of
some specification variables so they can be augmented without
embedded their original definition. The subsequent sections
specify what behavior is expected when the -qrtems or
-qrtems_debug option is specified.
The *cpp definition specifies that when -qrtems
is specified, predefine the preprocessor symbol __embedded__.
The *lib section insures that the RTEMS library, BSP specific
linker script, gcc support library, and the EABI specific ecrtn
file are used.
The *startfile section specifies that the BSP specific file
startsim.o will be used instead of crt0.o. In addition,
the EABI specific file ecrti.o will be linked in with the
executable.
The *link section specifies the arguments that will be passed to
the linker.
The format of this file is specific to the GNU Compiler Suite. The
argument used to override and extend the compiler built-in specifications
is relatively new to the toolset. The -specs option is present
in all egcs distributions and gcc distributions starting
with version 2.8.0.
BSP and Device Driver Development Guide
Copyright © 1988-2004 OAR Corporation