Introduction
============

This repository contains RTEMS scaffolds that cover the development workflows
required for ESA projects. The Makefiles and the example sources demonstrate
how to:

* support both debug and release compilations
* support compilation for native and emulated FPU usage

Application sources
-------------------
The sources of your project must be set inside the Makefile, in the FPU_SRC and
NONFPU_SRC variables. The VPATH can be used to automatically locate them in 
your source tree:

    VPATH=src:Library/foo:Library/bar:...

    NONFPU_SRC=          \
    	init.c           \
    	tasking.c        \
        ...
    
    FPU_SRC=             \
    	gnc.c            \
    	compute_pi.c
    
As their names suggest, you add a file in the FPU_SRC list
if you want it to be compiled for native FPU use (i.e. without `-msoft-float`).
Whether native or emulated FPU compilation is performed on it, is selected during 
build time ; by the FPU=1 Makefile parameter (see below)

You can control 3 orthogonal options:

## Debug/Release mode:

Use the `CFG` Makefile parameter:

    $ make CFG=debug
    ...
    $ ls -l bin.debug/
    -rwxr-xr-x 1 user user 645273 Mar 16 17:43 fputest

    $ make CFG=release
    ...
    $ ls -l bin.release/
    -rwxr-xr-x 1 root root  47860 Mar 16 17:48 fputest
    -rwxr-xr-x 1 root root 585178 Mar 16 17:48 fputest.debug

If no `CFG` option is passed, the default is Debug compilation.

Notice that in release compilation, the process creates a small binary (containing
only the executable code) and separately, the debug information - for loading
from inside GDB via the `file` command.

## Native FPU usage for the FPU_SRC sources:

To use native FPU compilation for the FPU_SRC list of source files, use the `FPU` Makefile parameter:

    $ make CFG=release FPU=1

To use emulation (default, if `FPU` option is not passed) pass 0:

    $ make CFG=release FPU=0

or just

    $ make CFG=release

## Verbosity:

Compilation messages follow the semantics of the Linux kernel compilations,
emitting short messages by default (CC for compilation, LD for linking):

    $ touch src/task1.c
    $ make
    [CC] objs.debug/FPU_task1.o
    [LD] bin.debug/fputest

If you want to see the complete commands used, invoke `make` with V=1:

    $ touch src/task1.c
    $ make V=1
    sparc-rtems4.8-gcc -c -B/home/user/development/rtems/sparc-rtems4.8/leon3/lib \
        -specs bsp_specs -qrtems -nodefaultlibs -mcpu=cypress -DBSP_leon3  -g -Wall \
        -D_DEBUG -I/home/user/development/build/rtems-impr/testsuites/support/include \
        -I src -msoft-float -o objs.debug/FPU_task1.o src/task1.c
    sparc-rtems4.8-gcc -g -o bin.debug/fputest objs.debug/NONFPU_init.o \
        objs.debug/NONFPU_printk.o objs.debug/NONFPU_leon3.o objs.debug/FPU_task1.o \
        -msoft-float -B/home/user/development/rtems/sparc-rtems4.8/leon3/lib \
        -specs bsp_specs -qrtems -nodefaultlibs -mcpu=cypress -DBSP_leon3  \
        -nodefaultlibs -Wl,--wrap,_IO_Initialize_all_drivers \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_event.a \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_msg.a \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_sem.a \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_timer.a \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_rtmon.a \
        /home/user/development/rtems/sparc-rtems4.8/leon3/lib/libno_ext.a \
        -Wl,--start-group -lrtemscpu -lio -lno_event -lno_msg -lno_sem -lno_timer \
        -lno_rtmon -lno_ext -lrtemsbsp -llibc -lrtemscpu -Wl,--end-group \
        -Wl,--script=linkcmds -B/tmp/edilibtmp/edilib/library -lgcc