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#
#  $Id: README.configure,v 1.2 2001-09-27 11:59:04 chris Exp $
#

1. Autoconf support
===================

This version of RTEMS is configured with GNU autoconf. RTEMS can be
configured and built either standalone or together with the compiler
tools in the Cygnus one-tree structure. Using autoconf also means
that RTEMS now can be built in a separate build directory.

2. Installation
===============

2.1 Standalone build

To configure RTEMS for a specific target, run configure in the build
directory. In addition to the standard configure options, the following
RTEMS-specific option are supported:

        --disable-rtems-inlines
        --disable-posix
        --disable-itron
        --disable-networking
        --enable-cxx
        --enable-bare-cpu-model=<MODEL>
        --enable-bare-cpu-cflags=<FLAGS>
        --enable-gcc28               (also use enable-libcdir when disabled)
        --enable-libcdir=<DIRECTORY>      (do not use if gcc 2.8 is enabled)
        --enable-multiprocessing
        --enable-rtemsbsp="bsp1 bsp2 ..."
        --enable-tests
        --enable-rdbg            (only valid for i386 and some PowerPC BSPs)

In addition, the following standard autoconf options are frequently
used when configuring RTEMS installations:

        --prefix=INSTALL_DIRECTORY
        --program-prefix=

By default, inline routines are used instead of macros where possible.
Macros can be selected using the --disable-inlines option.  [NOTE:
Some APIs may not support macro versions of their inline routines.]

By default, the RTEMS POSIX 1003.1b interface is built for targets that support
it. It can be disabled with the --disable-posix option.

By default, the RTEMS uITRON interface is built for targets that support
it. It can be disabled with the --disable-itron option.

By default, the RTEMS networking support is built for targets which
support it.  It can be specifically disabled for those targets
with the --disable-networking option.

By default, the RTEMS remote debugger server support is not built.
It can be specifically enabled for the targets that support it.
with the --enable-rdbg option. NB : the RTEMS networking support
must be enabled to support the remote debugger server.

By default, the RTEMS support of C++ is disabled.  It can be enabled
with the --enable-cxx option. If the rtems++ C++ library is installed
it will also be build.

By default, the RTEMS test suites are NOT configured -- only the 
sample tests are built.  The --enable-tests will not configure
the RTEMS test suite. The default speeds up the build
and configure process when the tests are not desired.

By default, RTEMS is built using arguments and build rules which are 
NOT compatible with gcc 2.7.2.2.  If using a gcc which supports the
-specs option, then the --enable-gcc28 option may be used to enable
this feature.  You should use the --enable-gcc28 option when using
either the egcs source tree, testgcc snapshots, or gcc 2.8.0 or newer.
If you --disable-gcc28, then you MUST  specify the location of the
Standard C Library with the --enable-libcdir option.   [NOTE: These
options are considered obsolete and may be removed in a future
RTEMS release.]

By default, multiprocessing is is not built.  It can be enabled
for those BSPs supporting it by the --enable-multiprocessing option.

By default, all bsps for a target are built. The bare BSP is not built
unless directlty specified. There are  two ways of changing this:

  + use the --enable-rtemsbsp otion which will set the specified
    bsps as the default bsps, or 
  + set the RTEMS_BSP variable during make (see below).

The --enable-rtemsbsp= option configures RTEMS for a specific target
architecture.  The following targets are supported:

        (none)                  will build the host-based version on Linux,
                                Solaris and HPUX.

        a29k-rtems              only standalone, uses non-gnu compiler
        i386-rtems
        i960-rtems
        hppa1.1-rtems
        m68k-rtems
        mips64orion-rtems
        no_cpu-rtems
        powerpc-rtems
        sparc-rtems
        bare                    see notes
        
The cross-compiler is set to $(target)-gcc by default. This can be
overriden by:

  + using the --program-prefix option to configure to specify the
    string which will prepended to the tool names.  Be sure to include
    a trailing "-".  For example, to use a m68k-coff toolset, use the
    --program-prefix=m68k-coff- option.

To build, run make in the build directory. To specify which bsps to build,
add the RTEMS_BSP="bsp1 bsp2 .." to the make command.  Specifying multiple
BSPs to build only works from the top level build directory.

Installation is done under $(prefix)/rtems.

As an example, to build and install the mvme136 and dmv152 bsps for m68k do:

        (path_to_rtems_src)/configure --target=m68k-rtems

        make RTEMS_BSP="mvme136 dmv152"
        
        make install RTEMS_BSP="mvme136 dmv152"

The sample tests are built by 'make all', do a 'make test' to build the full
test suite.

2.2 Build with Cygnus one-tree release

To build and install RTEMS with the one-tree structure, just copy the rtems
directory to the tree. The one-tree configure.in and Makefile.in has to be 
replaced with the RTEMS-aware versions. The build options are the same as 
for the standalone build.

2.3 Target Dependent Notes

bare:

  1.  See the README in the bare bsp source directory. This should
      contain all info you need.
  2.  The bare bsp source contains a script to show how to build it.
  3.  The configure flags must be used to get the bare bsp to work.
      The --enable-bare-cpu-model and --enable-bare-cpu-cflags are the
      only pieces of information. The module is usually a gcc module
      such as m68302 or mcpu32. The flags are passed directly to gcc.
      Use "" if more than one option is specified.

3. To use the installed RTEMS library
=====================================

To use the installed RTEMS bsps to build applications, the application
makefile has to include a bsp-specific makefile that will define the
RTEMS variables necessary to find include files and libraries. The
bsp-specific makefile is installed at 

        $(RTEMS_MAKEFILE_PATH)/Makefile.inc

For the erc32 bsp installed at /usr/local/cross, the environment
variable RTEMS_MAKEFILE_PATH would be set as follows to the
following:

/usr/local/cross/sparc-rtems/rtems/erc32/Makefile.inc

4. Supported target bsps
========================

The following bsps are supported:

host-based      : posix (on linux, solaris and hpux)

a29k            : portsw
i386            : i386ex pc386
i960            : cvme961
hppa1.1         : simhppa
m68k            : dmv152 efi332 efi68k gen68302 gen68340 gen68360 
                  gen68360_040 idp mvme136 mvme147 mvme147s mvme162 ods68302
no_cpu          : no_bsp
mips64orion     : p4600 p4650 (p4000 port with either R4600 or R4650)
powerpc         : papyrus psim helas403
sh              : gensh1
sparc           : erc32
any             : bare

5. Makefile structure
=====================

The makefiles have been re-organised. Most gnu-based bsps now use three
main makefiles:
    + custom/default.cfg,
    + custom/bsp.cfg and
    + ompilers/gcc-target-default.cfg.

Default.cfg sets the deafult values of certain common build options.

Bsp.cfg set bsp-specific build options and can also override the
default settings.

Gcc-target-default.cfg contains the common gcc definitions. Some targets
(a29k, no_cpu, and posix) still use the old structure.

6. Adding a bsp
===============

The top-level configure.in has to be modified if a new target is added
or if a new bsp is to be built by default. The additions required is
basically to add which makefiles are to be created by configure and
to add the target to the selection statement. To re-generate
configure, autoconf-2.12 is needed.

7. Tested configurations
========================

All gnu-based bsps have been built on Linux. 
The native (posix) ports have been built and run only on Linux.

The following configurations have NOT been tested:

    + Anything on Nextstep, HPUX and Irix.
    + The a29k port.

8. Pre-requisites
=================

Gawk version 2 or higher.
GNU make version 3.72 or higher.
Bash.
gcc version ???

TODO
====

The install-if-change script requires bash. On solaris systems, this should
be changed to ksh, since ksh is provided with solaris (bash not).

A fairly rescent version of gawk is needed to build RTEMS. This should be
changed so that a plain vanilla awk also works. [NOTE: This dependency
should disappear when the "gcc 2.8 -specs" is finished.]

'make install' should only install necessary files, not the full
PROJECT_RELEASE directory as now.

Posix port on solaris-2.5 fails due to undefined built-in functions
(gcc-2.7.2, might be my installation).

Improve support for 'make CFLAGS=xxx'.