Tree [a200b4] master /
 History

HTTPS access


File Date Author Commit
 aclocal 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 automake 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 bspkit 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 c 2009-12-11 Marc Pignat Marc Pignat [057b2e] Instrumentation: number of ticks since boot in ...
 cpukit 2010-03-12 Marc Pignat Marc Pignat [a200b4] Now fully tested
 doc 2010-02-23 Marc Pignat Marc Pignat [ed6a3b] fix typo in doc
 make 2009-09-02 Marc Pignat Marc Pignat [cd58ee] Cogent csb337 use the same cpu as the ARMEBS3, ...
 testsuites 2010-03-12 Marc Pignat Marc Pignat [3a37f7] Fix compilation when tracing is disable
 tools 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 .gitignore 2010-03-11 Marc Pignat Marc Pignat [2b3832] Added doxygen
 COPYING 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 ChangeLog 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 INSTALL 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 LICENSE 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 LICENSE.NET 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 LICENSE.RPCXDR 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 LICENSE.WEBSERVER 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 MAINTAINERS 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 Makefile.am 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 Makefile.in 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 README 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 README.cdn-X 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 README.configure 2009-09-02 Marc Pignat Marc Pignat [cd58ee] Cogent csb337 use the same cpu as the ARMEBS3, ...
 SUPPORT 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 TOOL_VERSIONS 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 VERSION 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 acinclude.m4 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 aclocal.m4 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 ampolish3 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 bootstrap 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 compile 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 config-ml.in 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 config.guess 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 config.sub 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 configure 2010-03-12 Marc Pignat Marc Pignat [c155a6] Fixed configure
 configure.ac 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 depcomp 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 install-sh 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 mdate-sh 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 missing 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped
 release_support 2009-09-02 Marc Pignat Marc Pignat [ba5891] Initial import of rtems-4.9.2
 texinfo.tex 2009-10-12 Marc Pignat Marc Pignat [ec1104] re-bootstrapped

Read Me

#
#  $Id: README,v 1.5 2000/09/01 07:19:16 joel Exp $
#

Building RTEMS
==============
See the file README.configure.

Directory Overview
==================

This is the top level of the RTEMS directory structure.  The following 
is a description of the files and directories in this directory:

  INSTALL
    Rudimentary installation instructions.  For more detailed
    information please see the Release Notes.  The Postscript 
    version of this manual can be found in the file
    c_or_ada/doc/relnotes.tgz.

  LICENSE
    Required legalese.

  README
    This file.

  c
    This directory contains the source code for the C 
    implementation of RTEMS as well as the test suites, sample 
    applications, Board Support Packages, Device Drivers, and 
    support libraries.

  doc
    This directory contains the PDL for the RTEMS executive.

Ada versus C
============

There are two implementations of RTEMS in this source tree -- 
in Ada and in C.  These two implementations are functionally
and structurally equivalent.  The C implementation follows
the packaging conventions and hierarchical nature of the Ada 
implementation.  In addition, a style has been followed which 
allows one to easily find the corresponding Ada and C 
implementations.  

File names in C and code placement was carefully designed to insure
a close mapping to the Ada implementation.  The following file name 
extensions are used:

   .adb - Ada body
   .ads - Ada specification
   .adp - Ada body requiring preprocessing
   .inc - include file for .adp files

   .c   - C body (non-inlined routines)
   .inl - C body (inlined routines)
   .h   - C specification

In the executive source, XYZ.c and XYZ.inl correspond directly to a 
single XYZ.adb or XYZ.adp file.  A .h file corresponds directly to
the .ads file.  There are only a handful of .inc files in the 
Ada source and these are used to insure that the desired simple 
inline textual expansion is performed.  This avoids scoping and
calling convention side-effects in carefully constructed tests 
which usually test context switch behavior.

In addition, in Ada code and data name references are always fully
qualified as PACKAGE.NAME.  In C, this convention is followed 
by having the package name as part of the name itself and using a
capital letter to indicate the presence of a "." level.  So we have
PACKAGE.NAME in Ada and _Package_Name in C.  The leading "_" in C
is used to avoid naming conflicts between RTEMS and user variables.
By using these conventions, one can easily compare the C and Ada
implementations.

The most noticeable difference between the C and Ada83 code is 
the inability to easily obtain a "typed pointer" in Ada83.  
Using the "&" operator in C yields a pointer with a specific type.
The 'Address attribute is the closest feature in Ada83.  This
returns a System.Address and this must be coerced via Unchecked_Conversion
into an access type of the desired type.  It is easy to view 
System.Address as similar to a "void *" in C, but this is not the case.
A "void *" can be assigned to any other pointer type without an
explicit conversion.  

The solution adopted to this problem was to provide two routines for
each access type in the Ada implementation -- one to convert from
System.Address to the access type and another to go the opposite
direction.  This results in code which accomplishes the same thing
as the corresponding C but it is easier to get lost in the clutter
of the apparent subprogram invocations than the "less bulky"
C equivalent.

A related difference is the types which are only in Ada which are used 
for pointers to arrays.  These types do not exist and are not needed 
in the C implementation.

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks