RELEASE NOTES
=============

Product   : GNU C/C++ Compiler Toolkit for ARC Processors
MileStone : Release of the gcc-4.2.1 based toolchain
Version   : GNU Binutils 2.15-celunite-release-20071106
	    GCC version 4.2.1 (Celunite-Release-20071106)
Date      : November 06, 2007

Table of Contents
-----------------

1.  Overview
2.  Features Supported
3.  Major changes in this release
4.  Known Limitations and Defects
5.  Contact Information
6.  Reference 


1.  Overview
------------
	This is the first release of the gcc-4.2.1 based compiler
    toolchain for the ARC cores. For limitations and known issues with this
    release please refer to section 4 below.

2.  Features Supported
----------------------

    2.1 Features of 4.2.1 release #1 (November 06 2007)
    -----------------------------------------------------------
    * GCC for ARC has been upgraded to gcc-4.2.1
    * The back-end has been completely reviewed and revamped to
    provide better coverage of the ARCompact instruction set.
    * Small-data support has been added to the toolchain.
    * Support for generation of constant-pools has been added to the toolchain.
    * Support for generating millicode for save-restore in pro/epilog
    has been added to the compiler.
    * Instruction costs have been modified for better instruction
    selection when optimizing for size.
    * Support for trampolines has been added to the compiler.
    * Bug in generation of pre-compiled headers has been fixed.
    * uClibc has been modified to build with gcc-4.2
    * FPX support has been incorporated for ARC.
    * Support for generation of ARC SIMD extension instructions by using new
    built-in functions has been incorporated into the toolchain.
    * New builtin functions have been added for generation of the
    following instructions:
	      - RTIE
	      - SYNC
    * The following target switches have been added to the toolchain:
	      -mno-const-pool
	      -mspfp
	      -mspfp_fast
	      -mspfp_compact
	      -mdpfp
	      -mdpfp_fast
	      -mdpfp_compact
	      -mno-sdata
	      -msimd
	      -mno-millicode
      For description of these switches, please refer to gcc info pages for this
    release, or the ARC GNU Tools User Guide included in this release.
    * Separate crosstool scripts for generation of linux-uclibc toolchains 
    with and without dynamic-linking support.
    * Various bug fixes and code cleanups.
    * Overall incremental front-end changes in gcc since the 3.4.x
    branch can be seen at:
      a) http://gcc.gnu.org/gcc-4.0/changes.html 
      b) http://gcc.gnu.org/gcc-4.1/changes.html
      c) http://gcc.gnu.org/gcc-4.2/changes.html

3. Major back-end changes in this release
----------------------------------------- 
    * Several code generation changes have been made for constant-pool
    generation.
    * The linux-uclibc toolchain generates dynamically linking executables by 
    default. For static binaries, the '-static' flag has to be passed explicitly.

      For the list of changes in the earlier releases, please see the
    corresponding release notes.

4. Known Limitations and Defects
--------------------------------
    * C++ support is not available on uClinux target.
    * Stack protection library (libssp) has been disabled.
    * Sibling-calls have been disabled for PIC.
    * Using simd data types in non-builtin operations causes compiler
    crashes in some cases. 

5. Contact Information  
----------------------
   If you have a support contract, please use the support site at 
   http://arc-linux.org.
 
6. References
-------------
    * ARC700 ISA Reference Manual
    * ARC GNU Tools User Guide
    * Sys V ABI Extension for ELF for the ARC
    * ARC Floating Point Reference
    * Aurora SIMD extensions to the ARC700 ISA.
    * The finite state automaton based pipeline hazard recognizer and
      instruction scheduler in GCC 
      - by Vladimir N. Makarov (GCC Summit 2003 proceedings)
      [Link: http://www.gccsummit.org/2003 ]



Tools Team 
Celunite Soft Systems India Pvt. Ltd.