Release Notes for SystemC 2.3.0 Release Of 21 November 2011
        ===========================================================

CONTENTS
========

  1) What's new in this release?

  2) Bug fixes and enhancements

  3) New features

  4) Incompatibitilies with previous releases

  5) Expanded dynamic process support

  6) Experimental features

  7) Known problems

  8) Fixed-point library


1) What's new in this release?
==============================

Compared to the 2.2.0, this release has the following new items:

  - This version of SystemC contains the "Proof of Concept" simulator
    for the IEEE 1666_2011 SystemC standard. Please consult the IEEE
    1666_2011 Language Reference Manual for details about the new SystemC
    standard.

  - Bug fixes, see section 2.

  - Expanded dynamic process capabilities, see section 5.

  - Expanded platform support, see the README.


2) Bug fixes and enhancements
=============================

Following is the list of bug fixes and enhancements for this release:

     - Removed quick threads header inclusion from public includes.

     - Added free BSD support to configure and cleaned up other issues.

     - Plugged memory leak in sc_signal destructors associated with 
       sc_event instances.

     - Fixed namespace collision issue with sc_boost support.

     - Process control improvements: 
         (a) Fixed bug in hierarchical killing of processes.
	 (b) Changes to when deleted processes are actually deleted.
	 (c) Retain process objects as zombies until all of their children 
	     have been removed.

     - Replaced last uses of sc_pvector with std::vector<>.

     - Changes to sc_process handle to use a copy/swap idiom for implementing
       operator = so that the reference counts work properly.

     - Fixed memory leak and race condition in sc_event_queue.

     - Removed internal objects from the object hierarchy for IEEE 1666
       compatibility.

     - Moved default parameter specifications from friend declarations to
       the actual function signatures in the fixed point support.

       src/sysc/datatypes/fx/scfx_rep.h

     - The default stack size for threads, SC_DEFAULT_STACK_SIZE, has been 
       increased from 64K bytes to 128K bytes. This setting is controlled 
       with a #define, so if necessary, you can set it back to 64K bytes 
       in your version.

       src/sysc/kernel/sc_constants.h

     - sc_concref uses for 8 cases involving bool or char* operands failed
       to release the storage they allocated. This has been fixed.

         src/sysc/datatypes/bit/sc_lv_base.h

     - sc_concatref did not have shift operator overloads for the int shift
       value. It has been added.

       src/sysc/datatypes/misc/sc_concatref.h

     - Plugged a memory leak in operator - for sc_signed operations. If 
       the two operands were equal it returned a new sc_signed instance 
       of zero, but did not free its temporary buffer.

     - Added masking for the RADIX size to the conversion of double
       values to the internal representation of sc_unsigned and
       sc_signed values. Changes to sc_signed.cpp and sc_unsigned.cpp.

     - Added a static std::vector<sc_object*> field to the sc_object
       class to return for get_child_objects() rather than a dynamic
       allocation. Changes to sc_object.h and sc_object.cpp.

     - sc_mutex::lock() & sc_mutex::trylock() now allow owner to apply
       lock more than once without incident. Previous behavior locked 
       up the owning process.

     - Fixed list processing for attributes to match that of C++ Standard
       Library classes.
       
         src/sysc/utils/sc_vector.h
       
     - Changed .begin() and .end in sc_pvector<T> so that its use by
       sc_object::attr_cltn().begin() and .end() will return a null
       pointer if there are no attributes defined.

     - Fixed bug where concatenations involving sc_unsigned instances 
       with negative values, e.g., from ~X for instance, were returning 
       zero rather than the actual bits of the value.

     - Added sc_core namespace prefix in the sc_assert() macro.

     - When sc_stop() is called the message informing the user is now
       issued via SC_REPORT_INFO() rather than just output to cout.
     
     - Fixed bug for sc_bigint::and_reduce() where it was not properly
       detecting the all ones case.

     - Changed the default status value in sc_elab_and_sim() to be 1 
       rather than 0. This means a non-zero value will be returned
       if sc_main() generates an exception.

     - Fixed bug in auto-increment and auto-decrement of sc_signed and
       sc_unsigned values. The original code left the values in sign
       magnitude form and did not properly trim them. The code now uses
       *this = *this + 1 and *this = *this -1

     - Expanded naming of signals in sc_vcd_trace.cpp to use 5 characters
       rather than 3 to accommodate more signals.

     - The mask being used to construct concatenation read values for
       sc_int<W>, sc_uint<W>, and their part selection classes was 32 bits 
       when it should have been 64 bits. This meant that selections wider
       than 32 bits would fail. It is now 64 bits.

         src/sysc/datatypes/int/sc_int_base.cpp:
         src/sysc/datatypes/int/sc_uint_base.cpp:

     - Fix for logical operators between unsigned int and sc_unsigned

       src/sysc/datatypes/int/sc_nbcommon.inc

         Fixed bit width in CLASS_TYPE::CLASS_TYPE() for the case that
	 the signature is a buffer of digits and a width. The value of
	 nbits needs to be set via num_bits() rather than using the
	 nb parameter. This allows the case where CLASS_TYPE is 
	 sc_unsigned to get the proper bit width. Without this fix the
	 high order bit disappears in logical results.

     - Added "kill" assignment to sc_fifo::buf_read() so that things like
       boost::shared_ptr actually release.

     - Better writer and read checking for sc_fifo<T> ports. 

         src/sysc/communication/sc_fifo.h

            The port binder now checks for blocking interfaces in addition 
	    to the combined non-blocking - blocking interface.

     - Error message added if wait(N) is called from an SC_METHOD

         src/sysc/kernel/sc_wait_cthread.h

     - Null terminator placed on end of argv_copy.

         src/sysc/kernel/sc_main_main.cpp

     - Mac OS X support modified to accommodate Snow Leopard

         configure.in

       The support for i386 based Macintoshes now includes "-arch i386" 
       for the command line options for g++/gcc and as. This produces
       32-bit architecture libraries, as has been true in the past.

3) New features
===============

Here is an overview of changes in 2.3.0 compared to 2.2.0:

  - Expanded dynamic process capabilities, see section 5.

  - A number of other changes to SystemC functions and classes, e.g.,
    sc_start() for the new IEEE 1666 standard, IEEE 1666_2011. See the
    IEEE 1666_2011 Language Reference Manual for details.

  - Boost library used by SystemC is now in the namespace sc_boost 
    rather than boost. This allows SystemC-based programs to be 
    combined with programs using later versions of the boost library.

    Note that to use OSCI TLM 2.0 with SystemC 2.3.0 you will need to
    add the following line before including systemc.h:

       #define sc_boost boost

    This will change the namespace back to boost, which is necessary to
    compile TLM 2.0 based applications.

  - Addition of sc_prim_channel::async_request_update(). To use this
    feature you must compile your simulator with SC_INCLUDE_ASYNC_UPDATES
    defined.


4) Incompatibilities with previous releases
===========================================

Here is a list of known incompatibilities between this release and 2.2.0:

  - The order that processes (SC_METHODS and SC_THREADS) are dispatched 
    for execution may be different than the order with SystemC 2.2.0 for
    some SystemC programs. This is related to the new starvation policy 
    support for the sc_start() function introduced with IEEE 1666_2011.

  - The various bind() functions for ports and exports are "virtual" as
    of IEEE 1666-2011.  This leads to an incompatibility with the
    TLM 2.0.x release.  To use SystemC 2.3 together with TLM 2.0.x,
    define SC_DISABLE_VIRTUAL_BIND during the build of the simulator and
    before including systemc.h.

5) Expanded Dynamic Process Support
===================================

- This version implements the dynamic process extensions described in the 
  IEEE 1666_2011 Language Reference Manual.


6) Experimental features
========================

In this section the experimental features of this release are listed.

  - None

7) Known Problems       
=================

  - The use of the DEBUG_SYSTEMC macro does not work properly with certain
    compilers (e.g., gcc 2.95.x) if it was not also specified when the
    SystemC library was built. The problem is caused by the use of the
    library compiled version of some inline methods. This problem does not
    appear to be present in the gcc 3.3, Solaris, and aCC compilers.
    The work-around is to specify DEBUG_SYSTEMC when the SystemC library
    is built.


8) Fixed-point library
======================

(No change from 2.0.1 Production.)

SystemC contains a fixed-point datatypes package.

Compile-time macro SC_INCLUDE_FX must be defined in order to build
applications that use fixed point types. You can specify a compiler
flag, e.g. g++ -DSC_INCLUDE_FX ... or use a define statement before
you include systemc.h, e.g.

  #define SC_INCLUDE_FX
  #include "systemc.h"

Due to the large size of the fixed-point datatypes header files,
compilation can take considerably more time.

If you want to use the fixed-point data types only (i.e., not data-
types sc_int, sc_uint, sc_bigint, sc_biguint), compilation time can be
reduced by defining compile-time macro SC_FX_EXCLUDE_OTHER (in addition
to SC_INCLUDE_FX).