diff -r 688e721f79d4 Doc/c-api/apiabiversion.rst
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Doc/c-api/apiabiversion.rst	Thu Feb 28 12:33:18 2013 +0530
@@ -0,0 +1,42 @@
+.. highlightlang:: c
+
+.. _apiabiversion:
+
+***********************
+API and ABI Versioning
+***********************
+
+``PY_VERSION_HEX`` is the Python version number encoded in a single integer.
+If any extension module defines ``PY_LIMITED_API`` as same with ``PY_VERSION_HEX``
+then that module will work on the future Python releases but will fail to load
+in the older versions of Python due to missing symbols.
+
+For example if the ``PY_VERSION_HEX`` is set to ``0x030401a2``, the underlying
+version information can be found by treating it as a 32 bit number in
+the following manner:
+
+   +-------------------------+------------------------------------------------+
+   | Bits (big endian order) | Meaning                                        |
+   +=========================+================================================+
+   | :const:`1-8`            |  ``PY_MAJOR_VERSION`` (the ``3`` in            |
+   |                         |  ``3.4.1a2``)                                  |
+   +-------------------------+------------------------------------------------+
+   | :const:`9-16`           |  ``PY_MINOR_VERSION`` (the ``4`` in            |
+   |                         |  ``3.4.1a2``)                                  |
+   +-------------------------+------------------------------------------------+
+   | :const:`17-24`          |  ``PY_MICRO_VERSION`` (the ``1`` in            |
+   |                         |  ``3.4.1a2``)                                  |
+   +-------------------------+------------------------------------------------+
+   | :const:`25-28`          |  ``PY_RELEASE_LEVEL`` (``0xA`` for alpha,      |
+   |                         |  ``0xB`` for beta, ``0xC`` for release         |
+   |                         |  candidate and ``0xF`` for final), in this     |
+   |                         |  case it is alpha.                             |
+   +-------------------------+------------------------------------------------+
+   | :const:`29-32`          |  ``PY_RELEASE_SERIAL`` (the ``2`` in           |
+   |                         |  ``3.4.1a2``, zero for final releases)         |
+   +-------------------------+------------------------------------------------+
+
+Thus ``3.4.1a2`` is hexversion ``0x030401a2``.
+
+All the given macros are defined in :source:`Include/patchlevel.h`.
+
diff -r 688e721f79d4 Doc/c-api/index.rst
--- a/Doc/c-api/index.rst	Thu Feb 28 08:31:32 2013 +0200
+++ b/Doc/c-api/index.rst	Thu Feb 28 12:33:18 2013 +0530
@@ -23,3 +23,4 @@
    memory.rst
    objimpl.rst
    stable.rst
+   apiabiversion.rst
diff -r 688e721f79d4 Doc/c-api/stable.rst
--- a/Doc/c-api/stable.rst	Thu Feb 28 08:31:32 2013 +0200
+++ b/Doc/c-api/stable.rst	Thu Feb 28 12:33:18 2013 +0530
@@ -2,9 +2,9 @@
 
 .. _stable:
 
-**********************************
-Stable Appliction Binary Interface
-**********************************
+***********************************
+Stable Application Binary Interface
+***********************************
 
 Traditionally, the C API of Python will change with every release.
 Most changes will be source-compatible, typically by only adding API,
diff -r 688e721f79d4 Doc/library/sys.rst
--- a/Doc/library/sys.rst	Thu Feb 28 08:31:32 2013 +0200
+++ b/Doc/library/sys.rst	Thu Feb 28 12:33:18 2013 +0530
@@ -613,29 +613,7 @@
    :term:`struct sequence`  :data:`sys.version_info` may be used for a more
    human-friendly encoding of the same information.
 
-   The ``hexversion`` is a 32-bit number with the following layout:
-
-   +-------------------------+------------------------------------------------+
-   | Bits (big endian order) | Meaning                                        |
-   +=========================+================================================+
-   | :const:`1-8`            |  ``PY_MAJOR_VERSION``  (the ``2`` in           |
-   |                         |  ``2.1.0a3``)                                  |
-   +-------------------------+------------------------------------------------+
-   | :const:`9-16`           |  ``PY_MINOR_VERSION``  (the ``1`` in           |
-   |                         |  ``2.1.0a3``)                                  |
-   +-------------------------+------------------------------------------------+
-   | :const:`17-24`          |  ``PY_MICRO_VERSION``  (the ``0`` in           |
-   |                         |  ``2.1.0a3``)                                  |
-   +-------------------------+------------------------------------------------+
-   | :const:`25-28`          |  ``PY_RELEASE_LEVEL``  (``0xA`` for alpha,     |
-   |                         |  ``0xB`` for beta, ``0xC`` for release         |
-   |                         |  candidate and ``0xF`` for final)              |
-   +-------------------------+------------------------------------------------+
-   | :const:`29-32`          |  ``PY_RELEASE_SERIAL``  (the ``3`` in          |
-   |                         |  ``2.1.0a3``, zero for final releases)         |
-   +-------------------------+------------------------------------------------+
-
-   Thus ``2.1.0a3`` is hexversion ``0x020100a3``.
+   More details of ``hexversion`` can be found at :ref:`apiabiversion`
 
 
 .. data:: implementation