overview-manual, ref-manual, dev-manual: Moved x32 stuff

Fixes [YOCTO #12370]

The section on the x32 psABI topic was in the "technical details"
section of the reference manual.  This section combined conceptual
and "how to" information for x32 psABI.  I moved the conceptual
information to a new chapter in the overview-manual.  I moved the
"how-to" information to a separate topic in the dev-manual.  This
resulted in the mega-manual being updated to take on a new chapter
for the overview-manual (overview-concepts.xml).  No links were
affected.

(From yocto-docs rev: 84da28a4ad0f3f89bfc865f410a5d06b57439beb)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 80 insertions, 0 deletions

diff --git a/documentation/overview-manual/overview-concepts.xml b/documentation/overview-manual/overview-concepts.xml
new file mode 100644
index 0000000000..dea30bc907
--- /dev/null
+++ b/documentation/overview-manual/overview-concepts.xml
@@ -0,0 +1,78 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+
+<chapter id='overview-concepts'>
+<title>Yocto Project Concepts</title>
+
+    <para>
+        This chapter presents key Yocto Project concepts.
+    </para>
+
+<section id='x32'>
+    <title>x32 psABI</title>
+
+    <para>
+        x32 processor-specific Application Binary Interface
+        (<ulink url='https://software.intel.com/en-us/node/628948'>x32 psABI</ulink>)
+        is a native 32-bit processor-specific ABI for
+        <trademark class='registered'>Intel</trademark> 64 (x86-64)
+        architectures.
+        An ABI defines the calling conventions between functions in a
+        processing environment.
+        The interface determines what registers are used and what the sizes are
+        for various C data types.
+    </para>
+
+    <para>
+        Some processing environments prefer using 32-bit applications even when
+        running on Intel 64-bit platforms.
+        Consider the i386 psABI, which is a very old 32-bit ABI for Intel
+        64-bit platforms.
+        The i386 psABI does not provide efficient use and access of the
+        Intel 64-bit processor resources, leaving the system underutilized.
+        Now consider the x86_64 psABI.
+        This ABI is newer and uses 64-bits for data sizes and program pointers.
+        The extra bits increase the footprint size of the programs, libraries,
+        and also increases the memory and file system size requirements.
+        Executing under the x32 psABI enables user programs to utilize CPU
+        and system resources more efficiently while keeping the memory
+        footprint of the applications low.
+        Extra bits are used for registers but not for addressing mechanisms.
+    </para>
+
+    <para>
+        The Yocto Project supports the final specifications of x32 psABI
+        as follows:
+        <itemizedlist>
+            <listitem><para>
+                You can create packages and images in x32 psABI format on
+                x86_64 architecture targets.
+                </para></listitem>
+            <listitem><para>
+                You can successfully build recipes with the x32 toolchain.
+                </para></listitem>
+            <listitem><para>
+                You can create and boot
+                <filename>core-image-minimal</filename> and
+                <filename>core-image-sato</filename> images.
+                </para></listitem>
+            <listitem><para>
+                RPM Package Manager (RPM) support exists for x32 binaries.
+                </para></listitem>
+            <listitem><para>
+                Support for large images exists.
+                </para></listitem>
+        </itemizedlist>
+    </para>
+
+    <para>
+        For steps on how to use x32 psABI, see the
+        "<ulink url='&YOCTO_DOCS_DEV_URL;#using-x32-psabi'>Using x32 psABI</ulink>"
+        section in the Yocto Project Development Tasks Manual.
+    </para>
+</section>
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->
diff --git a/documentation/overview-manual/overview-manual.xml b/documentation/overview-manual/overview-manual.xml
index 9af914a924..fe021073da 100644
--- a/documentation/overview-manual/overview-manual.xml
+++ b/documentation/overview-manual/overview-manual.xml
@@ -86,6 +86,8 @@
 
     <xi:include href="overview-development-environment.xml"/>
 
+    <xi:include href="overview-concepts.xml"/>
+
 </book>
 <!--
 vim: expandtab tw=80 ts=4