Make updates for comments received so far, including issue #4 and

issue #5.  XL bug report support for Linux is still pending.
pull/30/head
Bill Schmidt 5 years ago
parent 029c89866f
commit 4a0e35f1d6

@ -32,7 +32,7 @@
xml:id="bk_main">

<!-- TODO: Pick a Title for the new document -->
<title>POWER Vector Intrinsic Programming Reference</title>
<title>Power Vector Intrinsic Programming Reference</title>
<!-- TODO: Either add a subtitle or remove the following line -->
<!-- subtitle></subtitle -->


@ -110,6 +110,14 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="VIPR.biendian">
</para>
<programlisting>vector int x = (vector int) (4, -1, 3, 6);
vector double g = (vector double) { 3.5, -24.6 };</programlisting>
<para>
Current C comiplers do not support literals for
<code>__int128</code> types. When constructing a <code>vector
__int128</code> constant from smaller literals such as
<code>int</code> or <code>long long</code>, you must test for
endianness and reverse the order of the smaller literals for
little-endian mode.
</para>
</section>

<section xml:id="VIPR.ch-data-types">
@ -584,6 +592,18 @@ register vector double vd = vec_splats(*double_ptr);</programlisting>
</tbody>
</tgroup>
</informaltable>
<note>
<para>
Note that each element in a vector has the same representation
in both big- and little-endian element orders. That is, an
<code>int</code> is always 32 bits, with the sign bit in the
high-order position. Programmers must be aware of this when
programming with mixed data types, such as an instruction that
multiplies two <code>short</code> elements to produce an
<code>int</code> element. Always access entire elements to
avoid potential endianness issues.
</para>
</note>
</section>

<section>
@ -1174,7 +1194,9 @@ register vector double vd = vec_splats(*double_ptr);</programlisting>
reorder entire elements of a vector. If you must use vec_perm
for another purpose, your code must include a test for
endianness and separate algorithms for big- and
little-endian.
little-endian. Examples of this may be seen in the Power
Vector Library project (see <xref linkend="VIPR.intro.links"
/>).
</para>
</section>
</section>

@ -79,16 +79,23 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="section_intro">
linkend="VIPR.intro.unified" />). The VSRs can represent all
the data types representable by the VRs, and can also be treated
as containing two 64-bit integers or two 64-bit double-precision
floating-point values.
floating-point values. However, ISA support for two 64-bit
integers in VSRs was limited until Version 2.07 (POWER8) of the
Power ISA, and only the VRs are supported for these
instructions.
</para>
<para>
Both the VMX and VSX instruction sets have been expanded for the
POWER8 and POWER9 processor families. Starting with POWER8,
a VSR can now contain a single 128-bit integer; and starting
with POWER9, a VSR can contain a single 128-bit floating-point
value. The VMX and VSX instruction sets together may be
referred to as the Power SIMD (single-instruction,
multiple-data) instructions.
value. Again, the ISA currently only supports 128-bit
operations on values in the VRs.
</para>
<para>
The VMX and VSX instruction sets together may be referred to as
the Power SIMD (single-instruction, multiple-data)
instructions.
</para>
<section>
<title>Little-Endian Linux</title>
@ -162,6 +169,50 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="section_intro">
</figure>
</section>

<section xml:id="VIPR.intro.reporting">
<title>Where to Report Bugs</title>
<para>
This reference provides guidance on using vector intrinsics that
are supported by all compatible compilers. If you find a
problem when using one of the intrinsics with a compatible
compiler, please report a bug! Bug reporting procedures differ
depending on which compiler you're using.
</para>
<itemizedlist>
<listitem>
<para>
<emphasis role="underline">GCC</emphasis>. The reporting
procedure for bugs against the GNU Compiler Collection is
described at <link
xlink:href="https://gcc.gnu.org/bugs/">https://gcc.gnu.org/bugs/</link>.
The GCC bugzilla tracker is located at <link
xlink:href="https://gcc.gnu.org/bugzilla/">https://gcc.gnu.org/bugzilla/</link>.
</para>
</listitem>
<listitem>
<para>
<emphasis role="underline">Clang/LLVM</emphasis>. The
reporting procedure for bugs against the Clang compiler is
described at <link
xlink:href="https://llvm.org/docs/HowToSubmitABug.html">https://llvm.org/docs/HowToSubmitABug.html</link>.
The LLVM bug tracking system is located at <link
xlink:href="https://bugs.llvm.org/enter_bug.cgi">https://bugs.llvm.org/enter_bug.cgi</link>.
</para>
</listitem>
<listitem>
<para>
<emphasis role="underline">The XL compilers</emphasis>.
</para>
<note>
<para>
Reporting procedures for XL bugs on Linux are yet to be
determined.
</para>
</note>
</listitem>
</itemizedlist>
</section>

<section xml:id="VIPR.intro.links">
<title>Useful Links</title>
<para>

@ -148,12 +148,19 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="section_techniques">
described here, you should look for an equivalent one in this
manual and change your code to use that.
</para>
<para>
Where an intrinsic may not be available from all compilers or at
all ISA levels, this information is called out in the
description of the intrinsic in <xref
linkend="VIPR.reference.vecfns" >.
</para>
<para>
There are also other vector APIs that may be of use to you (see
<xref linkend="VIPR.techniques.apis" />). In particular, the
Power Vector Library (see <xref
linkend="VIPR.techniques.pveclib" />) provides additional
portability across compiler versions.
portability across compiler versions, as well as interfaces that
hide cases where assembly language is needed.
</para>
</section>


@ -123,7 +123,10 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="VIPR.vec-ref">
<para>
<emphasis role="bold">ISA 3.0 or later</emphasis>. This
form is only available starting with PowerISA 3.0,
corresponding to POWER9 servers.
corresponding to POWER9 servers. The Power Vector Library
(see <xref linkend="VIPR.intro.links" /> provides equivalent
POWER7/POWER8 implementations for many ISA 3.0 vector
instructions, which may be preferred for portability.
</para>
</listitem>
<listitem>
@ -150,7 +153,7 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="VIPR.vec-ref">
</section>

<?hard-pagebreak?>
<section>
<section xml:id="VIPR.reference.vecfns">
<title>Built-In Vector Functions</title>

<simplesect xml:id="vec_abs">

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