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<?xml version="1.0" encoding="UTF-8"?>
Copyright (c) 2017 OpenPOWER Foundation
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.
<section xmlns=""
<title>How did I find this out?</title>
<para>The next question is where did I get the details above. The GCC
documentation for <emphasis role="bold"><literal>__builtin_ia32_loadupd</literal></emphasis>
provides minimal information (the
builtin name, parameters and return types). Not very informative. </para>
<para>Looking up the Intel intrinsic description is more informative. You
can Google the intrinsic name or use the
<link xlink:href="">Intel
Intrinsic guide</link> for this. The Intrinsic Guide is interactive and
includes  Intel (Chip) technology and text based search capabilities. Clicking
on the intrinsic name opens to a synopsis including; the underlying instruction
name, text description, operation pseudo code, and in some cases performance
information (latency and throughput).</para>
<para>The key is to get a description of the intrinsic (operand fields and
types, and which fields are updated for the result) and the underlying Intel
instruction. If the Intrinsic guide is not clear you can look up the
instruction details in the
<link xlink:href="">Intel® 64 and IA-32
Architectures Software Developer’s Manual</link>”.</para>
<para>Information about the PowerISA vector facilities is found in the
<link xlink:href="">PowerISA Version 2.07B</link> (for POWER8 and
<link xlink:href="">3.0 for
POWER9</link>) manual, Book I, Chapter 6. Vector Facility and Chapter 7.
Vector-Scalar Floating-Point Operations. Another good reference is the
<link xlink:href="">OpenPOWER ELF V2 application binary interface</link> (ABI)
document, Chapter 6. Vector Programming Interfaces and Appendix A. Predefined
Functions for Vector Programming.</para>
<para>Another useful document is the original <link xlink:href="">Altivec Technology Programmers Interface Manual</link>
with a user friendly structure and many helpful diagrams. But alas the PIM does does not
cover the recent PowerISA (power7,  power8, and power9) enhancements.</para>