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Completed incorporating portions of Chapter 6 from the ELFv2 ABI.

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Bill Schmidt 6 years ago
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commit 764e8333fa
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Intrinsics_Reference/ch_biendian.xml
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@ -66,6 +66,13 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="VIPR.biendian">
element order.
</para>

<note>
<para>
Much of the information in this chapter was formerly part of
Chapter 6 of the 64-Bit ELF V2 ABI Specification for POWER.
</para>
</note>

<section>
<title>Vector Data Types</title>
<para>
@ -86,9 +93,9 @@ xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="VIPR.biendian">
Elements" should precede this one.]
</para>
<para>
For the Fortran language, [FIXME: link to table in later
section] gives a correspondence between Fortran and C/C++
language types.
For the Fortran language, <xref
linkend="VIPR.biendian.fortran-types" /> gives a correspondence
between Fortran and C/C++ language types.
</para>
<para>
The assignment operator always performs a byte-by-byte data copy
@ -489,14 +496,6 @@ register vector double vd = vec_splats(*double_ptr);</programlisting>
big-endian and little-endian vector layouts and vector element
numberings.
</para>
<para>
For internal consistency, in the ELF V2 ABI, the default vector
layout and vector element ordering in big-endian environments
shall be big endian, and the default vector layout and vector
element ordering in little-endian environments shall be little
endian. [FIXME: Here's a purported ABI requirement; should this
somehow remain part of the ABI document?]
</para>
<para>
This element numbering shall also be used by the <code>[]</code>
accessor method to vector elements provided as an extension of
@ -725,9 +724,259 @@ register vector double vd = vec_splats(*double_ptr);</programlisting>
<section>
<title>Language-Specific Vector Support for Other
Languages</title>
<para>
filler
</para>
<section>
<title>Fortran</title>
<para>
<xref linkend="VIPR.biendian.fortran-types" /> shows the
correspondence between the C/C++ types described in this
document and their Fortran equivalents. In Fortran, the
Boolean vector data types are represented by
<code>VECTOR(UNSIGNED(</code><emphasis>n</emphasis><code>))</code>.
</para>
<table frame="all" pgwide="1" xml:id="VIPR.biendian.fortran-types">
<title>Fortran Vector Data Types</title>
<tgroup cols="2">
<colspec colname="c1" colwidth="50*" />
<colspec colname="c2" colwidth="50*" />
<thead>
<row>
<entry align="center">
<para>
<emphasis role="bold">XL Fortran Vector Type</emphasis>
</para>
</entry>
<entry align="center">
<para>
<emphasis role="bold">XL C/C++ Vector Type</emphasis>
</para>
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<para>VECTOR(INTEGER(1))</para>
</entry>
<entry>
<para>vector signed char</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(INTEGER(2))</para>
</entry>
<entry>
<para>vector signed short</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(INTEGER(4))</para>
</entry>
<entry>
<para>vector signed int</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(INTEGER(8))</para>
</entry>
<entry>
<para>vector signed long long, vector signed long<footnote
xml:id="vlongappalling">
<para>The vector long types are deprecated due to their
ambiguity between 32-bit and 64-bit environments. The use
of the vector long long types is preferred.</para>
</footnote></para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(INTEGER(16))</para>
</entry>
<entry>
<para>vector signed __int128</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(UNSIGNED(1))</para>
</entry>
<entry>
<para>vector unsigned char</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(UNSIGNED(2))</para>
</entry>
<entry>
<para>vector unsigned short</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(UNSIGNED(4))</para>
</entry>
<entry>
<para>vector unsigned int</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(UNSIGNED(8))</para>
</entry>
<entry>
<para>vector unsigned long long, vector unsigned long<footnoteref
linkend="vlongappalling" /></para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(UNSIGNED(16))</para>
</entry>
<entry>
<para>vector unsigned __int128</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(REAL(4))</para>
</entry>
<entry>
<para>vector float</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(REAL(8))</para>
</entry>
<entry>
<para>vector double</para>
</entry>
</row>
<row>
<entry>
<para>VECTOR(PIXEL)</para>
</entry>
<entry>
<para>vector pixel</para>
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
Because the Fortran language does not support pointers, vector
built-in functions that expect pointers to a base type take an
array element reference to indicate the address of a memory
location that is the subject of a memory access built-in
function.
</para>
<para>
Because the Fortran language does not support type casts, the
<code>vec_convert</code> and <code>vec_concat</code> built-in
functions shown in <xref linkend="VIPR.endian.convert" /> are
provided to perform bit-exact type conversions between vector
types.
</para>
<table frame="all" pgwide="1" xml:id="VIPR.endian.convert">
<title>Built-In Vector Conversion Functions</title>
<tgroup cols="2">
<colspec colname="c1" colwidth="30*" align="center" />
<colspec colname="c2" colwidth="70*" />
<thead>
<row>
<entry>
<para>
<emphasis role="bold">Group</emphasis>
</para>
</entry>
<entry align="center">
<para>
<emphasis role="bold">Description</emphasis>
</para>
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<para>VEC_CONCAT (ARG1, ARG2)<?linebreak?>(Fortran)</para>
<para></para>
</entry>
<entry>
<para>Purpose:</para>
<para>Concatenates two elements to form a vector.</para>
<para>Result value:</para>
<para>The resulting vector consists of the two scalar elements,
ARG1 and ARG2, assigned to elements 0 and 1 (using the
environment’s native endian numbering), respectively.</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Note: </emphasis>This function corresponds to the C/C++ vector
constructor (vector type){a,b}. It is provided only for
languages without vector constructors.</para>
</listitem>
</itemizedlist>
</entry>
</row>
<row>
<entry>
<para></para>
</entry>
<entry>
<para>vector signed long long vec_concat (signed long long,
signed long long);</para>
</entry>
</row>
<row>
<entry>
<para></para>
</entry>
<entry>
<para>vector unsigned long long vec_concat (unsigned long long,
unsigned long long);</para>
</entry>
</row>
<row>
<entry>
<para></para>
</entry>
<entry>
<para>vector double vec_concat (double, double);</para>
</entry>
</row>
<row>
<entry>
<para>VEC_CONVERT(V, MOLD)</para>
</entry>
<entry>
<para>Purpose:</para>
<para>Converts a vector to a vector of a given type.</para>
<para>Class:</para>
<para>Pure function</para>
<para>Argument type and attributes:</para>
<itemizedlist spacing="compact">
<listitem>
<para>V Must be an INTENT(IN) vector.</para>
</listitem>
<listitem>
<para>MOLD Must be an INTENT(IN) vector. If it is a
variable, it need not be defined.</para>
</listitem>
</itemizedlist>
<para>Result type and attributes:</para>
<para>The result is a vector of the same type as MOLD.</para>
<para>Result value:</para>
<para>The result is as if it were on the left-hand side of an
intrinsic assignment with V on the right-hand side.</para>
</entry>
</row>
</tbody>
</tgroup>
</table>
</section>
</section>

<section>

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