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Document the part_set intrinsic.

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Reid Spencer 2007-04-11 23:23:49 +00:00
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@ -184,7 +184,8 @@
<li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
<li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
<li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
<li><a href="#int_part_select">'<tt>llvm.part_select.*</tt>' Intrinsic </a></li>
<li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
<li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
</ol>
</li>
<li><a href="#int_debugger">Debugger intrinsics</a></li>
@ -4641,6 +4642,56 @@ only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
</ol>
</div>
<div class="doc_subsubsection">
<a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
on any integer bit width.
<pre>
declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
</pre>
<h5>Overview:</h5>
<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
of bits in an integer value with another integer value. It returns the integer
with the replaced bits.</p>
<h5>Arguments:</h5>
<p>The first argument, <tt>%val</tt> and the result may be integer types of
any bit width but they must have the same bit width. <tt>%val</tt> is the value
whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
type since they specify only a bit index.</p>
<h5>Semantics:</h5>
<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
of operation: forwards and reverse. If <tt>%lo</tt> is greater than
<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
operates in forward mode.</p>
<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
truncating it down to the size of the replacement area or zero extending it
up to that size.</p>
<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
to the <tt>%hi</tt>th bit.
<p>In reverse mode, a similar computation is made except that the bits replaced
wrap around to include both the highest and lowest bits. For example, if a
16 bit value is being replaced then <tt>%lo=8</tt> and <tt>%hi=4</tt> would
cause these bits to be set: <tt>0xFF1F</p>.
<h5>Examples:</h5>
<pre>
llvm.part.set(0xFFFF, 0, Y, 4, 7) -&gt; 0xFF0F
llvm.part.set(0xFFFF, 0, Y, 7, 4) -&gt; 0x0060
llvm.part.set(0xFFFF, 0, Y, 8, 3) -&gt; 0x00F0
llvm.part.set(0xFFFF, 0, Y, 3, 8) -&gt; 0xFE07
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="int_debugger">Debugger Intrinsics</a>