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update the bytecode format guide for the encoding of inline asm. 

llvm-svn: 25622
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Chris Lattner 2006-01-25 23:31:53 +00:00
parent 4470691999
commit 4e27e8d71b
1 changed files with 61 additions and 9 deletions
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llvm/docs/BytecodeFormat.html
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@ -1275,16 +1275,21 @@ for the details. </p>
</tbody>
</table>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"><a name="constant">Constant Field</a></div>
<div class="doc_subsubsection"><a name="constant">Simple Constant Pool
Entries</a></div>
<div class="doc_text">
<p>Constants come in many shapes and flavors. The sections that follow
define the format for each of them. All constants start with a <a
<p>Constant pool entries come in many shapes and flavors. The sections that
follow define the format for each of them. All constants start with a <a
href="#uint32_vbr">uint32_vbr</a> encoded integer that provides the
number of operands for the constant. For primitive, structure, and
array constants, this will always be zero since those types of
constants have no operands. In this case, we have the following field
definitions:</p>
array constants, this will always be zero to indicate that the form of the
constant is solely determined by its type. In this case, we have the following
field definitions, based on type:</p>
<ul>
<li><b>Bool</b>. This is written as an <a href="#uint32_vbr">uint32_vbr</a>
of value 1U or 0U.</li>
@ -1303,12 +1308,59 @@ element values.</li>
field values of the structure.</li>
</ul>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">Undef Entries</a></div>
<div class="doc_text">
<p>When the number of operands to the constant is one, we have an 'undef' value
of the specified type.</p>
</div>
<p>When the number of operands to the constant is greater than one, we have a
constant expression and its field format is provided in the table below, and the
number is equal to the number of operands+1.</p>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">Inline Assembler Entries</a></div>
<div class="doc_text">
<p>Inline Assembler entries are stored in the constant pool, though they are not
officially LLVM constants. These entries are marked with a value of
"4294967295" (all ones) for the number of operands. They are encoded as
follows:</p>
<table>
<tbody>
<tr>
<th><b>Type</b></th>
<th class="td_left"><b>Field Description</b></th>
</tr>
<tr>
<td><a href="#string">string</a></td>
<td class="td_left">The asm string.</td>
</tr>
<tr>
<td><a href="#string">string</a></td>
<td class="td_left">The constraints string.</td>
</tr>
<tr>
<td><a href="#uint32_vbr">uint32_vbr</a></td>
<td class="td_left">Flags</sup></td>
</tr>
</tbody>
</table>
<p>Currently, the only defined flag, the low bit, indicates whether or not the
inline assembler has side effects.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">Constant Expression Entries</a></div>
<div class="doc_text">
<p>Otherwise, we have a constant expression. The format of the constant
expression is specified in the table below, and the number is equal to the
number of operands+1.</p>
<table>
<tbody>
<tr>