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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - floating-point-exceptions in gallium/auxiliary/tgsi/ functions"
href="https://bugs.freedesktop.org/show_bug.cgi?id=108856">108856</a>
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<th>Summary</th>
<td>floating-point-exceptions in gallium/auxiliary/tgsi/ functions
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>18.2
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/OSMesa
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<th>Assignee</th>
<td>mesa-dev@lists.freedesktop.org
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<th>Reporter</th>
<td>popinet@basilisk.fr
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<th>QA Contact</th>
<td>mesa-dev@lists.freedesktop.org
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<div>
<pre>Calling the gallium osmesa implementation generates multiple floating-point
exceptions.
For example the src/gallium/auxiliary/tgsi/tgsi_exec.c:554, micro_rsq()
function contains the code:
dst->f[0] = 1.0f / sqrtf(src->f[0]);
and is sometimes called with src->f[0] == 0.
This is an important issue for (scientific) codes which typically turn
floating-point-exceptions on.
A workaround is to turn FPE off before each GL/OSmesa call and turn them back
on after.
Note that the non-gallium OSMesa implementation does not have this issue.</pre>
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