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<h5 class="subsubsection">15.4.1.8 Decimal Floating Point format</h5>

<p><a name="index-decimal-floating-point-format-1012"></a>
<span class="sc">gdb</span> can examine, set and perform computations with numbers in
decimal floating point format, which in the C language correspond to the
<code>_Decimal32</code>, <code>_Decimal64</code> and <code>_Decimal128</code> types as
specified by the extension to support decimal floating-point arithmetic.

   <p>There are two encodings in use, depending on the architecture: BID (Binary
Integer Decimal) for x86 and x86-64, and DPD (Densely Packed Decimal) for
PowerPC and S/390.  <span class="sc">gdb</span> will use the appropriate encoding for the
configured target.

   <p>Because of a limitation in <samp><span class="file">libdecnumber</span></samp>, the library used by <span class="sc">gdb</span>
to manipulate decimal floating point numbers, it is not possible to convert
(using a cast, for example) integers wider than 32-bit to decimal float.

   <p>In addition, in order to imitate <span class="sc">gdb</span>'s behaviour with binary floating
point computations, error checking in decimal float operations ignores
underflow, overflow and divide by zero exceptions.

   <p>In the PowerPC architecture, <span class="sc">gdb</span> provides a set of pseudo-registers
to inspect <code>_Decimal128</code> values stored in floating point registers. 
See <a href="PowerPC.html#PowerPC">PowerPC</a> for more details.

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