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| <a name="Decimal-Floating-Point-format"></a> |
| <h4 class="subsubsection">15.4.1.8 Decimal Floating Point format</h4> |
| <a name="index-decimal-floating-point-format"></a> |
| |
| <p><small>GDB</small> 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> |
| <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. <small>GDB</small> will use the appropriate encoding for the |
| configured target. |
| </p> |
| <p>Because of a limitation in <samp>libdecnumber</samp>, the library used by <small>GDB</small> |
| 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> |
| <p>In addition, in order to imitate <small>GDB</small>’s behaviour with binary floating |
| point computations, error checking in decimal float operations ignores |
| underflow, overflow and divide by zero exceptions. |
| </p> |
| <p>In the PowerPC architecture, <small>GDB</small> 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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