<html lang="en"> <head> <title>Fixed-Point - Using the GNU Compiler Collection (GCC)</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Using the GNU Compiler Collection (GCC)"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="C-Extensions.html#C-Extensions" title="C Extensions"> <link rel="prev" href="Hex-Floats.html#Hex-Floats" title="Hex Floats"> <link rel="next" href="Named-Address-Spaces.html#Named-Address-Spaces" title="Named Address Spaces"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- Copyright (C) 1988-2015 Free Software Foundation, Inc. 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Support for fixed-point types in GCC will evolve as the draft technical report changes. Calling conventions for any target might also change. Not all targets support fixed-point types. <p>The fixed-point types are <code>short _Fract</code>, <code>_Fract</code>, <code>long _Fract</code>, <code>long long _Fract</code>, <code>unsigned short _Fract</code>, <code>unsigned _Fract</code>, <code>unsigned long _Fract</code>, <code>unsigned long long _Fract</code>, <code>_Sat short _Fract</code>, <code>_Sat _Fract</code>, <code>_Sat long _Fract</code>, <code>_Sat long long _Fract</code>, <code>_Sat unsigned short _Fract</code>, <code>_Sat unsigned _Fract</code>, <code>_Sat unsigned long _Fract</code>, <code>_Sat unsigned long long _Fract</code>, <code>short _Accum</code>, <code>_Accum</code>, <code>long _Accum</code>, <code>long long _Accum</code>, <code>unsigned short _Accum</code>, <code>unsigned _Accum</code>, <code>unsigned long _Accum</code>, <code>unsigned long long _Accum</code>, <code>_Sat short _Accum</code>, <code>_Sat _Accum</code>, <code>_Sat long _Accum</code>, <code>_Sat long long _Accum</code>, <code>_Sat unsigned short _Accum</code>, <code>_Sat unsigned _Accum</code>, <code>_Sat unsigned long _Accum</code>, <code>_Sat unsigned long long _Accum</code>. <p>Fixed-point data values contain fractional and optional integral parts. The format of fixed-point data varies and depends on the target machine. <p>Support for fixed-point types includes: <ul> <li>prefix and postfix increment and decrement operators (<code>++</code>, <code>--</code>) <li>unary arithmetic operators (<code>+</code>, <code>-</code>, <code>!</code>) <li>binary arithmetic operators (<code>+</code>, <code>-</code>, <code>*</code>, <code>/</code>) <li>binary shift operators (<code><<</code>, <code>>></code>) <li>relational operators (<code><</code>, <code><=</code>, <code>>=</code>, <code>></code>) <li>equality operators (<code>==</code>, <code>!=</code>) <li>assignment operators (<code>+=</code>, <code>-=</code>, <code>*=</code>, <code>/=</code>, <code><<=</code>, <code>>>=</code>) <li>conversions to and from integer, floating-point, or fixed-point types </ul> <p>Use a suffix in a fixed-point literal constant: <ul> <li>‘<samp><span class="samp">hr</span></samp>’ or ‘<samp><span class="samp">HR</span></samp>’ for <code>short _Fract</code> and <code>_Sat short _Fract</code> <li>‘<samp><span class="samp">r</span></samp>’ or ‘<samp><span class="samp">R</span></samp>’ for <code>_Fract</code> and <code>_Sat _Fract</code> <li>‘<samp><span class="samp">lr</span></samp>’ or ‘<samp><span class="samp">LR</span></samp>’ for <code>long _Fract</code> and <code>_Sat long _Fract</code> <li>‘<samp><span class="samp">llr</span></samp>’ or ‘<samp><span class="samp">LLR</span></samp>’ for <code>long long _Fract</code> and <code>_Sat long long _Fract</code> <li>‘<samp><span class="samp">uhr</span></samp>’ or ‘<samp><span class="samp">UHR</span></samp>’ for <code>unsigned short _Fract</code> and <code>_Sat unsigned short _Fract</code> <li>‘<samp><span class="samp">ur</span></samp>’ or ‘<samp><span class="samp">UR</span></samp>’ for <code>unsigned _Fract</code> and <code>_Sat unsigned _Fract</code> <li>‘<samp><span class="samp">ulr</span></samp>’ or ‘<samp><span class="samp">ULR</span></samp>’ for <code>unsigned long _Fract</code> and <code>_Sat unsigned long _Fract</code> <li>‘<samp><span class="samp">ullr</span></samp>’ or ‘<samp><span class="samp">ULLR</span></samp>’ for <code>unsigned long long _Fract</code> and <code>_Sat unsigned long long _Fract</code> <li>‘<samp><span class="samp">hk</span></samp>’ or ‘<samp><span class="samp">HK</span></samp>’ for <code>short _Accum</code> and <code>_Sat short _Accum</code> <li>‘<samp><span class="samp">k</span></samp>’ or ‘<samp><span class="samp">K</span></samp>’ for <code>_Accum</code> and <code>_Sat _Accum</code> <li>‘<samp><span class="samp">lk</span></samp>’ or ‘<samp><span class="samp">LK</span></samp>’ for <code>long _Accum</code> and <code>_Sat long _Accum</code> <li>‘<samp><span class="samp">llk</span></samp>’ or ‘<samp><span class="samp">LLK</span></samp>’ for <code>long long _Accum</code> and <code>_Sat long long _Accum</code> <li>‘<samp><span class="samp">uhk</span></samp>’ or ‘<samp><span class="samp">UHK</span></samp>’ for <code>unsigned short _Accum</code> and <code>_Sat unsigned short _Accum</code> <li>‘<samp><span class="samp">uk</span></samp>’ or ‘<samp><span class="samp">UK</span></samp>’ for <code>unsigned _Accum</code> and <code>_Sat unsigned _Accum</code> <li>‘<samp><span class="samp">ulk</span></samp>’ or ‘<samp><span class="samp">ULK</span></samp>’ for <code>unsigned long _Accum</code> and <code>_Sat unsigned long _Accum</code> <li>‘<samp><span class="samp">ullk</span></samp>’ or ‘<samp><span class="samp">ULLK</span></samp>’ for <code>unsigned long long _Accum</code> and <code>_Sat unsigned long long _Accum</code> </ul> <p>GCC support of fixed-point types as specified by the draft technical report is incomplete: <ul> <li>Pragmas to control overflow and rounding behaviors are not implemented. </ul> <p>Fixed-point types are supported by the DWARF 2 debug information format. </body></html>