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<title>Integers implementation - Using the GNU Compiler Collection (GCC)</title>
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<a name="Integers-implementation"></a>
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Next: <a rel="next" accesskey="n" href="Floating-point-implementation.html#Floating-point-implementation">Floating point implementation</a>,
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Previous: <a rel="previous" accesskey="p" href="Characters-implementation.html#Characters-implementation">Characters implementation</a>,
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Up: <a rel="up" accesskey="u" href="C-Implementation.html#C-Implementation">C Implementation</a>
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<h3 class="section">4.5 Integers</h3>
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<ul>
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<li><cite>Any extended integer types that exist in the implementation (C99
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and C11 6.2.5).</cite>
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<p>GCC does not support any extended integer types.
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<!-- The __mode__ attribute might create types of precisions not -->
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<!-- otherwise supported, but the syntax isn't right for use everywhere -->
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<!-- the standard type names might be used. Predefined typedefs should -->
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<!-- be used if any extended integer types are to be defined. The -->
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<!-- __int128_t and __uint128_t typedefs are not extended integer types -->
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<!-- as they are generally longer than the ABI-specified intmax_t. -->
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<li><cite>Whether signed integer types are represented using sign and magnitude,
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two's complement, or one's complement, and whether the extraordinary value
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is a trap representation or an ordinary value (C99 and C11 6.2.6.2).</cite>
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<p>GCC supports only two's complement integer types, and all bit patterns
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are ordinary values.
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<li><cite>The rank of any extended integer type relative to another extended
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integer type with the same precision (C99 and C11 6.3.1.1).</cite>
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<p>GCC does not support any extended integer types.
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<!-- If it did, there would only be one of each precision and signedness. -->
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<li><cite>The result of, or the signal raised by, converting an integer to a
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signed integer type when the value cannot be represented in an object of
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that type (C90 6.2.1.2, C99 and C11 6.3.1.3).</cite>
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<p>For conversion to a type of width N, the value is reduced
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modulo 2^N to be within range of the type; no signal is raised.
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<li><cite>The results of some bitwise operations on signed integers (C90
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6.3, C99 and C11 6.5).</cite>
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<p>Bitwise operators act on the representation of the value including
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both the sign and value bits, where the sign bit is considered
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immediately above the highest-value value bit. Signed ‘<samp><span class="samp">>></span></samp>’ acts
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on negative numbers by sign extension.
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<p>GCC does not use the latitude given in C99 and C11 only to treat certain
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aspects of signed ‘<samp><span class="samp"><<</span></samp>’ as undefined, but this is subject to
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change.
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<li><cite>The sign of the remainder on integer division (C90 6.3.5).</cite>
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<p>GCC always follows the C99 and C11 requirement that the result of division is
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truncated towards zero.
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</ul>
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