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59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS system libraries
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* FILE: lib/sdk/crt/float/fpclass.c
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* PURPOSE: Floating-point classes
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* PROGRAMER: Pierre Schweitzer (pierre@reactos.org)
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* REFERENCE: http://babbage.cs.qc.cuny.edu/IEEE-754/References.xhtml
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*/
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#include <precomp.h>
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#include <float.h>
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#include <internal/ieee.h>
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/*
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* @implemented
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*/
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int _fpclass(double __d)
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{
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union
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{
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double* __d;
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double_s* d;
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} d;
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d.__d = &__d;
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/* With 0x7ff, it can only be infinity or NaN */
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if (d.d->exponent == 0x7ff)
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{
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if (d.d->mantissah == 0 && d.d->mantissal == 0)
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{
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return (d.d->sign == 0) ? _FPCLASS_PINF : _FPCLASS_NINF;
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}
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/* Windows will never return Signaling NaN */
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else
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{
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return _FPCLASS_QNAN;
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}
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}
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/* With 0, it can only be zero or denormalized number */
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if (d.d->exponent == 0)
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{
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if (d.d->mantissah == 0 && d.d->mantissal == 0)
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{
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return (d.d->sign == 0) ? _FPCLASS_PZ : _FPCLASS_NZ;
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}
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else
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{
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return (d.d->sign == 0) ? _FPCLASS_PD : _FPCLASS_ND;
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}
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}
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/* Only remain normalized numbers */
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else
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{
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return (d.d->sign == 0) ? _FPCLASS_PN : _FPCLASS_NN;
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}
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}
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