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https://github.com/autc04/Retro68.git
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67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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float truncf(float x)
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#else
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float truncf(x)
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float x;
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#endif
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{
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__int32_t signbit, w, exponent_less_127;
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GET_FLOAT_WORD(w,x);
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/* Extract sign bit. */
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signbit = w & 0x80000000;
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/* Extract exponent field. */
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exponent_less_127 = ((w & 0x7f800000) >> 23) - 127;
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if (exponent_less_127 < 23)
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{
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if (exponent_less_127 < 0)
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{
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/* -1 < x < 1, so result is +0 or -0. */
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SET_FLOAT_WORD(x, signbit);
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}
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else
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{
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SET_FLOAT_WORD(x, signbit | (w & ~(0x007fffff >> exponent_less_127)));
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}
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}
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else
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{
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if (exponent_less_127 == 255)
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/* x is NaN or infinite. */
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return x + x;
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/* All bits in the fraction field are relevant. */
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}
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return x;
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}
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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double trunc(double x)
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#else
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double trunc(x)
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double x;
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#endif
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{
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return (double) truncf((float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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