79 lines
1.6 KiB
C
79 lines
1.6 KiB
C
/*
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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 roundf(float x)
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#else
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float roundf(x)
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float x;
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#endif
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{
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int signbit;
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__uint32_t w;
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/* Most significant word, least significant word. */
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int 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 = (int)((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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w &= 0x80000000;
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if (exponent_less_127 == -1)
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/* Result is +1.0 or -1.0. */
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w |= (127 << 23);
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}
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else
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{
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unsigned int exponent_mask = 0x007fffff >> exponent_less_127;
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if ((w & exponent_mask) == 0)
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/* x has an integral value. */
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return x;
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w += 0x00400000 >> exponent_less_127;
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w &= ~exponent_mask;
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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 == 128)
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/* x is NaN or infinite. */
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return x + x;
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else
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return x;
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}
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SET_FLOAT_WORD(x, w);
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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 round(double x)
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#else
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double round(x)
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double x;
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#endif
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{
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return (double) roundf((float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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