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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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* From: @(#)s_floor.c 5.1 93/09/24 |
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*/ |
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/* |
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* truncl(x) |
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* Return x rounded toward 0 to integral value |
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* Method: |
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* Bit twiddling. |
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* Exception: |
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* Inexact flag raised if x not equal to truncl(x). |
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*/ |
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#include <sys/types.h> |
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#include <machine/ieee.h> |
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#include <float.h> |
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#include <math.h> |
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#include <stdint.h> |
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#include "math_private.h" |
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#ifdef LDBL_IMPLICIT_NBIT |
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#define MANH_SIZE (EXT_FRACHBITS + 1) |
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#else |
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#define MANH_SIZE EXT_FRACHBITS |
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#endif |
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static const long double huge = 1.0e300; |
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static const float zero[] = { 0.0, -0.0 }; |
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long double |
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truncl(long double x) |
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{ |
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int e, es; |
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uint32_t ix0, ix1; |
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GET_LDOUBLE_WORDS(es,ix0,ix1,x); |
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e = (es&0x7fff) - LDBL_MAX_EXP + 1; |
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if (e < MANH_SIZE - 1) { |
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if (e < 0) { /* raise inexact if x != 0 */ |
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if (huge + x > 0.0) |
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return (zero[(es&0x8000)!=0]); |
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} else { |
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uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1); |
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if (((ix0 & m) | ix1) == 0) |
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return (x); /* x is integral */ |
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if (huge + x > 0.0) { /* raise inexact flag */ |
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ix0 &= ~m; |
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ix1 = 0; |
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} |
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} |
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} else if (e < LDBL_MANT_DIG - 1) { |
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uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1); |
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if ((ix1 & m) == 0) |
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return (x); /* x is integral */ |
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if (huge + x > 0.0) /* raise inexact flag */ |
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ix1 &= ~m; |
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} |
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SET_LDOUBLE_WORDS(x,es,ix0,ix1); |
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return (x); |
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} |