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/* @(#)s_modf.c 5.1 93/09/24 */ |
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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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/* |
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* modfl(long double x, long double *iptr) |
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* return fraction part of x, and return x's integral part in *iptr. |
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* Method: |
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* Bit twiddling. |
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* |
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* Exception: |
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* No exception. |
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*/ |
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#include <math.h> |
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#include "math_private.h" |
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static const long double one = 1.0; |
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long double |
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modfl(long double x, long double *iptr) |
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{ |
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int32_t i0,i1,jj0; |
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u_int32_t i,se; |
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GET_LDOUBLE_WORDS(se,i0,i1,x); |
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jj0 = (se&0x7fff)-0x3fff; /* exponent of x */ |
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if(jj0<32) { /* integer part in high x */ |
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if(jj0<0) { /* |x|<1 */ |
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SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */ |
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return x; |
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} else { |
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i = (0x7fffffff)>>jj0; |
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if(((i0&i)|i1)==0) { /* x is integral */ |
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*iptr = x; |
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
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return x; |
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} else { |
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SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0); |
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return x - *iptr; |
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} |
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} |
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} else if (jj0>63) { /* no fraction part */ |
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*iptr = x*one; |
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/* We must handle NaNs separately. */ |
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if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1)) |
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return x*one; |
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
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return x; |
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} else { /* fraction part in low x */ |
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i = ((u_int32_t)(0x7fffffff))>>(jj0-32); |
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if((i1&i)==0) { /* x is integral */ |
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*iptr = x; |
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SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */ |
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return x; |
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} else { |
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SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i)); |
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return x - *iptr; |
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} |
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} |
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} |