lib/crtdll/math/modf.c

   1 /* @(#)s_modf.c 1.3 95/01/18 */
   2 /*
   3  * ====================================================
   4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   5  *
   6  * Developed at SunSoft, a Sun Microsystems, Inc. business.
   7  * Permission to use, copy, modify, and distribute this
   8  * software is freely granted, provided that this notice
   9  * is preserved.
  10  * ====================================================
  11  */
  12
  13 #include <msvcrt/float.h>
  14 #include <msvcrt/math.h>
  15 #include <msvcrt/internal/ieee.h>
  16
  17
  18
  19 //static const double one = 1.0;
  20
  21 double modf(double __x, double *__i)
  22 {
  23         double_t * x = (double_t *)&__x;
  24         double_t * iptr = ( double_t *)__i;
  25
  26         int j0;
  27         unsigned int i;
  28         j0 = x->exponent - 0x3ff;  /* exponent of x */
  29         if(j0<20) {                     /* integer part in high x */
  30                 if(j0<0) {                  /* |x|<1 */
  31                         *__i = 0.0;
  32                         iptr->sign = x->sign;
  33                         return __x;
  34                 } else {
  35
  36                         if ( x->mantissah == 0 && x->mantissal == 0 ) {
  37                                 *__i = __x;
  38                                 return 0.0;
  39                         }
  40
  41                         i = (0x000fffff)>>j0;
  42                         iptr->sign = x->sign;
  43                         iptr->exponent = x->exponent;
  44                         iptr->mantissah = x->mantissah&(~i);
  45                         iptr->mantissal = 0;
  46                         if ( __x == *__i ) {
  47                                 __x = 0.0;
  48                                 x->sign = iptr->sign;
  49                                 return __x;
  50                         }
  51                         return __x - *__i;
  52                 }
  53         } else if (j0>51) {             /* no fraction part */
  54                 *__i = __x;
  55                 if ( _isnan(__x) || _isinf(__x) )
  56                         return __x;
  57
  58                 __x = 0.0;
  59                 x->sign = iptr->sign;
  60                 return __x;
  61         } else {                        /* fraction part in low x */
  62
  63                 i = ((unsigned)(0xffffffff))>>(j0-20);
  64                 iptr->sign = x->sign;
  65                 iptr->exponent = x->exponent;
  66                 iptr->mantissah = x->mantissah;
  67                 iptr->mantissal = x->mantissal&(~i);
  68                 if ( __x == *__i ) {
  69                         __x = 0.0;
  70                         x->sign = iptr->sign;
  71                         return __x;
  72                 }
  73                 return __x - *__i;
  74         }
  75 }
  76
  77
  78 long double modfl(long double __x, long double *__i)
  79 {
  80         long_double_t * x = (long_double_t *)&__x;
  81         long_double_t * iptr = (long_double_t *)__i;
  82
  83         int j0;
  84         unsigned int i;
  85         j0 = x->exponent - 0x3fff;  /* exponent of x */
  86
  87         if(j0<32) {                     /* integer part in high x */
  88                 if(j0<0) {                  /* |x|<1 */
  89                         *__i = 0.0L;
  90                         iptr->sign = x->sign;
  91                         return __x;
  92                 } else {
  93
  94                         i = ((unsigned int)(0xffffffff))>>(j0+1);
  95                         if ( x->mantissal == 0 && (x->mantissal & i) == 0 ) {
  96                                 *__i =  __x;
  97                                 __x = 0.0L;
  98                                 x->sign = iptr->sign;
  99                                 return __x;
 100                         }
 101                         iptr->sign = x->sign;
 102                         iptr->exponent = x->exponent;
 103                         iptr->mantissah = x->mantissah&((~i));
 104                         iptr->mantissal = 0;
 105
 106                         return __x - *__i;
 107                 }
 108         } else if (j0>63) {             /* no fraction part */
 109                 *__i = __x;
 110                 if (  _isnanl(__x) ||  _isinfl(__x)  )
 111                         return __x;
 112
 113                 __x = 0.0L;
 114                 x->sign = iptr->sign;
 115                 return __x;
 116         } else {                        /* fraction part in low x */
 117
 118                 i = ((unsigned int)(0xffffffff))>>(j0-32);
 119                 if ( x->mantissal == 0 ) {
 120                         *__i =  __x;
 121                         __x = 0.0L;
 122                         x->sign = iptr->sign;
 123                         return __x;
 124                 }
 125                 iptr->sign = x->sign;
 126                 iptr->exponent = x->exponent;
 127                 iptr->mantissah = x->mantissah;
 128                 iptr->mantissal = x->mantissal&(~i);
 129
 130                 return __x - *__i;
 131         }
 132 }