newlib/libc/stdlib/gdtoa-ldtoa.c

   1 /*      $OpenBSD: ldtoa.c,v 1.4 2016/03/09 16:28:47 deraadt Exp $       */
   2 /*-
   3  * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <newlib.h>
  29 #include <sys/config.h>
  30
  31 #ifdef _USE_GDTOA
  32 #include <sys/types.h>
  33 #include <machine/ieee.h>
  34 #include <float.h>
  35 #include <stdint.h>
  36 #include <limits.h>
  37 #include <math.h>
  38 #include <stdlib.h>
  39 #include "gdtoaimp.h"
  40
  41 #if (LDBL_MANT_DIG > DBL_MANT_DIG)
  42
  43 /*
  44  * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
  45  * except that the floating point argument is passed by reference.
  46  * When dtoa() is passed a NaN or infinity, it sets expt to 9999.
  47  * However, a long double could have a valid exponent of 9999, so we
  48  * use INT_MAX in ldtoa() instead.
  49  */
  50 char *
  51 _ldtoa_r(struct _reent *ptr,
  52     long double ld, int mode, int ndigits, int *decpt, int *sign, char **rve)
  53 {
  54         FPI fpi = {
  55                 LDBL_MANT_DIG,                  /* nbits */
  56                 LDBL_MIN_EXP - LDBL_MANT_DIG,   /* emin */
  57                 LDBL_MAX_EXP - LDBL_MANT_DIG,   /* emax */
  58                 FLT_ROUNDS,                     /* rounding */
  59 #ifdef Sudden_Underflow /* unused, but correct anyway */
  60                 1
  61 #else
  62                 0
  63 #endif
  64         };
  65         int be, kind;
  66         char *ret;
  67         struct ieee_ext *p = (struct ieee_ext *)&ld;
  68         uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
  69         void *vbits = bits;
  70
  71         _REENT_CHECK_MP (ptr);
  72
  73         /* reentrancy addition to use mprec storage pool */
  74         if (_REENT_MP_RESULT (ptr)) {
  75                 freedtoa (ptr, (char *) _REENT_MP_RESULT (ptr));
  76                 _REENT_MP_RESULT (ptr) = 0;
  77         }
  78
  79         /*
  80          * gdtoa doesn't know anything about the sign of the number, so
  81          * if the number is negative, we need to swap rounding modes of
  82          * 2 (upwards) and 3 (downwards).
  83          */
  84         *sign = p->ext_sign;
  85         fpi.rounding ^= (fpi.rounding >> 1) & p->ext_sign;
  86
  87         be = p->ext_exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1);
  88         EXT_TO_ARRAY32(p, bits);
  89
  90         switch (fpclassify(ld)) {
  91         case FP_NORMAL:
  92                 kind = STRTOG_Normal;
  93 #ifdef EXT_IMPLICIT_NBIT
  94                 bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
  95 #endif /* EXT_IMPLICIT_NBIT */
  96                 break;
  97         case FP_ZERO:
  98                 kind = STRTOG_Zero;
  99                 break;
 100         case FP_SUBNORMAL:
 101                 kind = STRTOG_Denormal;
 102                 be++;
 103                 break;
 104         case FP_INFINITE:
 105                 kind = STRTOG_Infinite;
 106                 break;
 107         case FP_NAN:
 108                 kind = STRTOG_NaN;
 109                 break;
 110         default:
 111                 abort();
 112         }
 113
 114         ret = gdtoa(ptr, &fpi, be, vbits, &kind, mode, ndigits, decpt, rve);
 115         if (*decpt == -32768)
 116                 *decpt = INT_MAX;
 117         return ret;
 118 }
 119 DEF_STRONG(_ldtoa_r);
 120
 121 #else   /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
 122
 123 char *
 124 _ldtoa_r(struct _reent *ptr,
 125     long double ld, int mode, int ndigits, int *decpt, int *sign,
 126     char **rve)
 127 {
 128         char *ret;
 129
 130         ret = _dtoa_r(ptr, (double)ld, mode, ndigits, decpt, sign, rve);
 131         if (*decpt == 9999)
 132                 *decpt = INT_MAX;
 133         return ret;
 134 }
 135 DEF_STRONG(_ldtoa_r);
 136
 137 #endif  /* (LDBL_MANT_DIG == DBL_MANT_DIG) */
 138
 139 /* Routine used to tell if long double is NaN or Infinity or regular number.
 140    Returns:  0 = regular number
 141              1 = Nan
 142              2 = Infinity
 143 */
 144 int
 145 _ldcheck (long double *d)
 146 {
 147         switch (fpclassify(*d)) {
 148         case FP_NAN:
 149                 return 1;
 150         case FP_INFINITE:
 151                 return 2;
 152         default:
 153                 return 0;
 154         }
 155 }
 156
 157 #endif /* _USE_GDTOA */