StdLib/LibC/gdtoa/ldtoa.c

   1 /*  $NetBSD: ldtoa.c,v 1.4.2.1 2007/05/07 19:49:06 pavel Exp $  */
   2
   3 /*-
   4  * Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28 #include  <LibConfig.h>
  29 #include <sys/EfiCdefs.h>
  30
  31 #include <float.h>
  32 #include <inttypes.h>
  33 #include <limits.h>
  34 #include <math.h>
  35 #include <stdlib.h>
  36 #include <machine/ieee.h>
  37 #include "gdtoaimp.h"
  38
  39 #if defined(_MSC_VER)
  40   /*  Disable warnings about conversions to narrower data types,
  41       primarily for the fpclassify() macro.
  42   */
  43   #pragma warning ( disable : 4244 )
  44   // Squelch bogus warnings about uninitialized variable use.
  45   #pragma warning ( disable : 4700 )
  46 #endif
  47
  48 /*
  49  * ldtoa() is a wrapper for gdtoa() that makes it smell like dtoa(),
  50  * except that the floating point argument is passed by reference.
  51  * When dtoa() is passed a NaN or infinity, it sets expt to 9999.
  52  * However, a long double could have a valid exponent of 9999, so we
  53  * use INT_MAX in ldtoa() instead.
  54  */
  55 char *
  56 ldtoa(long double *ld, int mode, int ndigits, int *decpt, int *sign, char **rve)
  57 {
  58 #ifdef EXT_EXPBITS
  59   static FPI fpi = {
  60     LDBL_MANT_DIG,      /* nbits */
  61     LDBL_MIN_EXP - LDBL_MANT_DIG, /* emin */
  62     LDBL_MAX_EXP - LDBL_MANT_DIG, /* emax */
  63     FPI_Round_near,           /* rounding */
  64 #ifdef Sudden_Underflow /* unused, but correct anyway */
  65     1
  66 #else
  67     0
  68 #endif
  69   };
  70   int be, kind;
  71   char *ret;
  72   union ieee_ext_u u;
  73   uint32_t bits[(LDBL_MANT_DIG + 31) / 32];
  74
  75   u.extu_ld = *ld;
  76   *sign = (int)(u.extu_ext.ext_sign);
  77   be = (int)(u.extu_ext.ext_exp - (LDBL_MAX_EXP - 1) - (LDBL_MANT_DIG - 1));
  78   EXT_TO_ARRAY32(u, bits);
  79
  80   switch (fpclassify(u.extu_ld)) {
  81   case FP_NORMAL:
  82     kind = STRTOG_Normal;
  83 #ifdef  LDBL_IMPLICIT_NBIT
  84     bits[LDBL_MANT_DIG / 32] |= 1 << ((LDBL_MANT_DIG - 1) % 32);
  85 #endif /* LDBL_IMPLICIT_NBIT */
  86     break;
  87   case FP_ZERO:
  88     kind = STRTOG_Zero;
  89     break;
  90   case FP_SUBNORMAL:
  91     kind = STRTOG_Denormal;
  92 #ifdef  LDBL_IMPLICIT_NBIT
  93     be++;
  94 #endif
  95     break;
  96   case FP_INFINITE:
  97     kind = STRTOG_Infinite;
  98     break;
  99   case FP_NAN:
 100     kind = STRTOG_NaN;
 101     break;
 102   default:
 103     abort();
 104   }
 105
 106   ret = gdtoa(&fpi, be, (ULong *)bits, &kind, mode, ndigits, decpt, rve);
 107   if (*decpt == -32768)
 108     *decpt = INT_MAX;
 109   return ret;
 110 #else
 111   return dtoa((double)*ld, mode, ndigits, decpt, sign, rve);
 112 #endif
 113 }