/* $NetBSD: strtod.c,v 1.15 2019/08/01 02:27:43 riastradh Exp $ */

/****************************************************************

The author of this software is David M. Gay.

Copyright (C) 1998-2001 by Lucent Technologies
All Rights Reserved

Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of Lucent or any of its entities
not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.

****************************************************************/

/* Please send bug reports to David M. Gay (dmg at acm dot org,
 * with " at " changed at "@" and " dot " changed to ".").	*/

#include "gdtoaimp.h"
#ifndef NO_FENV_H
#include <fenv.h>
#endif

#ifdef USE_LOCALE
#include <locale.h>
#include "setlocale_local.h"
#endif

#ifdef IEEE_Arith
#ifndef NO_IEEE_Scale
#define Avoid_Underflow
#undef tinytens
/* The factor of 2^106 in tinytens[4] helps us avoid setting the underflow */
/* flag unnecessarily.  It leads to a song and dance at the end of strtod. */
static CONST double tinytens[] = {1e-16, 1e-32, 1e-64, 1e-128,
                                  9007199254740992. * 9007199254740992.e-256};
#endif
#endif

#ifdef Honor_FLT_ROUNDS
#undef Check_FLT_ROUNDS
#define Check_FLT_ROUNDS
#else
#define Rounding Flt_Rounds
#endif

#ifdef Avoid_Underflow /*{*/
static double sulp
#ifdef KR_headers
  (x, scale) U *x;
int scale;
#else
  (U *x, int scale)
#endif
{
  U u;
  double rv;
  int i;

  rv = ulp(x);
  if (!scale || (i = 2 * P + 1 - ((word0(x) & Exp_mask) >> Exp_shift)) <= 0)
    return rv; /* Is there an example where i <= 0 ? */
  word0(&u) = Exp_1 + (i << Exp_shift);
  word1(&u) = 0;
  return rv * u.d;
}
#endif /*}*/

static double _int_strtod_l(CONST char *s00, char **se, locale_t loc) {
#ifdef Avoid_Underflow
  int scale;
#endif
#ifdef INFNAN_CHECK
  int decpt;
#endif
  int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign, e, e1, esign, i, j, k, nd,
    nd0, nf, nz, nz0, sign;
  CONST char *s, *s0, *s1;
  double aadj;
  Long L;
  U adj, aadj1, rv, rv0;
  ULong y, z;
  Bigint *bb = NULL, *bb1, *bd0;
  Bigint *bd = NULL, *bs = NULL, *delta = NULL; /* pacify gcc */
#ifdef Avoid_Underflow
  ULong Lsb, Lsb1;
#endif
#ifdef SET_INEXACT
  int inexact, oldinexact;
#endif
#ifdef USE_LOCALE /*{{*/
  char *decimalpoint = localeconv_l(loc)->decimal_point;
  size_t dplen = strlen(decimalpoint);
#endif /*USE_LOCALE}}*/

#ifdef Honor_FLT_ROUNDS /*{*/
  int Rounding;
#ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */
  Rounding = Flt_Rounds;
#else  /*}{*/
  Rounding = 1;
  switch (fegetround()) {
    case FE_TOWARDZERO:
      Rounding = 0;
      break;
    case FE_UPWARD:
      Rounding = 2;
      break;
    case FE_DOWNWARD:
      Rounding = 3;
  }
#endif /*}}*/
#endif /*}*/

#ifdef INFNAN_CHECK
  decpt = 0;
#endif
  sign = nz0 = nz = 0;
  dval(&rv) = 0.;
  for (s = s00;; s++)
    switch (*s) {
      case '-':
        sign = 1;
        /* FALLTHROUGH */
      case '+':
        if (*++s)
          goto break2;
        /* FALLTHROUGH */
      case 0:
        goto ret0;
      case '\t':
      case '\n':
      case '\v':
      case '\f':
      case '\r':
      case ' ':
        continue;
      default:
        goto break2;
    }
break2:
  if (*s == '0') {
#ifndef NO_HEX_FP /*{*/
    {
      static CONST FPI fpi = {53, 1 - 1023 - 53 + 1, 2046 - 1023 - 53 + 1, 1,
                              SI};
      Long expt;
      ULong bits[2];
      switch (s[1]) {
        case 'x':
        case 'X': {
#ifdef Honor_FLT_ROUNDS
          FPI fpi1 = fpi;
          fpi1.rounding = Rounding;
#else
#define fpi1 fpi
#endif
          switch ((i = gethex(&s, &fpi1, &expt, &bb, sign, loc)) &
                  STRTOG_Retmask) {
            case STRTOG_NoNumber:
              s = s00;
              sign = 0;
              /* FALLTHROUGH */
            case STRTOG_Zero:
              break;
            default:
              if (bb) {
                copybits(bits, fpi.nbits, bb);
                Bfree(bb);
              }
              ULtod((/* LINTED */ (U *)&rv)->L, bits, expt, i);
          }
        }
          goto ret;
      }
    }
#endif /*}*/
    nz0 = 1;
    while (*++s == '0')
      ;
    if (!*s)
      goto ret;
  }
  s0 = s;
  y = z = 0;
  for (nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)
    if (nd < 9)
      y = 10 * y + c - '0';
    else if (nd < 16)
      z = 10 * z + c - '0';
  nd0 = nd;
#ifdef USE_LOCALE
  if (c == *decimalpoint) {
    for (i = 1; decimalpoint[i]; ++i)
      if (s[i] != decimalpoint[i])
        goto dig_done;
    s += i;
    c = *s;
#else
  if (c == '.') {
    c = *++s;
#endif
#ifdef INFNAN_CHECK
    decpt = 1;
#endif
    if (!nd) {
      for (; c == '0'; c = *++s)
        nz++;
      if (c > '0' && c <= '9') {
        s0 = s;
        nf += nz;
        nz = 0;
        goto have_dig;
      }
      goto dig_done;
    }
    for (; c >= '0' && c <= '9'; c = *++s) {
    have_dig:
      nz++;
      if (c -= '0') {
        nf += nz;
        for (i = 1; i < nz; i++)
          if (nd++ < 9)
            y *= 10;
          else if (nd <= DBL_DIG + 1)
            z *= 10;
        if (nd++ < 9)
          y = 10 * y + c;
        else if (nd <= DBL_DIG + 1)
          z = 10 * z + c;
        nz = 0;
      }
    }
  } /*}*/
dig_done:
  e = 0;
  if (c == 'e' || c == 'E') {
    if (!nd && !nz && !nz0) {
      goto ret0;
    }
    s00 = s;
    esign = 0;
    switch (c = *++s) {
      case '-':
        esign = 1;
        /* FALLTHROUGH */
      case '+':
        c = *++s;
    }
    if (c >= '0' && c <= '9') {
      while (c == '0')
        c = *++s;
      if (c > '0' && c <= '9') {
        L = c - '0';
        s1 = s;
        while ((c = *++s) >= '0' && c <= '9')
          L = 10 * L + c - '0';
        if (s - s1 > 8 || L > 19999)
          /* Avoid confusion from exponents
           * so large that e might overflow.
           */
          e = 19999; /* safe for 16 bit ints */
        else
          e = (int)L;
        if (esign)
          e = -e;
      } else
        e = 0;
    } else
      s = s00;
  }
  if (!nd) {
    if (!nz && !nz0) {
#ifdef INFNAN_CHECK
      /* Check for Nan and Infinity */
      ULong bits[2];
      static CONST FPI fpinan = /* only 52 explicit bits */
        {52, 1 - 1023 - 53 + 1, 2046 - 1023 - 53 + 1, 1, SI};
      if (!decpt)
        switch (c) {
          case 'i':
          case 'I':
            if (match(&s, "nf")) {
              --s;
              if (!match(&s, "inity"))
                ++s;
              word0(&rv) = 0x7ff00000;
              word1(&rv) = 0;
              goto ret;
            }
            break;
          case 'n':
          case 'N':
            if (match(&s, "an")) {
#ifndef No_Hex_NaN
              if (*s == '(' /*)*/
                  && hexnan(&s, &fpinan, bits) == STRTOG_NaNbits) {
                word0(&rv) = 0x7ff00000 | bits[1];
                word1(&rv) = bits[0];
              } else {
#endif
                word0(&rv) = NAN_WORD0;
                word1(&rv) = NAN_WORD1;
#ifndef No_Hex_NaN
              }
#endif
              goto ret;
            }
        }
#endif /* INFNAN_CHECK */
    ret0:
      s = s00;
      sign = 0;
    }
    goto ret;
  }
  e1 = e -= nf;

  /* Now we have nd0 digits, starting at s0, followed by a
   * decimal point, followed by nd-nd0 digits.  The number we're
   * after is the integer represented by those digits times
   * 10**e */

  if (!nd0)
    nd0 = nd;
  k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;
  dval(&rv) = y;
  if (k > 9) {
#ifdef SET_INEXACT
    if (k > DBL_DIG)
      oldinexact = get_inexact();
#endif
    dval(&rv) = tens[k - 9] * dval(&rv) + z;
  }
  bd0 = 0;
  if (nd <= DBL_DIG
#ifndef RND_PRODQUOT
#ifndef Honor_FLT_ROUNDS
      && Flt_Rounds == 1
#endif
#endif
  ) {
    if (!e)
      goto ret;
#ifndef ROUND_BIASED_without_Round_Up
    if (e > 0) {
      if (e <= Ten_pmax) {
#ifdef VAX
        goto vax_ovfl_check;
#else
#ifdef Honor_FLT_ROUNDS
        /* round correctly FLT_ROUNDS = 2 or 3 */
        if (sign) {
          rv.d = -rv.d;
          sign = 0;
        }
#endif
        /* rv = */ rounded_product(dval(&rv), tens[e]);
        goto ret;
#endif
      }
      i = DBL_DIG - nd;
      if (e <= Ten_pmax + i) {
        /* A fancier test would sometimes let us do
         * this for larger i values.
         */
#ifdef Honor_FLT_ROUNDS
        /* round correctly FLT_ROUNDS = 2 or 3 */
        if (sign) {
          rv.d = -rv.d;
          sign = 0;
        }
#endif
        e -= i;
        dval(&rv) *= tens[i];
#ifdef VAX
        /* VAX exponent range is so narrow we must
         * worry about overflow here...
         */
      vax_ovfl_check:
        word0(&rv) -= P * Exp_msk1;
        /* rv = */ rounded_product(dval(&rv), tens[e]);
        if ((word0(&rv) & Exp_mask) > Exp_msk1 * (DBL_MAX_EXP + Bias - 1 - P))
          goto ovfl;
        word0(&rv) += P * Exp_msk1;
#else
        /* rv = */ rounded_product(dval(&rv), tens[e]);
#endif
        goto ret;
      }
    }
#ifndef Inaccurate_Divide
    else if (e >= -Ten_pmax) {
#ifdef Honor_FLT_ROUNDS
      /* round correctly FLT_ROUNDS = 2 or 3 */
      if (sign) {
        rv.d = -rv.d;
        sign = 0;
      }
#endif
      /* rv = */ rounded_quotient(dval(&rv), tens[-e]);
      goto ret;
    }
#endif
#endif /* ROUND_BIASED_without_Round_Up */
  }
  e1 += nd - k;

#ifdef IEEE_Arith
#ifdef SET_INEXACT
  inexact = 1;
  if (k <= DBL_DIG)
    oldinexact = get_inexact();
#endif
#ifdef Avoid_Underflow
  scale = 0;
#endif
#ifdef Honor_FLT_ROUNDS
  if (Rounding >= 2) {
    if (sign)
      Rounding = Rounding == 2 ? 0 : 2;
    else if (Rounding != 2)
      Rounding = 0;
  }
#endif
#endif /*IEEE_Arith*/

  /* Get starting approximation = rv * 10**e1 */

  if (e1 > 0) {
    if ((i = e1 & 15) != 0)
      dval(&rv) *= tens[i];
    if (e1 &= ~15) {
      if (e1 > DBL_MAX_10_EXP) {
      ovfl:
        /* Can't trust HUGE_VAL */
#ifdef IEEE_Arith
#ifdef Honor_FLT_ROUNDS
        switch (Rounding) {
          case 0: /* toward 0 */
          case 3: /* toward -infinity */
            word0(&rv) = Big0;
            word1(&rv) = Big1;
            break;
          default:
            word0(&rv) = Exp_mask;
            word1(&rv) = 0;
        }
#else  /*Honor_FLT_ROUNDS*/
        word0(&rv) = Exp_mask;
        word1(&rv) = 0;
#endif /*Honor_FLT_ROUNDS*/
#ifdef SET_INEXACT
        /* set overflow bit */
        dval(&rv0) = 1e300;
        dval(&rv0) *= dval(&rv0);
#endif
#else  /*IEEE_Arith*/
        word0(&rv) = Big0;
        word1(&rv) = Big1;
#endif /*IEEE_Arith*/
      range_err:
        if (bd0) {
          Bfree(bb);
          Bfree(bd);
          Bfree(bs);
          Bfree(bd0);
          Bfree(delta);
        }
#ifndef NO_ERRNO
        errno = ERANGE;
#endif
        goto ret;
      }
      e1 = (unsigned int)e1 >> 4;
      for (j = 0; e1 > 1; j++, e1 = (unsigned int)e1 >> 1)
        if (e1 & 1)
          dval(&rv) *= bigtens[j];
      /* The last multiplication could overflow. */
      word0(&rv) -= P * Exp_msk1;
      dval(&rv) *= bigtens[j];
      if ((z = word0(&rv) & Exp_mask) > Exp_msk1 * (DBL_MAX_EXP + Bias - P))
        goto ovfl;
      if (z > Exp_msk1 * (DBL_MAX_EXP + Bias - 1 - P)) {
        /* set to largest number */
        /* (Can't trust DBL_MAX) */
        word0(&rv) = Big0;
        word1(&rv) = Big1;
      } else
        word0(&rv) += P * Exp_msk1;
    }
  } else if (e1 < 0) {
    e1 = -e1;
    if ((i = e1 & 15) != 0)
      dval(&rv) /= tens[i];
    if (e1 >>= 4) {
      if (e1 >= 1 << n_bigtens)
        goto undfl;
#ifdef Avoid_Underflow
      if (e1 & Scale_Bit)
        scale = 2 * P;
      for (j = 0; e1 > 0; j++, e1 = (unsigned int)e1 >> 1)
        if (e1 & 1)
          dval(&rv) *= tinytens[j];
      if (scale &&
          (j = 2 * P + 1 - ((word0(&rv) & Exp_mask) >> Exp_shift)) > 0) {
        /* scaled rv is denormal; zap j low bits */
        if (j >= 32) {
          word1(&rv) = 0;
          if (j >= 53)
            word0(&rv) = (P + 2) * Exp_msk1;
          else
            word0(&rv) &= 0xffffffffU << (j - 32);
        } else
          word1(&rv) &= 0xffffffffU << j;
      }
#else
      for (j = 0; e1 > 1; j++, e1 = (unsigned int)e1 >> 1)
        if (e1 & 1)
          dval(&rv) *= tinytens[j];
      /* The last multiplication could underflow. */
      dval(&rv0) = dval(&rv);
      dval(&rv) *= tinytens[j];
      if (!dval(&rv)) {
        dval(&rv) = 2. * dval(&rv0);
        dval(&rv) *= tinytens[j];
#endif
      if (!dval(&rv)) {
      undfl:
        dval(&rv) = 0.;
        goto range_err;
      }
#ifndef Avoid_Underflow
      word0(&rv) = Tiny0;
      word1(&rv) = Tiny1;
      /* The refinement below will clean
       * this approximation up.
       */
    }
#endif
  }
}

/* Now the hard part -- adjusting rv to the correct value.*/

/* Put digits into bd: true value = bd * 10^e */

bd0 = s2b(s0, nd0, nd, y, dplen);
if (bd0 == NULL)
  goto ovfl;

for (;;) {
  bd = Balloc(bd0->k);
  if (bd == NULL)
    goto ovfl;
  Bcopy(bd, bd0);
  bb = d2b(dval(&rv), &bbe, &bbbits); /* rv = bb * 2^bbe */
  if (bb == NULL)
    goto ovfl;
  bs = i2b(1);
  if (bs == NULL)
    goto ovfl;

  if (e >= 0) {
    bb2 = bb5 = 0;
    bd2 = bd5 = e;
  } else {
    bb2 = bb5 = -e;
    bd2 = bd5 = 0;
  }
  if (bbe >= 0)
    bb2 += bbe;
  else
    bd2 -= bbe;
  bs2 = bb2;
#ifdef Honor_FLT_ROUNDS
  if (Rounding != 1)
    bs2++;
#endif
#ifdef Avoid_Underflow
  Lsb = LSB;
  Lsb1 = 0;
  j = bbe - scale;
  i = j + bbbits - 1; /* logb(rv) */
  j = P + 1 - bbbits;
  if (i < Emin) { /* denormal */
    i = Emin - i;
    j -= i;
    if (i < 32)
      Lsb <<= i;
    else
      Lsb1 = Lsb << (i - 32);
  }
#else /*Avoid_Underflow*/
#ifdef Sudden_Underflow
#ifdef IBM
      j = 1 + 4 * P - 3 - bbbits + ((bbe + bbbits - 1) & 3);
#else
      j = P + 1 - bbbits;
#endif
#else  /*Sudden_Underflow*/
      j = bbe;
      i = j + bbbits - 1; /* logb(&rv) */
      if (i < Emin)       /* denormal */
        j += P - Emin;
      else
        j = P + 1 - bbbits;
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
  bb2 += j;
  bd2 += j;
#ifdef Avoid_Underflow
  bd2 += scale;
#endif
  i = bb2 < bd2 ? bb2 : bd2;
  if (i > bs2)
    i = bs2;
  if (i > 0) {
    bb2 -= i;
    bd2 -= i;
    bs2 -= i;
  }
  if (bb5 > 0) {
    bs = pow5mult(bs, bb5);
    if (bs == NULL)
      goto ovfl;
    bb1 = mult(bs, bb);
    if (bb1 == NULL)
      goto ovfl;
    Bfree(bb);
    bb = bb1;
  }
  if (bb2 > 0) {
    bb = lshift(bb, bb2);
    if (bb == NULL)
      goto ovfl;
  }
  if (bd5 > 0) {
    bd = pow5mult(bd, bd5);
    if (bd == NULL)
      goto ovfl;
  }
  if (bd2 > 0) {
    bd = lshift(bd, bd2);
    if (bd == NULL)
      goto ovfl;
  }
  if (bs2 > 0) {
    bs = lshift(bs, bs2);
    if (bs == NULL)
      goto ovfl;
  }
  delta = diff(bb, bd);
  if (delta == NULL)
    goto ovfl;
  dsign = delta->sign;
  delta->sign = 0;
  i = cmp(delta, bs);
#ifdef Honor_FLT_ROUNDS
  if (Rounding != 1) {
    if (i < 0) {
      /* Error is less than an ulp */
      if (!delta->x[0] && delta->wds <= 1) {
        /* exact */
#ifdef SET_INEXACT
        inexact = 0;
#endif
        break;
      }
      if (Rounding) {
        if (dsign) {
          dval(&adj) = 1.;
          goto apply_adj;
        }
      } else if (!dsign) {
        dval(&adj) = -1.;
        if (!word1(&rv) && !(word0(&rv) & Frac_mask)) {
          y = word0(&rv) & Exp_mask;
#ifdef Avoid_Underflow
          if (!scale || y > 2 * P * Exp_msk1)
#else
          if (y)
#endif
          {
            delta = lshift(delta, Log2P);
            if (cmp(delta, bs) <= 0)
              dval(&adj) = -0.5;
          }
        }
      apply_adj:
#ifdef Avoid_Underflow
        if (scale && (y = word0(&rv) & Exp_mask) <= 2 * P * Exp_msk1)
          word0(&adj) += (2 * P + 1) * Exp_msk1 - y;
#else
#ifdef Sudden_Underflow
        if ((word0(&rv) & Exp_mask) <= P * Exp_msk1) {
          word0(&rv) += P * Exp_msk1;
          dval(&rv) += adj * ulp(&rv);
          word0(&rv) -= P * Exp_msk1;
        } else
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
        dval(&rv) += adj.d * ulp(&rv);
      }
      break;
    }
    dval(&adj) = ratio(delta, bs);
    if (adj.d < 1.)
      dval(&adj) = 1.;
    if (adj.d <= 0x7ffffffe) {
      /* dval(&adj) = Rounding ? ceil(&adj) : floor(&adj); */
      y = adj.d;
      if (y != adj.d) {
        if (!((Rounding >> 1) ^ dsign))
          y++;
        dval(&adj) = y;
      }
    }
#ifdef Avoid_Underflow
    if (scale && (y = word0(&rv) & Exp_mask) <= 2 * P * Exp_msk1)
      word0(&adj) += (2 * P + 1) * Exp_msk1 - y;
#else
#ifdef Sudden_Underflow
    if ((word0(&rv) & Exp_mask) <= P * Exp_msk1) {
      word0(&rv) += P * Exp_msk1;
      dval(&adj) *= ulp(&rv);
      if (dsign)
        dval(&rv) += adj;
      else
        dval(&rv) -= adj;
      word0(&rv) -= P * Exp_msk1;
      goto cont;
    }
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
    dval(&adj) *= ulp(&rv);
    if (dsign) {
      if (word0(&rv) == Big0 && word1(&rv) == Big1)
        goto ovfl;
      dval(&rv) += adj.d;
    } else
      dval(&rv) -= adj.d;
    goto cont;
  }
#endif /*Honor_FLT_ROUNDS*/

  if (i < 0) {
    /* Error is less than half an ulp -- check for
     * special case of mantissa a power of two.
     */
    if (dsign || word1(&rv) || word0(&rv) & Bndry_mask
#ifdef IEEE_Arith
#ifdef Avoid_Underflow
        || (word0(&rv) & Exp_mask) <= (2 * P + 1) * Exp_msk1
#else
        || (word0(&rv) & Exp_mask) <= Exp_msk1
#endif
#endif
    ) {
#ifdef SET_INEXACT
      if (!delta->x[0] && delta->wds <= 1)
        inexact = 0;
#endif
      break;
    }
    if (!delta->x[0] && delta->wds <= 1) {
      /* exact result */
#ifdef SET_INEXACT
      inexact = 0;
#endif
      break;
    }
    delta = lshift(delta, Log2P);
    if (cmp(delta, bs) > 0)
      goto drop_down;
    break;
  }
  if (i == 0) {
    /* exactly half-way between */
    if (dsign) {
      if ((word0(&rv) & Bndry_mask1) == Bndry_mask1 &&
          word1(&rv) ==
            (
#ifdef Avoid_Underflow
              (scale && (y = word0(&rv) & Exp_mask) <= 2 * P * Exp_msk1)
                ? (0xffffffff & (0xffffffff << (2 * P + 1 - (y >> Exp_shift))))
                :
#endif
                0xffffffff)) {
        /*boundary case -- increment exponent*/
        if (word0(&rv) == Big0 && word1(&rv) == Big1)
          goto ovfl;
        word0(&rv) = (word0(&rv) & Exp_mask) + Exp_msk1
#ifdef IBM
                     | Exp_msk1 >> 4
#endif
          ;
        word1(&rv) = 0;
#ifdef Avoid_Underflow
        dsign = 0;
#endif
        break;
      }
    } else if (!(word0(&rv) & Bndry_mask) && !word1(&rv)) {
    drop_down:
      /* boundary case -- decrement exponent */
#ifdef Sudden_Underflow /*{{*/
      L = word0(&rv) & Exp_mask;
#ifdef IBM
      if (L < Exp_msk1)
#else
#ifdef Avoid_Underflow
      if (L <= (scale ? (2 * P + 1) * Exp_msk1 : Exp_msk1))
#else
      if (L <= Exp_msk1)
#endif /*Avoid_Underflow*/
#endif /*IBM*/
        goto undfl;
      L -= Exp_msk1;
#else /*Sudden_Underflow}{*/
#ifdef Avoid_Underflow
          if (scale) {
            L = word0(&rv) & Exp_mask;
            if (L <= (2 * P + 1) * Exp_msk1) {
              if (L > (P + 2) * Exp_msk1)
                /* round even ==> */
                /* accept rv */
                break;
              /* rv = smallest denormal */
              goto undfl;
            }
          }
#endif /*Avoid_Underflow*/
          L = (word0(&rv) & Exp_mask) - Exp_msk1;
#endif /*Sudden_Underflow}}*/
      word0(&rv) = L | Bndry_mask1;
      word1(&rv) = 0xffffffff;
#ifdef IBM
      goto cont;
#else
          break;
#endif
    }
#ifndef ROUND_BIASED
#ifdef Avoid_Underflow
    if (Lsb1) {
      if (!(word0(&rv) & Lsb1))
        break;
    } else if (!(word1(&rv) & Lsb))
      break;
#else
    if (!(word1(&rv) & LSB))
      break;
#endif
#endif
    if (dsign)
#ifdef Avoid_Underflow
      dval(&rv) += sulp(&rv, scale);
#else
          dval(&rv) += ulp(&rv);
#endif
#ifndef ROUND_BIASED
    else {
#ifdef Avoid_Underflow
      dval(&rv) -= sulp(&rv, scale);
#else
      dval(&rv) -= ulp(&rv);
#endif
#ifndef Sudden_Underflow
      if (!dval(&rv))
        goto undfl;
#endif
    }
#ifdef Avoid_Underflow
    dsign = 1 - dsign;
#endif
#endif
    break;
  }
  if ((aadj = ratio(delta, bs)) <= 2.) {
    if (dsign)
      aadj = dval(&aadj1) = 1.;
    else if (word1(&rv) || word0(&rv) & Bndry_mask) {
#ifndef Sudden_Underflow
      if (word1(&rv) == Tiny1 && !word0(&rv))
        goto undfl;
#endif
      aadj = 1.;
      dval(&aadj1) = -1.;
    } else {
      /* special case -- power of FLT_RADIX to be */
      /* rounded down... */

      if (aadj < 2. / FLT_RADIX)
        aadj = 1. / FLT_RADIX;
      else
        aadj *= 0.5;
      dval(&aadj1) = -aadj;
    }
  } else {
    aadj *= 0.5;
    dval(&aadj1) = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
    /* CONSTCOND */
    switch (Rounding) {
      case 2: /* towards +infinity */
        dval(&aadj1) -= 0.5;
        break;
      case 0: /* towards 0 */
      case 3: /* towards -infinity */
        dval(&aadj1) += 0.5;
    }
#else
        /* CONSTCOND */
        if (Flt_Rounds == 0)
          dval(&aadj1) += 0.5;
#endif /*Check_FLT_ROUNDS*/
  }
  y = word0(&rv) & Exp_mask;

  /* Check for overflow */

  if (y == Exp_msk1 * (DBL_MAX_EXP + Bias - 1)) {
    dval(&rv0) = dval(&rv);
    word0(&rv) -= P * Exp_msk1;
    dval(&adj) = dval(&aadj1) * ulp(&rv);
    dval(&rv) += dval(&adj);
    if ((word0(&rv) & Exp_mask) >= Exp_msk1 * (DBL_MAX_EXP + Bias - P)) {
      if (word0(&rv0) == Big0 && word1(&rv0) == Big1)
        goto ovfl;
      word0(&rv) = Big0;
      word1(&rv) = Big1;
      goto cont;
    } else
      word0(&rv) += P * Exp_msk1;
  } else {
#ifdef Avoid_Underflow
    if (scale && y <= 2 * P * Exp_msk1) {
      if (aadj <= 0x7fffffff) {
        if ((z = aadj) == 0)
          z = 1;
        aadj = z;
        dval(&aadj1) = dsign ? aadj : -aadj;
      }
      word0(&aadj1) += (2 * P + 1) * Exp_msk1 - y;
    }
    dval(&adj) = dval(&aadj1) * ulp(&rv);
    dval(&rv) += dval(&adj);
#else
#ifdef Sudden_Underflow
        if ((word0(&rv) & Exp_mask) <= P * Exp_msk1) {
          dval(&rv0) = dval(&rv);
          word0(&rv) += P * Exp_msk1;
          dval(&adj) = dval(&aadj1) * ulp(&rv);
          dval(&rv) += dval(&adj);
#ifdef IBM
          if ((word0(&rv) & Exp_mask) < P * Exp_msk1)
#else
          if ((word0(&rv) & Exp_mask) <= P * Exp_msk1)
#endif
          {
            if (word0(&rv0) == Tiny0 && word1(&rv0) == Tiny1)
              goto undfl;
            word0(&rv) = Tiny0;
            word1(&rv) = Tiny1;
            goto cont;
          } else
            word0(&rv) -= P * Exp_msk1;
        } else {
          dval(&adj) = dval(&aadj1) * ulp(&rv);
          dval(&rv) += dval(&adj);
        }
#else  /*Sudden_Underflow*/
        /* Compute dval(&adj) so that the IEEE rounding rules will
         * correctly round rv + dval(&adj) in some half-way cases.
         * If rv * ulp(&rv) is denormalized (i.e.,
         * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid
         * trouble from bits lost to denormalization;
         * example: 1.2e-307 .
         */
        if (y <= (P - 1) * Exp_msk1 && aadj > 1.) {
          dval(&aadj1) = (double)(int)(aadj + 0.5);
          if (!dsign)
            dval(&aadj1) = -dval(&aadj1);
        }
        dval(&adj) = dval(&aadj1) * ulp(&rv);
        dval(&rv) += adj;
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
  }
  z = word0(&rv) & Exp_mask;
#ifndef SET_INEXACT
#ifdef Avoid_Underflow
  if (!scale)
#endif
    if (y == z) {
      /* Can we stop now? */
      L = (Long)aadj;
      aadj -= L;
      /* The tolerances below are conservative. */
      if (dsign || word1(&rv) || word0(&rv) & Bndry_mask) {
        if (aadj < .4999999 || aadj > .5000001)
          break;
      } else if (aadj < .4999999 / FLT_RADIX)
        break;
    }
#endif
cont:
  Bfree(bb);
  Bfree(bd);
  Bfree(bs);
  Bfree(delta);
}
Bfree(bb);
Bfree(bd);
Bfree(bs);
Bfree(bd0);
Bfree(delta);
#ifdef SET_INEXACT
if (inexact) {
  if (!oldinexact) {
    word0(&rv0) = Exp_1 + (70 << Exp_shift);
    word1(&rv0) = 0;
    dval(&rv0) += 1.;
  }
} else if (!oldinexact)
  clear_inexact();
#endif
#ifdef Avoid_Underflow
if (scale) {
  word0(&rv0) = Exp_1 - 2 * P * Exp_msk1;
  word1(&rv0) = 0;
  dval(&rv) *= dval(&rv0);
#ifndef NO_ERRNO
  /* try to avoid the bug of testing an 8087 register value */
#ifdef IEEE_Arith
  if (!(word0(&rv) & Exp_mask))
#else
  if (word0(&rv) == 0 && word1(&rv) == 0)
#endif
    errno = ERANGE;
#endif
}
#endif /* Avoid_Underflow */
#ifdef SET_INEXACT
if (inexact && !(word0(&rv) & Exp_mask)) {
  /* set underflow bit */
  dval(&rv0) = 1e-300;
  dval(&rv0) *= dval(&rv0);
}
#endif
ret : if (se) *se = __UNCONST(s);
return sign ? -dval(&rv) : dval(&rv);
}

double strtod(CONST char *s, char **sp) {
  return _int_strtod_l(s, sp, _current_locale());
}

#ifdef __SIZEOF_INT128__
long double strtold(CONST char *s, char **sp) {
  return _int_strtod_l(s, sp, _current_locale());
}
#endif

double strtod_l(CONST char *s, char **sp, locale_t loc) {
  return _int_strtod_l(s, sp, loc);
}

#ifdef __SIZEOF_INT128__
long double strtold_l(CONST char *s, char **sp, locale_t loc) {
  return _int_strtod_l(s, sp, loc);
}
#endif
