Backed out 2 changesets (bug 1943998) for causing wd failures @ phases.py CLOSED...

[gecko.git] / nsprpub / pr / src / misc / prdtoa.c

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * This file is based on the third-party code dtoa.c.  We minimize our
 * modifications to third-party code to make it easy to merge new versions.
 * The author of dtoa.c was not willing to add the parentheses suggested by
 * GCC, so we suppress these warnings.
 */
#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2)
#  pragma GCC diagnostic ignored "-Wparentheses"
#endif

#include "primpl.h"
#include "prbit.h"

#define MULTIPLE_THREADS
#define ACQUIRE_DTOA_LOCK(n) PR_Lock(dtoa_lock[n])
#define FREE_DTOA_LOCK(n) PR_Unlock(dtoa_lock[n])

static PRLock* dtoa_lock[2];

void _PR_InitDtoa(void) {
  dtoa_lock[0] = PR_NewLock();
  dtoa_lock[1] = PR_NewLock();
}

void _PR_CleanupDtoa(void) {
  PR_DestroyLock(dtoa_lock[0]);
  dtoa_lock[0] = NULL;
  PR_DestroyLock(dtoa_lock[1]);
  dtoa_lock[1] = NULL;

  /* FIXME: deal with freelist and p5s. */
}

#if !defined(__ARM_EABI__) && (defined(__arm) || defined(__arm__) || \
                               defined(__arm26__) || defined(__arm32__))
#  define IEEE_ARM
#elif defined(IS_LITTLE_ENDIAN)
#  define IEEE_8087
#else
#  define IEEE_MC68k
#endif

#define Long PRInt32
#define ULong PRUint32
#define NO_LONG_LONG

#define No_Hex_NaN

/****************************************************************
 *
 * The author of this software is David M. Gay.
 *
 * Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 *
 ***************************************************************/

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

/* On a machine with IEEE extended-precision registers, it is
 * necessary to specify double-precision (53-bit) rounding precision
 * before invoking strtod or dtoa.  If the machine uses (the equivalent
 * of) Intel 80x87 arithmetic, the call
 *  _control87(PC_53, MCW_PC);
 * does this with many compilers.  Whether this or another call is
 * appropriate depends on the compiler; for this to work, it may be
 * necessary to #include "float.h" or another system-dependent header
 * file.
 */

/* strtod for IEEE-, VAX-, and IBM-arithmetic machines.
 *
 * This strtod returns a nearest machine number to the input decimal
 * string (or sets errno to ERANGE).  With IEEE arithmetic, ties are
 * broken by the IEEE round-even rule.  Otherwise ties are broken by
 * biased rounding (add half and chop).
 *
 * Inspired loosely by William D. Clinger's paper "How to Read Floating
 * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 92-101].
 *
 * Modifications:
 *
 *  1. We only require IEEE, IBM, or VAX double-precision
 *      arithmetic (not IEEE double-extended).
 *  2. We get by with floating-point arithmetic in a case that
 *      Clinger missed -- when we're computing d * 10^n
 *      for a small integer d and the integer n is not too
 *      much larger than 22 (the maximum integer k for which
 *      we can represent 10^k exactly), we may be able to
 *      compute (d*10^k) * 10^(e-k) with just one roundoff.
 *  3. Rather than a bit-at-a-time adjustment of the binary
 *      result in the hard case, we use floating-point
 *      arithmetic to determine the adjustment to within
 *      one bit; only in really hard cases do we need to
 *      compute a second residual.
 *  4. Because of 3., we don't need a large table of powers of 10
 *      for ten-to-e (just some small tables, e.g. of 10^k
 *      for 0 <= k <= 22).
 */

/*
 * #define IEEE_8087 for IEEE-arithmetic machines where the least
 *  significant byte has the lowest address.
 * #define IEEE_MC68k for IEEE-arithmetic machines where the most
 *  significant byte has the lowest address.
 * #define IEEE_ARM for IEEE-arithmetic machines where the two words
 *  in a double are stored in big endian order but the two shorts
 *  in a word are still stored in little endian order.
 * #define Long int on machines with 32-bit ints and 64-bit longs.
 * #define IBM for IBM mainframe-style floating-point arithmetic.
 * #define VAX for VAX-style floating-point arithmetic (D_floating).
 * #define No_leftright to omit left-right logic in fast floating-point
 *  computation of dtoa.
 * #define Honor_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
 *  and strtod and dtoa should round accordingly.
 * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3
 *  and Honor_FLT_ROUNDS is not #defined.
 * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines
 *  that use extended-precision instructions to compute rounded
 *  products and quotients) with IBM.
 * #define ROUND_BIASED for IEEE-format with biased rounding.
 * #define Inaccurate_Divide for IEEE-format with correctly rounded
 *  products but inaccurate quotients, e.g., for Intel i860.
 * #define NO_LONG_LONG on machines that do not have a "long long"
 *  integer type (of >= 64 bits).  On such machines, you can
 *  #define Just_16 to store 16 bits per 32-bit Long when doing
 *  high-precision integer arithmetic.  Whether this speeds things
 *  up or slows things down depends on the machine and the number
 *  being converted.  If long long is available and the name is
 *  something other than "long long", #define Llong to be the name,
 *  and if "unsigned Llong" does not work as an unsigned version of
 *  Llong, #define #ULLong to be the corresponding unsigned type.
 * #define KR_headers for old-style C function headers.
 * #define Bad_float_h if your system lacks a float.h or if it does not
 *  define some or all of DBL_DIG, DBL_MAX_10_EXP, DBL_MAX_EXP,
 *  FLT_RADIX, FLT_ROUNDS, and DBL_MAX.
 * #define MALLOC your_malloc, where your_malloc(n) acts like malloc(n)
 *  if memory is available and otherwise does something you deem
 *  appropriate.  If MALLOC is undefined, malloc will be invoked
 *  directly -- and assumed always to succeed.  Similarly, if you
 *  want something other than the system's free() to be called to
 *  recycle memory acquired from MALLOC, #define FREE to be the
 *  name of the alternate routine.  (FREE or free is only called in
 *  pathological cases, e.g., in a dtoa call after a dtoa return in
 *  mode 3 with thousands of digits requested.)
 * #define Omit_Private_Memory to omit logic (added Jan. 1998) for making
 *  memory allocations from a private pool of memory when possible.
 *  When used, the private pool is PRIVATE_MEM bytes long:  2304 bytes,
 *  unless #defined to be a different length.  This default length
 *  suffices to get rid of MALLOC calls except for unusual cases,
 *  such as decimal-to-binary conversion of a very long string of
 *  digits.  The longest string dtoa can return is about 751 bytes
 *  long.  For conversions by strtod of strings of 800 digits and
 *  all dtoa conversions in single-threaded executions with 8-byte
 *  pointers, PRIVATE_MEM >= 7400 appears to suffice; with 4-byte
 *  pointers, PRIVATE_MEM >= 7112 appears adequate.
 * #define INFNAN_CHECK on IEEE systems to cause strtod to check for
 *  Infinity and NaN (case insensitively).  On some systems (e.g.,
 *  some HP systems), it may be necessary to #define NAN_WORD0
 *  appropriately -- to the most significant word of a quiet NaN.
 *  (On HP Series 700/800 machines, -DNAN_WORD0=0x7ff40000 works.)
 *  When INFNAN_CHECK is #defined and No_Hex_NaN is not #defined,
 *  strtod also accepts (case insensitively) strings of the form
 *  NaN(x), where x is a string of hexadecimal digits and spaces;
 *  if there is only one string of hexadecimal digits, it is taken
 *  for the 52 fraction bits of the resulting NaN; if there are two
 *  or more strings of hex digits, the first is for the high 20 bits,
 *  the second and subsequent for the low 32 bits, with intervening
 *  white space ignored; but if this results in none of the 52
 *  fraction bits being on (an IEEE Infinity symbol), then NAN_WORD0
 *  and NAN_WORD1 are used instead.
 * #define MULTIPLE_THREADS if the system offers preemptively scheduled
 *  multiple threads.  In this case, you must provide (or suitably
 *  #define) two locks, acquired by ACQUIRE_DTOA_LOCK(n) and freed
 *  by FREE_DTOA_LOCK(n) for n = 0 or 1.  (The second lock, accessed
 *  in pow5mult, ensures lazy evaluation of only one copy of high
 *  powers of 5; omitting this lock would introduce a small
 *  probability of wasting memory, but would otherwise be harmless.)
 *  You must also invoke freedtoa(s) to free the value s returned by
 *  dtoa.  You may do so whether or not MULTIPLE_THREADS is #defined.
 * #define NO_IEEE_Scale to disable new (Feb. 1997) logic in strtod that
 *  avoids underflows on inputs whose result does not underflow.
 *  If you #define NO_IEEE_Scale on a machine that uses IEEE-format
 *  floating-point numbers and flushes underflows to zero rather
 *  than implementing gradual underflow, then you must also #define
 *  Sudden_Underflow.
 * #define USE_LOCALE to use the current locale's decimal_point value.
 * #define SET_INEXACT if IEEE arithmetic is being used and extra
 *  computation should be done to set the inexact flag when the
 *  result is inexact and avoid setting inexact when the result
 *  is exact.  In this case, dtoa.c must be compiled in
 *  an environment, perhaps provided by #include "dtoa.c" in a
 *  suitable wrapper, that defines two functions,
 *      int get_inexact(void);
 *      void clear_inexact(void);
 *  such that get_inexact() returns a nonzero value if the
 *  inexact bit is already set, and clear_inexact() sets the
 *  inexact bit to 0.  When SET_INEXACT is #defined, strtod
 *  also does extra computations to set the underflow and overflow
 *  flags when appropriate (i.e., when the result is tiny and
 *  inexact or when it is a numeric value rounded to +-infinity).
 * #define NO_ERRNO if strtod should not assign errno = ERANGE when
 *  the result overflows to +-Infinity or underflows to 0.
 */

#ifndef Long
#  define Long long
#endif
#ifndef ULong
typedef unsigned Long ULong;
#endif

#ifdef DEBUG
#  include "stdio.h"
#  define Bug(x)                  \
    {                             \
      fprintf(stderr, "%s\n", x); \
      exit(1);                    \
    }
#endif

#include "stdlib.h"
#include "string.h"

#ifdef USE_LOCALE
#  include "locale.h"
#endif

#ifdef MALLOC
#  ifdef KR_headers
extern char* MALLOC();
#  else
extern void* MALLOC(size_t);
#  endif
#else
#  define MALLOC malloc
#endif

#ifndef Omit_Private_Memory
#  ifndef PRIVATE_MEM
#    define PRIVATE_MEM 2304
#  endif
#  define PRIVATE_mem ((PRIVATE_MEM + sizeof(double) - 1) / sizeof(double))
static double private_mem[PRIVATE_mem], *pmem_next = private_mem;
#endif

#undef IEEE_Arith
#undef Avoid_Underflow
#ifdef IEEE_MC68k
#  define IEEE_Arith
#endif
#ifdef IEEE_8087
#  define IEEE_Arith
#endif
#ifdef IEEE_ARM
#  define IEEE_Arith
#endif

#include "errno.h"

#ifdef Bad_float_h

#  ifdef IEEE_Arith
#    define DBL_DIG 15
#    define DBL_MAX_10_EXP 308
#    define DBL_MAX_EXP 1024
#    define FLT_RADIX 2
#  endif /*IEEE_Arith*/

#  ifdef IBM
#    define DBL_DIG 16
#    define DBL_MAX_10_EXP 75
#    define DBL_MAX_EXP 63
#    define FLT_RADIX 16
#    define DBL_MAX 7.2370055773322621e+75
#  endif

#  ifdef VAX
#    define DBL_DIG 16
#    define DBL_MAX_10_EXP 38
#    define DBL_MAX_EXP 127
#    define FLT_RADIX 2
#    define DBL_MAX 1.7014118346046923e+38
#  endif

#  ifndef LONG_MAX
#    define LONG_MAX 2147483647
#  endif

#else /* ifndef Bad_float_h */
#  include "float.h"
#endif /* Bad_float_h */

#ifndef __MATH_H__
#  include "math.h"
#endif

#ifdef __cplusplus
extern "C" {
#endif

#ifndef CONST
#  ifdef KR_headers
#    define CONST /* blank */
#  else
#    define CONST const
#  endif
#endif

#if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(IEEE_ARM) + \
        defined(VAX) + defined(IBM) !=                             \
    1
Exactly one of IEEE_8087, IEEE_MC68k, IEEE_ARM, VAX, or IBM should be defined.
#endif

                                                         typedef union {
  double d;
  ULong L[2];
} U;

#define dval(x) (x).d
#ifdef IEEE_8087
#  define word0(x) (x).L[1]
#  define word1(x) (x).L[0]
#else
#  define word0(x) (x).L[0]
#  define word1(x) (x).L[1]
#endif

/* The following definition of Storeinc is appropriate for MIPS processors.
 * An alternative that might be better on some machines is
 * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff)
 */
#if defined(IEEE_8087) + defined(IEEE_ARM) + defined(VAX)
#  define Storeinc(a, b, c)                       \
    (((unsigned short*)a)[1] = (unsigned short)b, \
     ((unsigned short*)a)[0] = (unsigned short)c, a++)
#else
#  define Storeinc(a, b, c)                       \
    (((unsigned short*)a)[0] = (unsigned short)b, \
     ((unsigned short*)a)[1] = (unsigned short)c, a++)
#endif

/* #define P DBL_MANT_DIG */
/* Ten_pmax = floor(P*log(2)/log(5)) */
/* Bletch = (highest power of 2 < DBL_MAX_10_EXP) / 16 */
/* Quick_max = floor((P-1)*log(FLT_RADIX)/log(10) - 1) */
/* Int_max = floor(P*log(FLT_RADIX)/log(10) - 1) */

#ifdef IEEE_Arith
#  define Exp_shift 20
#  define Exp_shift1 20
#  define Exp_msk1 0x100000
#  define Exp_msk11 0x100000
#  define Exp_mask 0x7ff00000
#  define P 53
#  define Bias 1023
#  define Emin (-1022)
#  define Exp_1 0x3ff00000
#  define Exp_11 0x3ff00000
#  define Ebits 11
#  define Frac_mask 0xfffff
#  define Frac_mask1 0xfffff
#  define Ten_pmax 22
#  define Bletch 0x10
#  define Bndry_mask 0xfffff
#  define Bndry_mask1 0xfffff
#  define LSB 1
#  define Sign_bit 0x80000000
#  define Log2P 1
#  define Tiny0 0
#  define Tiny1 1
#  define Quick_max 14
#  define Int_max 14
#  ifndef NO_IEEE_Scale
#    define Avoid_Underflow
#    ifdef Flush_Denorm /* debugging option */
#      undef Sudden_Underflow
#    endif
#  endif

#  ifndef Flt_Rounds
#    ifdef FLT_ROUNDS
#      define Flt_Rounds FLT_ROUNDS
#    else
#      define Flt_Rounds 1
#    endif
#  endif /*Flt_Rounds*/

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

#else /* ifndef IEEE_Arith */
#  undef Check_FLT_ROUNDS
#  undef Honor_FLT_ROUNDS
#  undef SET_INEXACT
#  undef Sudden_Underflow
#  define Sudden_Underflow
#  ifdef IBM
#    undef Flt_Rounds
#    define Flt_Rounds 0
#    define Exp_shift 24
#    define Exp_shift1 24
#    define Exp_msk1 0x1000000
#    define Exp_msk11 0x1000000
#    define Exp_mask 0x7f000000
#    define P 14
#    define Bias 65
#    define Exp_1 0x41000000
#    define Exp_11 0x41000000
#    define Ebits 8 /* exponent has 7 bits, but 8 is the right value in b2d */
#    define Frac_mask 0xffffff
#    define Frac_mask1 0xffffff
#    define Bletch 4
#    define Ten_pmax 22
#    define Bndry_mask 0xefffff
#    define Bndry_mask1 0xffffff
#    define LSB 1
#    define Sign_bit 0x80000000
#    define Log2P 4
#    define Tiny0 0x100000
#    define Tiny1 0
#    define Quick_max 14
#    define Int_max 15
#  else /* VAX */
#    undef Flt_Rounds
#    define Flt_Rounds 1
#    define Exp_shift 23
#    define Exp_shift1 7
#    define Exp_msk1 0x80
#    define Exp_msk11 0x800000
#    define Exp_mask 0x7f80
#    define P 56
#    define Bias 129
#    define Exp_1 0x40800000
#    define Exp_11 0x4080
#    define Ebits 8
#    define Frac_mask 0x7fffff
#    define Frac_mask1 0xffff007f
#    define Ten_pmax 24
#    define Bletch 2
#    define Bndry_mask 0xffff007f
#    define Bndry_mask1 0xffff007f
#    define LSB 0x10000
#    define Sign_bit 0x8000
#    define Log2P 1
#    define Tiny0 0x80
#    define Tiny1 0
#    define Quick_max 15
#    define Int_max 15
#  endif /* IBM, VAX */
#endif   /* IEEE_Arith */

#ifndef IEEE_Arith
#  define ROUND_BIASED
#endif

#ifdef RND_PRODQUOT
#  define rounded_product(a, b) a = rnd_prod(a, b)
#  define rounded_quotient(a, b) a = rnd_quot(a, b)
#  ifdef KR_headers
extern double rnd_prod(), rnd_quot();
#  else
extern double rnd_prod(double, double), rnd_quot(double, double);
#  endif
#else
#  define rounded_product(a, b) a *= b
#  define rounded_quotient(a, b) a /= b
#endif

#define Big0 (Frac_mask1 | Exp_msk1 * (DBL_MAX_EXP + Bias - 1))
#define Big1 0xffffffff

#ifndef Pack_32
#  define Pack_32
#endif

#ifdef KR_headers
#  define FFFFFFFF ((((unsigned long)0xffff) << 16) | (unsigned long)0xffff)
#else
#  define FFFFFFFF 0xffffffffUL
#endif

#ifdef NO_LONG_LONG
#  undef ULLong
#  ifdef Just_16
#    undef Pack_32
/* When Pack_32 is not defined, we store 16 bits per 32-bit Long.
 * This makes some inner loops simpler and sometimes saves work
 * during multiplications, but it often seems to make things slightly
 * slower.  Hence the default is now to store 32 bits per Long.
 */
#  endif
#else /* long long available */
#  ifndef Llong
#    define Llong long long
#  endif
#  ifndef ULLong
#    define ULLong unsigned Llong
#  endif
#endif /* NO_LONG_LONG */

#ifndef MULTIPLE_THREADS
#  define ACQUIRE_DTOA_LOCK(n) /*nothing*/
#  define FREE_DTOA_LOCK(n)    /*nothing*/
#endif

#define Kmax 7

struct Bigint {
  struct Bigint* next;
  int k, maxwds, sign, wds;
  ULong x[1];
};

typedef struct Bigint Bigint;

static Bigint* freelist[Kmax + 1];

static Bigint* Balloc
#ifdef KR_headers
    (k) int k;
#else
    (int k)
#endif
{
  int x;
  Bigint* rv;
#ifndef Omit_Private_Memory
  unsigned int len;
#endif

  ACQUIRE_DTOA_LOCK(0);
  /* The k > Kmax case does not need ACQUIRE_DTOA_LOCK(0), */
  /* but this case seems very unlikely. */
  if (k <= Kmax && (rv = freelist[k])) {
    freelist[k] = rv->next;
  } else {
    x = 1 << k;
#ifdef Omit_Private_Memory
    rv = (Bigint*)MALLOC(sizeof(Bigint) + (x - 1) * sizeof(ULong));
#else
    len = (sizeof(Bigint) + (x - 1) * sizeof(ULong) + sizeof(double) - 1) /
          sizeof(double);
    if (k <= Kmax && pmem_next - private_mem + len <= PRIVATE_mem) {
      rv = (Bigint*)pmem_next;
      pmem_next += len;
    } else {
      rv = (Bigint*)MALLOC(len * sizeof(double));
    }
#endif
    rv->k = k;
    rv->maxwds = x;
  }
  FREE_DTOA_LOCK(0);
  rv->sign = rv->wds = 0;
  return rv;
}

static void Bfree
#ifdef KR_headers
    (v) Bigint* v;
#else
    (Bigint* v)
#endif
{
  if (v) {
    if (v->k > Kmax)
#ifdef FREE
      FREE((void*)v);
#else
      free((void*)v);
#endif
    else {
      ACQUIRE_DTOA_LOCK(0);
      v->next = freelist[v->k];
      freelist[v->k] = v;
      FREE_DTOA_LOCK(0);
    }
  }
}

#define Bcopy(x, y)                        \
  memcpy((char*)&x->sign, (char*)&y->sign, \
         y->wds * sizeof(Long) + 2 * sizeof(int))

static Bigint* multadd
#ifdef KR_headers
    (b, m, a) Bigint* b;
int m, a;
#else
    (Bigint* b, int m, int a) /* multiply by m and add a */
#endif
{
  int i, wds;
#ifdef ULLong
  ULong* x;
  ULLong carry, y;
#else
  ULong carry, *x, y;
#  ifdef Pack_32
  ULong xi, z;
#  endif
#endif
  Bigint* b1;

  wds = b->wds;
  x = b->x;
  i = 0;
  carry = a;
  do {
#ifdef ULLong
    y = *x * (ULLong)m + carry;
    carry = y >> 32;
    *x++ = y & FFFFFFFF;
#else
#  ifdef Pack_32
    xi = *x;
    y = (xi & 0xffff) * m + carry;
    z = (xi >> 16) * m + (y >> 16);
    carry = z >> 16;
    *x++ = (z << 16) + (y & 0xffff);
#  else
    y = *x * m + carry;
    carry = y >> 16;
    *x++ = y & 0xffff;
#  endif
#endif
  } while (++i < wds);
  if (carry) {
    if (wds >= b->maxwds) {
      b1 = Balloc(b->k + 1);
      Bcopy(b1, b);
      Bfree(b);
      b = b1;
    }
    b->x[wds++] = carry;
    b->wds = wds;
  }
  return b;
}

static Bigint* s2b
#ifdef KR_headers
    (s, nd0, nd, y9) CONST char* s;
int nd0, nd;
ULong y9;
#else
    (CONST char* s, int nd0, int nd, ULong y9)
#endif
{
  Bigint* b;
  int i, k;
  Long x, y;

  x = (nd + 8) / 9;
  for (k = 0, y = 1; x > y; y <<= 1, k++);
#ifdef Pack_32
  b = Balloc(k);
  b->x[0] = y9;
  b->wds = 1;
#else
  b = Balloc(k + 1);
  b->x[0] = y9 & 0xffff;
  b->wds = (b->x[1] = y9 >> 16) ? 2 : 1;
#endif

  i = 9;
  if (9 < nd0) {
    s += 9;
    do {
      b = multadd(b, 10, *s++ - '0');
    } while (++i < nd0);
    s++;
  } else {
    s += 10;
  }
  for (; i < nd; i++) {
    b = multadd(b, 10, *s++ - '0');
  }
  return b;
}

static int hi0bits
#ifdef KR_headers
    (x) register ULong x;
#else
    (register ULong x)
#endif
{
#ifdef PR_HAVE_BUILTIN_BITSCAN32
  return ((!x) ? 32 : pr_bitscan_clz32(x));
#else
  register int k = 0;

  if (!(x & 0xffff0000)) {
    k = 16;
    x <<= 16;
  }
  if (!(x & 0xff000000)) {
    k += 8;
    x <<= 8;
  }
  if (!(x & 0xf0000000)) {
    k += 4;
    x <<= 4;
  }
  if (!(x & 0xc0000000)) {
    k += 2;
    x <<= 2;
  }
  if (!(x & 0x80000000)) {
    k++;
    if (!(x & 0x40000000)) {
      return 32;
    }
  }
  return k;
#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
}

static int lo0bits
#ifdef KR_headers
    (y) ULong* y;
#else
    (ULong* y)
#endif
{
#ifdef PR_HAVE_BUILTIN_BITSCAN32
  int k;
  ULong x = *y;

  if (x > 1) {
    *y = (x >> (k = pr_bitscan_ctz32(x)));
  } else {
    k = ((x ^ 1) << 5);
  }
#else
  register int k;
  register ULong x = *y;

  if (x & 7) {
    if (x & 1) {
      return 0;
    }
    if (x & 2) {
      *y = x >> 1;
      return 1;
    }
    *y = x >> 2;
    return 2;
  }
  k = 0;
  if (!(x & 0xffff)) {
    k = 16;
    x >>= 16;
  }
  if (!(x & 0xff)) {
    k += 8;
    x >>= 8;
  }
  if (!(x & 0xf)) {
    k += 4;
    x >>= 4;
  }
  if (!(x & 0x3)) {
    k += 2;
    x >>= 2;
  }
  if (!(x & 1)) {
    k++;
    x >>= 1;
    if (!x) {
      return 32;
    }
  }
  *y = x;
#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
  return k;
}

static Bigint* i2b
#ifdef KR_headers
    (i) int i;
#else
    (int i)
#endif
{
  Bigint* b;

  b = Balloc(1);
  b->x[0] = i;
  b->wds = 1;
  return b;
}

static Bigint *mult
#ifdef KR_headers
    (a, b) Bigint *a,
    *b;
#else
    (Bigint* a, Bigint* b)
#endif
{
  Bigint* c;
  int k, wa, wb, wc;
  ULong *x, *xa, *xae, *xb, *xbe, *xc, *xc0;
  ULong y;
#ifdef ULLong
  ULLong carry, z;
#else
  ULong carry, z;
#  ifdef Pack_32
  ULong z2;
#  endif
#endif

  if (a->wds < b->wds) {
    c = a;
    a = b;
    b = c;
  }
  k = a->k;
  wa = a->wds;
  wb = b->wds;
  wc = wa + wb;
  if (wc > a->maxwds) {
    k++;
  }
  c = Balloc(k);
  for (x = c->x, xa = x + wc; x < xa; x++) {
    *x = 0;
  }
  xa = a->x;
  xae = xa + wa;
  xb = b->x;
  xbe = xb + wb;
  xc0 = c->x;
#ifdef ULLong
  for (; xb < xbe; xc0++) {
    if (y = *xb++) {
      x = xa;
      xc = xc0;
      carry = 0;
      do {
        z = *x++ * (ULLong)y + *xc + carry;
        carry = z >> 32;
        *xc++ = z & FFFFFFFF;
      } while (x < xae);
      *xc = carry;
    }
  }
#else
#  ifdef Pack_32
  for (; xb < xbe; xb++, xc0++) {
    if (y = *xb & 0xffff) {
      x = xa;
      xc = xc0;
      carry = 0;
      do {
        z = (*x & 0xffff) * y + (*xc & 0xffff) + carry;
        carry = z >> 16;
        z2 = (*x++ >> 16) * y + (*xc >> 16) + carry;
        carry = z2 >> 16;
        Storeinc(xc, z2, z);
      } while (x < xae);
      *xc = carry;
    }
    if (y = *xb >> 16) {
      x = xa;
      xc = xc0;
      carry = 0;
      z2 = *xc;
      do {
        z = (*x & 0xffff) * y + (*xc >> 16) + carry;
        carry = z >> 16;
        Storeinc(xc, z, z2);
        z2 = (*x++ >> 16) * y + (*xc & 0xffff) + carry;
        carry = z2 >> 16;
      } while (x < xae);
      *xc = z2;
    }
  }
#  else
  for (; xb < xbe; xc0++) {
    if (y = *xb++) {
      x = xa;
      xc = xc0;
      carry = 0;
      do {
        z = *x++ * y + *xc + carry;
        carry = z >> 16;
        *xc++ = z & 0xffff;
      } while (x < xae);
      *xc = carry;
    }
  }
#  endif
#endif
  for (xc0 = c->x, xc = xc0 + wc; wc > 0 && !*--xc; --wc);
  c->wds = wc;
  return c;
}

static Bigint* p5s;

static Bigint* pow5mult
#ifdef KR_headers
    (b, k) Bigint* b;
int k;
#else
    (Bigint* b, int k)
#endif
{
  Bigint *b1, *p5, *p51;
  int i;
  static int p05[3] = {5, 25, 125};

  if (i = k & 3) {
    b = multadd(b, p05[i - 1], 0);
  }

  if (!(k >>= 2)) {
    return b;
  }
  if (!(p5 = p5s)) {
    /* first time */
#ifdef MULTIPLE_THREADS
    ACQUIRE_DTOA_LOCK(1);
    if (!(p5 = p5s)) {
      p5 = p5s = i2b(625);
      p5->next = 0;
    }
    FREE_DTOA_LOCK(1);
#else
    p5 = p5s = i2b(625);
    p5->next = 0;
#endif
  }
  for (;;) {
    if (k & 1) {
      b1 = mult(b, p5);
      Bfree(b);
      b = b1;
    }
    if (!(k >>= 1)) {
      break;
    }
    if (!(p51 = p5->next)) {
#ifdef MULTIPLE_THREADS
      ACQUIRE_DTOA_LOCK(1);
      if (!(p51 = p5->next)) {
        p51 = p5->next = mult(p5, p5);
        p51->next = 0;
      }
      FREE_DTOA_LOCK(1);
#else
      p51 = p5->next = mult(p5, p5);
      p51->next = 0;
#endif
    }
    p5 = p51;
  }
  return b;
}

static Bigint* lshift
#ifdef KR_headers
    (b, k) Bigint* b;
int k;
#else
    (Bigint* b, int k)
#endif
{
  int i, k1, n, n1;
  Bigint* b1;
  ULong *x, *x1, *xe, z;

#ifdef Pack_32
  n = k >> 5;
#else
  n = k >> 4;
#endif
  k1 = b->k;
  n1 = n + b->wds + 1;
  for (i = b->maxwds; n1 > i; i <<= 1) {
    k1++;
  }
  b1 = Balloc(k1);
  x1 = b1->x;
  for (i = 0; i < n; i++) {
    *x1++ = 0;
  }
  x = b->x;
  xe = x + b->wds;
#ifdef Pack_32
  if (k &= 0x1f) {
    k1 = 32 - k;
    z = 0;
    do {
      *x1++ = *x << k | z;
      z = *x++ >> k1;
    } while (x < xe);
    if (*x1 = z) {
      ++n1;
    }
  }
#else
  if (k &= 0xf) {
    k1 = 16 - k;
    z = 0;
    do {
      *x1++ = *x << k & 0xffff | z;
      z = *x++ >> k1;
    } while (x < xe);
    if (*x1 = z) {
      ++n1;
    }
  }
#endif
  else
    do {
      *x1++ = *x++;
    } while (x < xe);
  b1->wds = n1 - 1;
  Bfree(b);
  return b1;
}

static int cmp
#ifdef KR_headers
    (a, b) Bigint *a,
    *b;
#else
    (Bigint* a, Bigint* b)
#endif
{
  ULong *xa, *xa0, *xb, *xb0;
  int i, j;

  i = a->wds;
  j = b->wds;
#ifdef DEBUG
  if (i > 1 && !a->x[i - 1]) {
    Bug("cmp called with a->x[a->wds-1] == 0");
  }
  if (j > 1 && !b->x[j - 1]) {
    Bug("cmp called with b->x[b->wds-1] == 0");
  }
#endif
  if (i -= j) {
    return i;
  }
  xa0 = a->x;
  xa = xa0 + j;
  xb0 = b->x;
  xb = xb0 + j;
  for (;;) {
    if (*--xa != *--xb) {
      return *xa < *xb ? -1 : 1;
    }
    if (xa <= xa0) {
      break;
    }
  }
  return 0;
}

static Bigint *diff
#ifdef KR_headers
    (a, b) Bigint *a,
    *b;
#else
    (Bigint* a, Bigint* b)
#endif
{
  Bigint* c;
  int i, wa, wb;
  ULong *xa, *xae, *xb, *xbe, *xc;
#ifdef ULLong
  ULLong borrow, y;
#else
  ULong borrow, y;
#  ifdef Pack_32
  ULong z;
#  endif
#endif

  i = cmp(a, b);
  if (!i) {
    c = Balloc(0);
    c->wds = 1;
    c->x[0] = 0;
    return c;
  }
  if (i < 0) {
    c = a;
    a = b;
    b = c;
    i = 1;
  } else {
    i = 0;
  }
  c = Balloc(a->k);
  c->sign = i;
  wa = a->wds;
  xa = a->x;
  xae = xa + wa;
  wb = b->wds;
  xb = b->x;
  xbe = xb + wb;
  xc = c->x;
  borrow = 0;
#ifdef ULLong
  do {
    y = (ULLong)*xa++ - *xb++ - borrow;
    borrow = y >> 32 & (ULong)1;
    *xc++ = y & FFFFFFFF;
  } while (xb < xbe);
  while (xa < xae) {
    y = *xa++ - borrow;
    borrow = y >> 32 & (ULong)1;
    *xc++ = y & FFFFFFFF;
  }
#else
#  ifdef Pack_32
  do {
    y = (*xa & 0xffff) - (*xb & 0xffff) - borrow;
    borrow = (y & 0x10000) >> 16;
    z = (*xa++ >> 16) - (*xb++ >> 16) - borrow;
    borrow = (z & 0x10000) >> 16;
    Storeinc(xc, z, y);
  } while (xb < xbe);
  while (xa < xae) {
    y = (*xa & 0xffff) - borrow;
    borrow = (y & 0x10000) >> 16;
    z = (*xa++ >> 16) - borrow;
    borrow = (z & 0x10000) >> 16;
    Storeinc(xc, z, y);
  }
#  else
  do {
    y = *xa++ - *xb++ - borrow;
    borrow = (y & 0x10000) >> 16;
    *xc++ = y & 0xffff;
  } while (xb < xbe);
  while (xa < xae) {
    y = *xa++ - borrow;
    borrow = (y & 0x10000) >> 16;
    *xc++ = y & 0xffff;
  }
#  endif
#endif
  while (!*--xc) {
    wa--;
  }
  c->wds = wa;
  return c;
}

static double ulp
#ifdef KR_headers
    (dx) double dx;
#else
    (double dx)
#endif
{
  register Long L;
  U x, a;

  dval(x) = dx;
  L = (word0(x) & Exp_mask) - (P - 1) * Exp_msk1;
#ifndef Avoid_Underflow
#  ifndef Sudden_Underflow
  if (L > 0) {
#  endif
#endif
#ifdef IBM
    L |= Exp_msk1 >> 4;
#endif
    word0(a) = L;
    word1(a) = 0;
#ifndef Avoid_Underflow
#  ifndef Sudden_Underflow
  } else {
    L = -L >> Exp_shift;
    if (L < Exp_shift) {
      word0(a) = 0x80000 >> L;
      word1(a) = 0;
    } else {
      word0(a) = 0;
      L -= Exp_shift;
      word1(a) = L >= 31 ? 1 : 1 << 31 - L;
    }
  }
#  endif
#endif
  return dval(a);
}

static double b2d
#ifdef KR_headers
    (a, e) Bigint* a;
int* e;
#else
    (Bigint* a, int* e)
#endif
{
  ULong *xa, *xa0, w, y, z;
  int k;
  U d;
#ifdef VAX
  ULong d0, d1;
#else
#  define d0 word0(d)
#  define d1 word1(d)
#endif

  xa0 = a->x;
  xa = xa0 + a->wds;
  y = *--xa;
#ifdef DEBUG
  if (!y) {
    Bug("zero y in b2d");
  }
#endif
  k = hi0bits(y);
  *e = 32 - k;
#ifdef Pack_32
  if (k < Ebits) {
    d0 = Exp_1 | y >> Ebits - k;
    w = xa > xa0 ? *--xa : 0;
    d1 = y << (32 - Ebits) + k | w >> Ebits - k;
    goto ret_d;
  }
  z = xa > xa0 ? *--xa : 0;
  if (k -= Ebits) {
    d0 = Exp_1 | y << k | z >> 32 - k;
    y = xa > xa0 ? *--xa : 0;
    d1 = z << k | y >> 32 - k;
  } else {
    d0 = Exp_1 | y;
    d1 = z;
  }
#else
  if (k < Ebits + 16) {
    z = xa > xa0 ? *--xa : 0;
    d0 = Exp_1 | y << k - Ebits | z >> Ebits + 16 - k;
    w = xa > xa0 ? *--xa : 0;
    y = xa > xa0 ? *--xa : 0;
    d1 = z << k + 16 - Ebits | w << k - Ebits | y >> 16 + Ebits - k;
    goto ret_d;
  }
  z = xa > xa0 ? *--xa : 0;
  w = xa > xa0 ? *--xa : 0;
  k -= Ebits + 16;
  d0 = Exp_1 | y << k + 16 | z << k | w >> 16 - k;
  y = xa > xa0 ? *--xa : 0;
  d1 = w << k + 16 | y << k;
#endif
ret_d:
#ifdef VAX
  word0(d) = d0 >> 16 | d0 << 16;
  word1(d) = d1 >> 16 | d1 << 16;
#else
#  undef d0
#  undef d1
#endif
  return dval(d);
}

static Bigint* d2b
#ifdef KR_headers
    (dd, e, bits) double dd;
int *e, *bits;
#else
    (double dd, int* e, int* bits)
#endif
{
  U d;
  Bigint* b;
  int de, k;
  ULong *x, y, z;
#ifndef Sudden_Underflow
  int i;
#endif
#ifdef VAX
  ULong d0, d1;
#endif

  dval(d) = dd;
#ifdef VAX
  d0 = word0(d) >> 16 | word0(d) << 16;
  d1 = word1(d) >> 16 | word1(d) << 16;
#else
#  define d0 word0(d)
#  define d1 word1(d)
#endif

#ifdef Pack_32
  b = Balloc(1);
#else
  b = Balloc(2);
#endif
  x = b->x;

  z = d0 & Frac_mask;
  d0 &= 0x7fffffff; /* clear sign bit, which we ignore */
#ifdef Sudden_Underflow
  de = (int)(d0 >> Exp_shift);
#  ifndef IBM
  z |= Exp_msk11;
#  endif
#else
  if (de = (int)(d0 >> Exp_shift)) {
    z |= Exp_msk1;
  }
#endif
#ifdef Pack_32
  if (y = d1) {
    if (k = lo0bits(&y)) {
      x[0] = y | z << 32 - k;
      z >>= k;
    } else {
      x[0] = y;
    }
#  ifndef Sudden_Underflow
    i =
#  endif
        b->wds = (x[1] = z) ? 2 : 1;
  } else {
    k = lo0bits(&z);
    x[0] = z;
#  ifndef Sudden_Underflow
    i =
#  endif
        b->wds = 1;
    k += 32;
  }
#else
  if (y = d1) {
    if (k = lo0bits(&y))
      if (k >= 16) {
        x[0] = y | z << 32 - k & 0xffff;
        x[1] = z >> k - 16 & 0xffff;
        x[2] = z >> k;
        i = 2;
      } else {
        x[0] = y & 0xffff;
        x[1] = y >> 16 | z << 16 - k & 0xffff;
        x[2] = z >> k & 0xffff;
        x[3] = z >> k + 16;
        i = 3;
      }
    else {
      x[0] = y & 0xffff;
      x[1] = y >> 16;
      x[2] = z & 0xffff;
      x[3] = z >> 16;
      i = 3;
    }
  } else {
#  ifdef DEBUG
    if (!z) {
      Bug("Zero passed to d2b");
    }
#  endif
    k = lo0bits(&z);
    if (k >= 16) {
      x[0] = z;
      i = 0;
    } else {
      x[0] = z & 0xffff;
      x[1] = z >> 16;
      i = 1;
    }
    k += 32;
  }
  while (!x[i]) {
    --i;
  }
  b->wds = i + 1;
#endif
#ifndef Sudden_Underflow
  if (de) {
#endif
#ifdef IBM
    *e = (de - Bias - (P - 1) << 2) + k;
    *bits = 4 * P + 8 - k - hi0bits(word0(d) & Frac_mask);
#else
  *e = de - Bias - (P - 1) + k;
  *bits = P - k;
#endif
#ifndef Sudden_Underflow
  } else {
    *e = de - Bias - (P - 1) + 1 + k;
#  ifdef Pack_32
    *bits = 32 * i - hi0bits(x[i - 1]);
#  else
    *bits = (i + 2) * 16 - hi0bits(x[i]);
#  endif
  }
#endif
  return b;
}
#undef d0
#undef d1

static double ratio
#ifdef KR_headers
    (a, b) Bigint *a,
    *b;
#else
    (Bigint* a, Bigint* b)
#endif
{
  U da, db;
  int k, ka, kb;

  dval(da) = b2d(a, &ka);
  dval(db) = b2d(b, &kb);
#ifdef Pack_32
  k = ka - kb + 32 * (a->wds - b->wds);
#else
  k = ka - kb + 16 * (a->wds - b->wds);
#endif
#ifdef IBM
  if (k > 0) {
    word0(da) += (k >> 2) * Exp_msk1;
    if (k &= 3) {
      dval(da) *= 1 << k;
    }
  } else {
    k = -k;
    word0(db) += (k >> 2) * Exp_msk1;
    if (k &= 3) {
      dval(db) *= 1 << k;
    }
  }
#else
  if (k > 0) {
    word0(da) += k * Exp_msk1;
  } else {
    k = -k;
    word0(db) += k * Exp_msk1;
  }
#endif
  return dval(da) / dval(db);
}

static CONST double tens[] = {1e0,
                              1e1,
                              1e2,
                              1e3,
                              1e4,
                              1e5,
                              1e6,
                              1e7,
                              1e8,
                              1e9,
                              1e10,
                              1e11,
                              1e12,
                              1e13,
                              1e14,
                              1e15,
                              1e16,
                              1e17,
                              1e18,
                              1e19,
                              1e20,
                              1e21,
                              1e22
#ifdef VAX
                              ,
                              1e23,
                              1e24
#endif
};

static CONST double
#ifdef IEEE_Arith
    bigtens[] = {1e16, 1e32, 1e64, 1e128, 1e256};
static CONST double tinytens[] = {1e-16, 1e-32, 1e-64, 1e-128,
#  ifdef Avoid_Underflow
                                  9007199254740992. * 9007199254740992.e-256
/* = 2^106 * 1e-53 */
#  else
                                  1e-256
#  endif
};
/* The factor of 2^53 in tinytens[4] helps us avoid setting the underflow */
/* flag unnecessarily.  It leads to a song and dance at the end of strtod. */
#  define Scale_Bit 0x10
#  define n_bigtens 5
#else
#  ifdef IBM
    bigtens[] = {1e16, 1e32, 1e64};
static CONST double tinytens[] = {1e-16, 1e-32, 1e-64};
#    define n_bigtens 3
#  else
    bigtens[] = {1e16, 1e32};
static CONST double tinytens[] = {1e-16, 1e-32};
#    define n_bigtens 2
#  endif
#endif

#ifndef IEEE_Arith
#  undef INFNAN_CHECK
#endif

#ifdef INFNAN_CHECK

#  ifndef NAN_WORD0
#    define NAN_WORD0 0x7ff80000
#  endif

#  ifndef NAN_WORD1
#    define NAN_WORD1 0
#  endif

static int match
#  ifdef KR_headers
    (sp, t) char **sp,
    *t;
#  else
    (CONST char** sp, char* t)
#  endif
{
  int c, d;
  CONST char* s = *sp;

  while (d = *t++) {
    if ((c = *++s) >= 'A' && c <= 'Z') {
      c += 'a' - 'A';
    }
    if (c != d) {
      return 0;
    }
  }
  *sp = s + 1;
  return 1;
}

#  ifndef No_Hex_NaN
static void hexnan
#    ifdef KR_headers
    (rvp, sp) double* rvp;
CONST char** sp;
#    else
    (double* rvp, CONST char** sp)
#    endif
{
  ULong c, x[2];
  CONST char* s;
  int havedig, udx0, xshift;

  x[0] = x[1] = 0;
  havedig = xshift = 0;
  udx0 = 1;
  s = *sp;
  while (c = *(CONST unsigned char*)++s) {
    if (c >= '0' && c <= '9') {
      c -= '0';
    } else if (c >= 'a' && c <= 'f') {
      c += 10 - 'a';
    } else if (c >= 'A' && c <= 'F') {
      c += 10 - 'A';
    } else if (c <= ' ') {
      if (udx0 && havedig) {
        udx0 = 0;
        xshift = 1;
      }
      continue;
    } else if (/*(*/ c == ')' && havedig) {
      *sp = s + 1;
      break;
    } else {
      return; /* invalid form: don't change *sp */
    }
    havedig = 1;
    if (xshift) {
      xshift = 0;
      x[0] = x[1];
      x[1] = 0;
    }
    if (udx0) {
      x[0] = (x[0] << 4) | (x[1] >> 28);
    }
    x[1] = (x[1] << 4) | c;
  }
  if ((x[0] &= 0xfffff) || x[1]) {
    word0(*rvp) = Exp_mask | x[0];
    word1(*rvp) = x[1];
  }
}
#  endif /*No_Hex_NaN*/
#endif   /* INFNAN_CHECK */

PR_IMPLEMENT(double)
PR_strtod
#ifdef KR_headers
    (s00, se) CONST char* s00;
char** se;
#else
    (CONST char* s00, char** se)
#endif
{
#ifdef Avoid_Underflow
  int scale;
#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, aadj1, adj;
  U aadj2, rv, rv0;
  Long L;
  ULong y, z;
  Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
#ifdef SET_INEXACT
  int inexact, oldinexact;
#endif
#ifdef Honor_FLT_ROUNDS
  int rounding;
#endif
#ifdef USE_LOCALE
  CONST char* s2;
#endif

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }

  sign = nz0 = nz = 0;
  dval(rv) = 0.;
  for (s = s00;; s++) switch (*s) {
      case '-':
        sign = 1;
      /* no break */
      case '+':
        if (*++s) {
          goto break2;
        }
      /* no break */
      case 0:
        goto ret0;
      case '\t':
      case '\n':
      case '\v':
      case '\f':
      case '\r':
      case ' ':
        continue;
      default:
        goto break2;
    }
break2:
  if (*s == '0') {
    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
  s1 = localeconv()->decimal_point;
  if (c == *s1) {
    c = '.';
    if (*++s1) {
      s2 = s;
      for (;;) {
        if (*++s2 != *s1) {
          c = 0;
          break;
        }
        if (!*++s1) {
          s = s2;
          break;
        }
      }
    }
  }
#endif
  if (c == '.') {
    c = *++s;
    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:
  if (nd > 64 * 1024) {
    goto ret0;
  }
  e = 0;
  if (c == 'e' || c == 'E') {
    if (!nd && !nz && !nz0) {
      goto ret0;
    }
    s00 = s;
    esign = 0;
    switch (c = *++s) {
      case '-':
        esign = 1;
      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 */
      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")) {
            word0(rv) = NAN_WORD0;
            word1(rv) = NAN_WORD1;
#  ifndef No_Hex_NaN
            if (*s == '(') { /*)*/
              hexnan(&rv, &s);
            }
#  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;
    }
    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 = -rv;
          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 = -rv;
          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 = -rv;
        sign = 0;
      }
#  endif
      /* rv = */ rounded_quotient(dval(rv), tens[-e]);
      goto ret;
    }
#endif
  }
  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 = Flt_Rounds) >= 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) {
      dval(rv) *= tens[i];
    }
    if (e1 &= ~15) {
      if (e1 > DBL_MAX_10_EXP) {
      ovfl:
#ifndef NO_ERRNO
        PR_SetError(PR_RANGE_ERROR, 0);
#endif
        /* 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*/
        if (bd0) {
          goto retfree;
        }
        goto ret;
      }
      e1 >>= 4;
      for (j = 0; e1 > 1; j++, 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) {
      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 >>= 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) &= 0xffffffff << j - 32;
          }
        } else {
          word1(rv) &= 0xffffffff << j;
        }
      }
#else
      for (j = 0; e1 > 1; j++, 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.;
#ifndef NO_ERRNO
        PR_SetError(PR_RANGE_ERROR, 0);
#endif
        if (bd0) {
          goto retfree;
        }
        goto ret;
      }
#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);

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

  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
  j = bbe - scale;
  i = j + bbbits - 1; /* logb(rv) */
  if (i < Emin) {     /* denormal */
    j += P - Emin;
  } else {
    j = P + 1 - bbbits;
  }
#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);
    bb1 = mult(bs, bb);
    Bfree(bb);
    bb = bb1;
  }
  if (bb2 > 0) {
    bb = lshift(bb, bb2);
  }
  if (bd5 > 0) {
    bd = pow5mult(bd, bd5);
  }
  if (bd2 > 0) {
    bd = lshift(bd, bd2);
  }
  if (bs2 > 0) {
    bs = lshift(bs, bs2);
  }
  delta = diff(bb, bd);
  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) {
          adj = 1.;
          goto apply_adj;
        }
      } else if (!dsign) {
        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) {
              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(dval(rv));
          word0(rv) -= P * Exp_msk1;
        } else
#    endif /*Sudden_Underflow*/
#  endif   /*Avoid_Underflow*/
        dval(rv) += adj * ulp(dval(rv));
      }
      break;
    }
    adj = ratio(delta, bs);
    if (adj < 1.) {
      adj = 1.;
    }
    if (adj <= 0x7ffffffe) {
      /* adj = rounding ? ceil(adj) : floor(adj); */
      y = adj;
      if (y != adj) {
        if (!((rounding >> 1) ^ dsign)) {
          y++;
        }
        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;
      adj *= ulp(dval(rv));
      if (dsign) {
        dval(rv) += adj;
      } else {
        dval(rv) -= adj;
      }
      word0(rv) -= P * Exp_msk1;
      goto cont;
    }
#    endif /*Sudden_Underflow*/
#  endif   /*Avoid_Underflow*/
    adj *= ulp(dval(rv));
    if (dsign) {
      dval(rv) += adj;
    } else {
      dval(rv) -= adj;
    }
    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*/
        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
    if (!(word1(rv) & LSB)) {
      break;
    }
#endif
    if (dsign) {
      dval(rv) += ulp(dval(rv));
    }
#ifndef ROUND_BIASED
    else {
      dval(rv) -= ulp(dval(rv));
#  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 = aadj1 = 1.;
    } else if (word1(rv) || word0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
      if (word1(rv) == Tiny1 && !word0(rv)) {
        goto undfl;
      }
#endif
      aadj = 1.;
      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;
      }
      aadj1 = -aadj;
    }
  } else {
    aadj *= 0.5;
    aadj1 = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
    switch (Rounding) {
      case 2: /* towards +infinity */
        aadj1 -= 0.5;
        break;
      case 0: /* towards 0 */
      case 3: /* towards -infinity */
        aadj1 += 0.5;
    }
#else
        if (Flt_Rounds == 0) {
          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;
    adj = aadj1 * ulp(dval(rv));
    dval(rv) += 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;
        aadj1 = dsign ? aadj : -aadj;
      }
      dval(aadj2) = aadj1;
      word0(aadj2) += (2 * P + 1) * Exp_msk1 - y;
      aadj1 = dval(aadj2);
    }
    adj = aadj1 * ulp(dval(rv));
    dval(rv) += adj;
#else
#  ifdef Sudden_Underflow
        if ((word0(rv) & Exp_mask) <= P * Exp_msk1) {
          dval(rv0) = dval(rv);
          word0(rv) += P * Exp_msk1;
          adj = aadj1 * ulp(dval(rv));
          dval(rv) += 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 {
          adj = aadj1 * ulp(dval(rv));
          dval(rv) += adj;
        }
#  else  /*Sudden_Underflow*/
        /* Compute adj so that the IEEE rounding rules will
         * correctly round rv + 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.) {
          aadj1 = (double)(int)(aadj + 0.5);
          if (!dsign) {
            aadj1 = -aadj1;
          }
        }
        adj = aadj1 * ulp(dval(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);
}
#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 */
  if (word0(rv) == 0 && word1(rv) == 0) {
    PR_SetError(PR_RANGE_ERROR, 0);
  }
#  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
retfree: Bfree(bb);
Bfree(bd);
Bfree(bs);
Bfree(bd0);
Bfree(delta);
ret: if (se) { *se = (char*)s; }
return sign ? -dval(rv) : dval(rv);
}

static int quorem
#ifdef KR_headers
    (b, S)
Bigint *b, *S;
#else
      (Bigint * b, Bigint * S)
#endif
{
  int n;
  ULong *bx, *bxe, q, *sx, *sxe;
#ifdef ULLong
  ULLong borrow, carry, y, ys;
#else
    ULong borrow, carry, y, ys;
#  ifdef Pack_32
    ULong si, z, zs;
#  endif
#endif

  n = S->wds;
#ifdef DEBUG
  /*debug*/ if (b->wds > n)
  /*debug*/ {
    Bug("oversize b in quorem");
  }
#endif
  if (b->wds < n) {
    return 0;
  }
  sx = S->x;
  sxe = sx + --n;
  bx = b->x;
  bxe = bx + n;
  q = *bxe / (*sxe + 1); /* ensure q <= true quotient */
#ifdef DEBUG
  /*debug*/ if (q > 9)
  /*debug*/ {
    Bug("oversized quotient in quorem");
  }
#endif
  if (q) {
    borrow = 0;
    carry = 0;
    do {
#ifdef ULLong
      ys = *sx++ * (ULLong)q + carry;
      carry = ys >> 32;
      y = *bx - (ys & FFFFFFFF) - borrow;
      borrow = y >> 32 & (ULong)1;
      *bx++ = y & FFFFFFFF;
#else
#  ifdef Pack_32
        si = *sx++;
        ys = (si & 0xffff) * q + carry;
        zs = (si >> 16) * q + (ys >> 16);
        carry = zs >> 16;
        y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
        borrow = (y & 0x10000) >> 16;
        z = (*bx >> 16) - (zs & 0xffff) - borrow;
        borrow = (z & 0x10000) >> 16;
        Storeinc(bx, z, y);
#  else
        ys = *sx++ * q + carry;
        carry = ys >> 16;
        y = *bx - (ys & 0xffff) - borrow;
        borrow = (y & 0x10000) >> 16;
        *bx++ = y & 0xffff;
#  endif
#endif
    } while (sx <= sxe);
    if (!*bxe) {
      bx = b->x;
      while (--bxe > bx && !*bxe) {
        --n;
      }
      b->wds = n;
    }
  }
  if (cmp(b, S) >= 0) {
    q++;
    borrow = 0;
    carry = 0;
    bx = b->x;
    sx = S->x;
    do {
#ifdef ULLong
      ys = *sx++ + carry;
      carry = ys >> 32;
      y = *bx - (ys & FFFFFFFF) - borrow;
      borrow = y >> 32 & (ULong)1;
      *bx++ = y & FFFFFFFF;
#else
#  ifdef Pack_32
        si = *sx++;
        ys = (si & 0xffff) + carry;
        zs = (si >> 16) + (ys >> 16);
        carry = zs >> 16;
        y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
        borrow = (y & 0x10000) >> 16;
        z = (*bx >> 16) - (zs & 0xffff) - borrow;
        borrow = (z & 0x10000) >> 16;
        Storeinc(bx, z, y);
#  else
        ys = *sx++ + carry;
        carry = ys >> 16;
        y = *bx - (ys & 0xffff) - borrow;
        borrow = (y & 0x10000) >> 16;
        *bx++ = y & 0xffff;
#  endif
#endif
    } while (sx <= sxe);
    bx = b->x;
    bxe = bx + n;
    if (!*bxe) {
      while (--bxe > bx && !*bxe) {
        --n;
      }
      b->wds = n;
    }
  }
  return q;
}

#ifndef MULTIPLE_THREADS
static char* dtoa_result;
#endif

static char*
#ifdef KR_headers
rv_alloc(i)
int i;
#else
  rv_alloc(int i)
#endif
{
  int j, k, *r;

  j = sizeof(ULong);
  for (k = 0; sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= i; j <<= 1) {
    k++;
  }
  r = (int*)Balloc(k);
  *r = k;
  return
#ifndef MULTIPLE_THREADS
      dtoa_result =
#endif
          (char*)(r + 1);
}

static char*
#ifdef KR_headers
nrv_alloc(s, rve, n)
char *s, **rve;
int n;
#else
  nrv_alloc(char* s, char** rve, int n)
#endif
{
  char *rv, *t;

  t = rv = rv_alloc(n);
  while (*t = *s++) {
    t++;
  }
  if (rve) {
    *rve = t;
  }
  return rv;
}

/* freedtoa(s) must be used to free values s returned by dtoa
 * when MULTIPLE_THREADS is #defined.  It should be used in all cases,
 * but for consistency with earlier versions of dtoa, it is optional
 * when MULTIPLE_THREADS is not defined.
 */

static void
#ifdef KR_headers
    freedtoa(s) char* s;
#else
  freedtoa(char* s)
#endif
{
  Bigint* b = (Bigint*)((int*)s - 1);
  b->maxwds = 1 << (b->k = *(int*)b);
  Bfree(b);
#ifndef MULTIPLE_THREADS
  if (s == dtoa_result) {
    dtoa_result = 0;
  }
#endif
}

/* dtoa for IEEE arithmetic (dmg): convert double to ASCII string.
 *
 * Inspired by "How to Print Floating-Point Numbers Accurately" by
 * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 112-126].
 *
 * Modifications:
 *  1. Rather than iterating, we use a simple numeric overestimate
 *     to determine k = floor(log10(d)).  We scale relevant
 *     quantities using O(log2(k)) rather than O(k) multiplications.
 *  2. For some modes > 2 (corresponding to ecvt and fcvt), we don't
 *     try to generate digits strictly left to right.  Instead, we
 *     compute with fewer bits and propagate the carry if necessary
 *     when rounding the final digit up.  This is often faster.
 *  3. Under the assumption that input will be rounded nearest,
 *     mode 0 renders 1e23 as 1e23 rather than 9.999999999999999e22.
 *     That is, we allow equality in stopping tests when the
 *     round-nearest rule will give the same floating-point value
 *     as would satisfaction of the stopping test with strict
 *     inequality.
 *  4. We remove common factors of powers of 2 from relevant
 *     quantities.
 *  5. When converting floating-point integers less than 1e16,
 *     we use floating-point arithmetic rather than resorting
 *     to multiple-precision integers.
 *  6. When asked to produce fewer than 15 digits, we first try
 *     to get by with floating-point arithmetic; we resort to
 *     multiple-precision integer arithmetic only if we cannot
 *     guarantee that the floating-point calculation has given
 *     the correctly rounded result.  For k requested digits and
 *     "uniformly" distributed input, the probability is
 *     something like 10^(k-15) that we must resort to the Long
 *     calculation.
 */

static char* dtoa
#ifdef KR_headers
    (dd, mode, ndigits, decpt, sign, rve)
double dd;
int mode, ndigits, *decpt, *sign;
char** rve;
#else
      (double dd, int mode, int ndigits, int* decpt, int* sign, char** rve)
#endif
{
  /* Arguments ndigits, decpt, sign are similar to those
  of ecvt and fcvt; trailing zeros are suppressed from
  the returned string.  If not null, *rve is set to point
  to the end of the return value.  If d is +-Infinity or NaN,
  then *decpt is set to 9999.

  mode:
     0 ==> shortest string that yields d when read in
         and rounded to nearest.
     1 ==> like 0, but with Steele & White stopping rule;
         e.g. with IEEE P754 arithmetic , mode 0 gives
         1e23 whereas mode 1 gives 9.999999999999999e22.
     2 ==> max(1,ndigits) significant digits.  This gives a
         return value similar to that of ecvt, except
         that trailing zeros are suppressed.
     3 ==> through ndigits past the decimal point.  This
         gives a return value similar to that from fcvt,
         except that trailing zeros are suppressed, and
         ndigits can be negative.
     4,5 ==> similar to 2 and 3, respectively, but (in
         round-nearest mode) with the tests of mode 0 to
         possibly return a shorter string that rounds to d.
         With IEEE arithmetic and compilation with
         -DHonor_FLT_ROUNDS, modes 4 and 5 behave the same
         as modes 2 and 3 when FLT_ROUNDS != 1.
     6-9 ==> Debugging modes similar to mode - 4:  don't try
         fast floating-point estimate (if applicable).

     Values of mode other than 0-9 are treated as mode 0.

     Sufficient space is allocated to the return value
     to hold the suppressed trailing zeros.
  */

  int bbits, b2, b5, be, dig, i, ieps, ilim, ilim0, ilim1, j, j1, k, k0,
      k_check, leftright, m2, m5, s2, s5, spec_case, try_quick;
  Long L;
#ifndef Sudden_Underflow
  int denorm;
  ULong x;
#endif
  Bigint *b, *b1, *delta, *mlo, *mhi, *S;
  U d, d2, eps;
  double ds;
  char *s, *s0;
#ifdef Honor_FLT_ROUNDS
  int rounding;
#endif
#ifdef SET_INEXACT
  int inexact, oldinexact;
#endif

#ifndef MULTIPLE_THREADS
  if (dtoa_result) {
    freedtoa(dtoa_result);
    dtoa_result = 0;
  }
#endif

  dval(d) = dd;
  if (word0(d) & Sign_bit) {
    /* set sign for everything, including 0's and NaNs */
    *sign = 1;
    word0(d) &= ~Sign_bit; /* clear sign bit */
  } else {
    *sign = 0;
  }

#if defined(IEEE_Arith) + defined(VAX)
#  ifdef IEEE_Arith
  if ((word0(d) & Exp_mask) == Exp_mask)
#  else
  if (word0(d) == 0x8000)
#  endif
  {
    /* Infinity or NaN */
    *decpt = 9999;
#  ifdef IEEE_Arith
    if (!word1(d) && !(word0(d) & 0xfffff)) {
      return nrv_alloc("Infinity", rve, 8);
    }
#  endif
    return nrv_alloc("NaN", rve, 3);
  }
#endif
#ifdef IBM
  dval(d) += 0; /* normalize */
#endif
  if (!dval(d)) {
    *decpt = 1;
    return nrv_alloc("0", rve, 1);
  }

#ifdef SET_INEXACT
  try_quick = oldinexact = get_inexact();
  inexact = 1;
#endif
#ifdef Honor_FLT_ROUNDS
  if ((rounding = Flt_Rounds) >= 2) {
    if (*sign) {
      rounding = rounding == 2 ? 0 : 2;
    } else if (rounding != 2) {
      rounding = 0;
    }
  }
#endif

  b = d2b(dval(d), &be, &bbits);
#ifdef Sudden_Underflow
  i = (int)(word0(d) >> Exp_shift1 & (Exp_mask >> Exp_shift1));
#else
    if (i = (int)(word0(d) >> Exp_shift1 & (Exp_mask >> Exp_shift1))) {
#endif
  dval(d2) = dval(d);
  word0(d2) &= Frac_mask1;
  word0(d2) |= Exp_11;
#ifdef IBM
  if (j = 11 - hi0bits(word0(d2) & Frac_mask)) {
    dval(d2) /= 1 << j;
  }
#endif

  /* log(x)   ~=~ log(1.5) + (x-1.5)/1.5
   * log10(x)  =  log(x) / log(10)
   *      ~=~ log(1.5)/log(10) + (x-1.5)/(1.5*log(10))
   * log10(d) = (i-Bias)*log(2)/log(10) + log10(d2)
   *
   * This suggests computing an approximation k to log10(d) by
   *
   * k = (i - Bias)*0.301029995663981
   *  + ( (d2-1.5)*0.289529654602168 + 0.176091259055681 );
   *
   * We want k to be too large rather than too small.
   * The error in the first-order Taylor series approximation
   * is in our favor, so we just round up the constant enough
   * to compensate for any error in the multiplication of
   * (i - Bias) by 0.301029995663981; since |i - Bias| <= 1077,
   * and 1077 * 0.30103 * 2^-52 ~=~ 7.2e-14,
   * adding 1e-13 to the constant term more than suffices.
   * Hence we adjust the constant term to 0.1760912590558.
   * (We could get a more accurate k by invoking log10,
   *  but this is probably not worthwhile.)
   */

  i -= Bias;
#ifdef IBM
  i <<= 2;
  i += j;
#endif
#ifndef Sudden_Underflow
  denorm = 0;
}
else {
  /* d is denormalized */

  i = bbits + be + (Bias + (P - 1) - 1);
  x = i > 32 ? word0(d) << 64 - i | word1(d) >> i - 32 : word1(d) << 32 - i;
  dval(d2) = x;
  word0(d2) -= 31 * Exp_msk1; /* adjust exponent */
  i -= (Bias + (P - 1) - 1) + 1;
  denorm = 1;
}
#endif
ds = (dval(d2) - 1.5) * 0.289529654602168 + 0.1760912590558 +
     i * 0.301029995663981;
k = (int)ds;
if (ds < 0. && ds != k) {
  k--; /* want k = floor(ds) */
}
k_check = 1;
if (k >= 0 && k <= Ten_pmax) {
  if (dval(d) < tens[k]) {
    k--;
  }
  k_check = 0;
}
j = bbits - i - 1;
if (j >= 0) {
  b2 = 0;
  s2 = j;
} else {
  b2 = -j;
  s2 = 0;
}
if (k >= 0) {
  b5 = 0;
  s5 = k;
  s2 += k;
} else {
  b2 -= k;
  b5 = -k;
  s5 = 0;
}
if (mode < 0 || mode > 9) {
  mode = 0;
}

#ifndef SET_INEXACT
#  ifdef Check_FLT_ROUNDS
try_quick = Rounding == 1;
#  else
try_quick = 1;
#  endif
#endif /*SET_INEXACT*/

if (mode > 5) {
  mode -= 4;
  try_quick = 0;
}
leftright = 1;
switch (mode) {
  case 0:
  case 1:
    ilim = ilim1 = -1;
    i = 18;
    ndigits = 0;
    break;
  case 2:
    leftright = 0;
  /* no break */
  case 4:
    if (ndigits <= 0) {
      ndigits = 1;
    }
    ilim = ilim1 = i = ndigits;
    break;
  case 3:
    leftright = 0;
  /* no break */
  case 5:
    i = ndigits + k + 1;
    ilim = i;
    ilim1 = i - 1;
    if (i <= 0) {
      i = 1;
    }
}
s = s0 = rv_alloc(i);

#ifdef Honor_FLT_ROUNDS
if (mode > 1 && rounding != 1) {
  leftright = 0;
}
#endif

if (ilim >= 0 && ilim <= Quick_max && try_quick) {
  /* Try to get by with floating-point arithmetic. */

  i = 0;
  dval(d2) = dval(d);
  k0 = k;
  ilim0 = ilim;
  ieps = 2; /* conservative */
  if (k > 0) {
    ds = tens[k & 0xf];
    j = k >> 4;
    if (j & Bletch) {
      /* prevent overflows */
      j &= Bletch - 1;
      dval(d) /= bigtens[n_bigtens - 1];
      ieps++;
    }
    for (; j; j >>= 1, i++)
      if (j & 1) {
        ieps++;
        ds *= bigtens[i];
      }
    dval(d) /= ds;
  } else if (j1 = -k) {
    dval(d) *= tens[j1 & 0xf];
    for (j = j1 >> 4; j; j >>= 1, i++)
      if (j & 1) {
        ieps++;
        dval(d) *= bigtens[i];
      }
  }
  if (k_check && dval(d) < 1. && ilim > 0) {
    if (ilim1 <= 0) {
      goto fast_failed;
    }
    ilim = ilim1;
    k--;
    dval(d) *= 10.;
    ieps++;
  }
  dval(eps) = ieps * dval(d) + 7.;
  word0(eps) -= (P - 1) * Exp_msk1;
  if (ilim == 0) {
    S = mhi = 0;
    dval(d) -= 5.;
    if (dval(d) > dval(eps)) {
      goto one_digit;
    }
    if (dval(d) < -dval(eps)) {
      goto no_digits;
    }
    goto fast_failed;
  }
#ifndef No_leftright
  if (leftright) {
    /* Use Steele & White method of only
     * generating digits needed.
     */
    dval(eps) = 0.5 / tens[ilim - 1] - dval(eps);
    for (i = 0;;) {
      L = dval(d);
      dval(d) -= L;
      *s++ = '0' + (int)L;
      if (dval(d) < dval(eps)) {
        goto ret1;
      }
      if (1. - dval(d) < dval(eps)) {
        goto bump_up;
      }
      if (++i >= ilim) {
        break;
      }
      dval(eps) *= 10.;
      dval(d) *= 10.;
    }
  } else {
#endif
    /* Generate ilim digits, then fix them up. */
    dval(eps) *= tens[ilim - 1];
    for (i = 1;; i++, dval(d) *= 10.) {
      L = (Long)(dval(d));
      if (!(dval(d) -= L)) {
        ilim = i;
      }
      *s++ = '0' + (int)L;
      if (i == ilim) {
        if (dval(d) > 0.5 + dval(eps)) {
          goto bump_up;
        } else if (dval(d) < 0.5 - dval(eps)) {
          while (*--s == '0');
          s++;
          goto ret1;
        }
        break;
      }
    }
#ifndef No_leftright
  }
#endif
fast_failed:
  s = s0;
  dval(d) = dval(d2);
  k = k0;
  ilim = ilim0;
}

/* Do we have a "small" integer? */

if (be >= 0 && k <= Int_max) {
  /* Yes. */
  ds = tens[k];
  if (ndigits < 0 && ilim <= 0) {
    S = mhi = 0;
    if (ilim < 0 || dval(d) <= 5 * ds) {
      goto no_digits;
    }
    goto one_digit;
  }
  for (i = 1; i <= k + 1; i++, dval(d) *= 10.) {
    L = (Long)(dval(d) / ds);
    dval(d) -= L * ds;
#ifdef Check_FLT_ROUNDS
    /* If FLT_ROUNDS == 2, L will usually be high by 1 */
    if (dval(d) < 0) {
      L--;
      dval(d) += ds;
    }
#endif
    *s++ = '0' + (int)L;
    if (!dval(d)) {
#ifdef SET_INEXACT
      inexact = 0;
#endif
      break;
    }
    if (i == ilim) {
#ifdef Honor_FLT_ROUNDS
      if (mode > 1) switch (rounding) {
          case 0:
            goto ret1;
          case 2:
            goto bump_up;
        }
#endif
      dval(d) += dval(d);
      if (dval(d) > ds || dval(d) == ds && L & 1) {
      bump_up:
        while (*--s == '9')
          if (s == s0) {
            k++;
            *s = '0';
            break;
          }
        ++*s++;
      }
      break;
    }
  }
  goto ret1;
}

m2 = b2;
m5 = b5;
mhi = mlo = 0;
if (leftright) {
  i =
#ifndef Sudden_Underflow
      denorm ? be + (Bias + (P - 1) - 1 + 1) :
#endif
#ifdef IBM
             1 + 4 * P - 3 - bbits + ((bbits + be - 1) & 3);
#else
            1 + P - bbits;
#endif
  b2 += i;
  s2 += i;
  mhi = i2b(1);
}
if (m2 > 0 && s2 > 0) {
  i = m2 < s2 ? m2 : s2;
  b2 -= i;
  m2 -= i;
  s2 -= i;
}
if (b5 > 0) {
  if (leftright) {
    if (m5 > 0) {
      mhi = pow5mult(mhi, m5);
      b1 = mult(mhi, b);
      Bfree(b);
      b = b1;
    }
    if (j = b5 - m5) {
      b = pow5mult(b, j);
    }
  } else {
    b = pow5mult(b, b5);
  }
}
S = i2b(1);
if (s5 > 0) {
  S = pow5mult(S, s5);
}

/* Check for special case that d is a normalized power of 2. */

spec_case = 0;
if ((mode < 2 || leftright)
#ifdef Honor_FLT_ROUNDS
    && rounding == 1
#endif
) {
  if (!word1(d) && !(word0(d) & Bndry_mask)
#ifndef Sudden_Underflow
      && word0(d) & (Exp_mask & ~Exp_msk1)
#endif
  ) {
    /* The special case */
    b2 += Log2P;
    s2 += Log2P;
    spec_case = 1;
  }
}

/* Arrange for convenient computation of quotients:
 * shift left if necessary so divisor has 4 leading 0 bits.
 *
 * Perhaps we should just compute leading 28 bits of S once
 * and for all and pass them and a shift to quorem, so it
 * can do shifts and ors to compute the numerator for q.
 */
#ifdef Pack_32
if (i = ((s5 ? 32 - hi0bits(S->x[S->wds - 1]) : 1) + s2) & 0x1f) {
  i = 32 - i;
}
#else
      if (i = ((s5 ? 32 - hi0bits(S->x[S->wds - 1]) : 1) + s2) & 0xf) {
        i = 16 - i;
      }
#endif
if (i > 4) {
  i -= 4;
  b2 += i;
  m2 += i;
  s2 += i;
} else if (i < 4) {
  i += 28;
  b2 += i;
  m2 += i;
  s2 += i;
}
if (b2 > 0) {
  b = lshift(b, b2);
}
if (s2 > 0) {
  S = lshift(S, s2);
}
if (k_check) {
  if (cmp(b, S) < 0) {
    k--;
    b = multadd(b, 10, 0); /* we botched the k estimate */
    if (leftright) {
      mhi = multadd(mhi, 10, 0);
    }
    ilim = ilim1;
  }
}
if (ilim <= 0 && (mode == 3 || mode == 5)) {
  if (ilim < 0 || cmp(b, S = multadd(S, 5, 0)) <= 0) {
    /* no digits, fcvt style */
  no_digits:
    k = -1 - ndigits;
    goto ret;
  }
one_digit:
  *s++ = '1';
  k++;
  goto ret;
}
if (leftright) {
  if (m2 > 0) {
    mhi = lshift(mhi, m2);
  }

  /* Compute mlo -- check for special case
   * that d is a normalized power of 2.
   */

  mlo = mhi;
  if (spec_case) {
    mhi = Balloc(mhi->k);
    Bcopy(mhi, mlo);
    mhi = lshift(mhi, Log2P);
  }

  for (i = 1;; i++) {
    dig = quorem(b, S) + '0';
    /* Do we yet have the shortest decimal string
     * that will round to d?
     */
    j = cmp(b, mlo);
    delta = diff(S, mhi);
    j1 = delta->sign ? 1 : cmp(b, delta);
    Bfree(delta);
#ifndef ROUND_BIASED
    if (j1 == 0 && mode != 1 && !(word1(d) & 1)
#  ifdef Honor_FLT_ROUNDS
        && rounding >= 1
#  endif
    ) {
      if (dig == '9') {
        goto round_9_up;
      }
      if (j > 0) {
        dig++;
      }
#  ifdef SET_INEXACT
      else if (!b->x[0] && b->wds <= 1) {
        inexact = 0;
      }
#  endif
      *s++ = dig;
      goto ret;
    }
#endif
    if (j < 0 || j == 0 && mode != 1
#ifndef ROUND_BIASED
                     && !(word1(d) & 1)
#endif
    ) {
      if (!b->x[0] && b->wds <= 1) {
#ifdef SET_INEXACT
        inexact = 0;
#endif
        goto accept_dig;
      }
#ifdef Honor_FLT_ROUNDS
      if (mode > 1) switch (rounding) {
          case 0:
            goto accept_dig;
          case 2:
            goto keep_dig;
        }
#endif /*Honor_FLT_ROUNDS*/
      if (j1 > 0) {
        b = lshift(b, 1);
        j1 = cmp(b, S);
        if ((j1 > 0 || j1 == 0 && dig & 1) && dig++ == '9') {
          goto round_9_up;
        }
      }
    accept_dig:
      *s++ = dig;
      goto ret;
    }
    if (j1 > 0) {
#ifdef Honor_FLT_ROUNDS
      if (!rounding) {
        goto accept_dig;
      }
#endif
      if (dig == '9') { /* possible if i == 1 */
      round_9_up:
        *s++ = '9';
        goto roundoff;
      }
      *s++ = dig + 1;
      goto ret;
    }
#ifdef Honor_FLT_ROUNDS
  keep_dig:
#endif
    *s++ = dig;
    if (i == ilim) {
      break;
    }
    b = multadd(b, 10, 0);
    if (mlo == mhi) {
      mlo = mhi = multadd(mhi, 10, 0);
    } else {
      mlo = multadd(mlo, 10, 0);
      mhi = multadd(mhi, 10, 0);
    }
  }
} else
  for (i = 1;; i++) {
    *s++ = dig = quorem(b, S) + '0';
    if (!b->x[0] && b->wds <= 1) {
#ifdef SET_INEXACT
      inexact = 0;
#endif
      goto ret;
    }
    if (i >= ilim) {
      break;
    }
    b = multadd(b, 10, 0);
  }

  /* Round off last digit */

#ifdef Honor_FLT_ROUNDS
switch (rounding) {
  case 0:
    goto trimzeros;
  case 2:
    goto roundoff;
}
#endif
b = lshift(b, 1);
j = cmp(b, S);
if (j > 0 || j == 0 && dig & 1) {
roundoff:
  while (*--s == '9')
    if (s == s0) {
      k++;
      *s++ = '1';
      goto ret;
    }
  ++*s++;
} else {
#ifdef Honor_FLT_ROUNDS
trimzeros:
#endif
  while (*--s == '0');
  s++;
}
ret: Bfree(S);
if (mhi) {
  if (mlo && mlo != mhi) {
    Bfree(mlo);
  }
  Bfree(mhi);
}
ret1:
#ifdef SET_INEXACT
    if (inexact) {
  if (!oldinexact) {
    word0(d) = Exp_1 + (70 << Exp_shift);
    word1(d) = 0;
    dval(d) += 1.;
  }
}
else if (!oldinexact) {
  clear_inexact();
}
#endif
Bfree(b);
*s = 0;
*decpt = k + 1;
if (rve) {
  *rve = s;
}
return s0;
}
#ifdef __cplusplus
}
#endif

PR_IMPLEMENT(PRStatus)
PR_dtoa(PRFloat64 d, PRIntn mode, PRIntn ndigits, PRIntn* decpt, PRIntn* sign,
        char** rve, char* buf, PRSize bufsize) {
  char* result;
  PRSize resultlen;
  PRStatus rv = PR_FAILURE;

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }

  if (mode < 0 || mode > 3) {
    PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
    return rv;
  }
  result = dtoa(d, mode, ndigits, decpt, sign, rve);
  if (!result) {
    PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
    return rv;
  }
  resultlen = strlen(result) + 1;
  if (bufsize < resultlen) {
    PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);
  } else {
    memcpy(buf, result, resultlen);
    if (rve) {
      *rve = buf + (*rve - result);
    }
    rv = PR_SUCCESS;
  }
  freedtoa(result);
  return rv;
}

/*
** conversion routines for floating point
** prcsn - number of digits of precision to generate floating
** point value.
** This should be reparameterized so that you can send in a
**   prcn for the positive and negative ranges.  For now,
**   conform to the ECMA JavaScript spec which says numbers
**   less than 1e-6 are in scientific notation.
** Also, the ECMA spec says that there should always be a
**   '+' or '-' after the 'e' in scientific notation
*/
PR_IMPLEMENT(void)
PR_cnvtf(char* buf, int bufsz, int prcsn, double dfval) {
  PRIntn decpt, sign, numdigits;
  char *num, *nump;
  char* bufp = buf;
  char* endnum;
  U fval;

  dval(fval) = dfval;
  /* If anything fails, we store an empty string in 'buf' */
  num = (char*)PR_MALLOC(bufsz);
  if (num == NULL) {
    buf[0] = '\0';
    return;
  }
  /* XXX Why use mode 1? */
  if (PR_dtoa(dval(fval), 1, prcsn, &decpt, &sign, &endnum, num, bufsz) ==
      PR_FAILURE) {
    buf[0] = '\0';
    goto done;
  }
  numdigits = endnum - num;
  nump = num;

  if (sign && !(word0(fval) == Sign_bit && word1(fval) == 0) &&
      !((word0(fval) & Exp_mask) == Exp_mask &&
        (word1(fval) || (word0(fval) & 0xfffff)))) {
    *bufp++ = '-';
  }

  if (decpt == 9999) {
    while ((*bufp++ = *nump++) != 0) {
    } /* nothing to execute */
    goto done;
  }

  if (decpt > (prcsn + 1) || decpt < -(prcsn - 1) || decpt < -5) {
    *bufp++ = *nump++;
    if (numdigits != 1) {
      *bufp++ = '.';
    }

    while (*nump != '\0') {
      *bufp++ = *nump++;
    }
    *bufp++ = 'e';
    PR_snprintf(bufp, bufsz - (bufp - buf), "%+d", decpt - 1);
  } else if (decpt >= 0) {
    if (decpt == 0) {
      *bufp++ = '0';
    } else {
      while (decpt--) {
        if (*nump != '\0') {
          *bufp++ = *nump++;
        } else {
          *bufp++ = '0';
        }
      }
    }
    if (*nump != '\0') {
      *bufp++ = '.';
      while (*nump != '\0') {
        *bufp++ = *nump++;
      }
    }
    *bufp++ = '\0';
  } else if (decpt < 0) {
    *bufp++ = '0';
    *bufp++ = '.';
    while (decpt++) {
      *bufp++ = '0';
    }

    while (*nump != '\0') {
      *bufp++ = *nump++;
    }
    *bufp++ = '\0';
  }
done:
  PR_DELETE(num);
}