tor-browser

prdtoa.c (80688B)

---

/* -*- 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);
}