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kolibrios/contrib/sdk/sources/newlib/libc/stdlib/strtod.c

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upload sdk git-svn-id: svn://kolibrios.org@4349 a494cfbc-eb01-0410-851d-a64ba20cac60
2013-12-15 09:09:20 +01:00
/*
FUNCTION
<<strtod>>, <<strtof>>---string to double or float
INDEX
strtod
INDEX
_strtod_r
INDEX
strtof
ANSI_SYNOPSIS
#include <stdlib.h>
double strtod(const char *<[str]>, char **<[tail]>);
float strtof(const char *<[str]>, char **<[tail]>);
double _strtod_r(void *<[reent]>,
const char *<[str]>, char **<[tail]>);
TRAD_SYNOPSIS
#include <stdlib.h>
double strtod(<[str]>,<[tail]>)
char *<[str]>;
char **<[tail]>;
float strtof(<[str]>,<[tail]>)
char *<[str]>;
char **<[tail]>;
double _strtod_r(<[reent]>,<[str]>,<[tail]>)
char *<[reent]>;
char *<[str]>;
char **<[tail]>;
DESCRIPTION
The function <<strtod>> parses the character string <[str]>,
producing a substring which can be converted to a double
value. The substring converted is the longest initial
subsequence of <[str]>, beginning with the first
non-whitespace character, that has one of these formats:
.[+|-]<[digits]>[.[<[digits]>]][(e|E)[+|-]<[digits]>]
.[+|-].<[digits]>[(e|E)[+|-]<[digits]>]
.[+|-](i|I)(n|N)(f|F)[(i|I)(n|N)(i|I)(t|T)(y|Y)]
.[+|-](n|N)(a|A)(n|N)[<(>[<[hexdigits]>]<)>]
.[+|-]0(x|X)<[hexdigits]>[.[<[hexdigits]>]][(p|P)[+|-]<[digits]>]
.[+|-]0(x|X).<[hexdigits]>[(p|P)[+|-]<[digits]>]
The substring contains no characters if <[str]> is empty, consists
entirely of whitespace, or if the first non-whitespace
character is something other than <<+>>, <<->>, <<.>>, or a
digit, and cannot be parsed as infinity or NaN. If the platform
does not support NaN, then NaN is treated as an empty substring.
If the substring is empty, no conversion is done, and
the value of <[str]> is stored in <<*<[tail]>>>. Otherwise,
the substring is converted, and a pointer to the final string
(which will contain at least the terminating null character of
<[str]>) is stored in <<*<[tail]>>>. If you want no
assignment to <<*<[tail]>>>, pass a null pointer as <[tail]>.
<<strtof>> is identical to <<strtod>> except for its return type.
This implementation returns the nearest machine number to the
input decimal string. Ties are broken by using the IEEE
round-even rule. However, <<strtof>> is currently subject to
double rounding errors.
The alternate function <<_strtod_r>> is a reentrant version.
The extra argument <[reent]> is a pointer to a reentrancy structure.
RETURNS
<<strtod>> returns the converted substring value, if any. If
no conversion could be performed, 0 is returned. If the
correct value is out of the range of representable values,
plus or minus <<HUGE_VAL>> is returned, and <<ERANGE>> is
stored in errno. If the correct value would cause underflow, 0
is returned and <<ERANGE>> is stored in errno.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
*/
/****************************************************************
The author of this software is David M. Gay.
Copyright (C) 1998-2001 by Lucent Technologies
All Rights Reserved
Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of Lucent or any of its entities
not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.
LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.
****************************************************************/
/* Please send bug reports to David M. Gay (dmg at acm dot org,
* with " at " changed at "@" and " dot " changed to "."). */
/* Original file gdtoa-strtod.c Modified 06-21-2006 by Jeff Johnston to work within newlib. */
#include <_ansi.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "mprec.h"
#include "gdtoa.h"
#include "gd_qnan.h"
/* #ifndef NO_FENV_H */
/* #include <fenv.h> */
/* #endif */
#include "locale.h"
#ifdef IEEE_Arith
#ifndef NO_IEEE_Scale
#define Avoid_Underflow
#undef tinytens
/* 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. */
static _CONST double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128,
9007199254740992.e-256
};
#endif
#endif
#ifdef Honor_FLT_ROUNDS
#define Rounding rounding
#undef Check_FLT_ROUNDS
#define Check_FLT_ROUNDS
#else
#define Rounding Flt_Rounds
#endif
#ifndef NO_HEX_FP
static void
_DEFUN (ULtod, (L, bits, exp, k),
__ULong *L _AND
__ULong *bits _AND
Long exp _AND
int k)
{
switch(k & STRTOG_Retmask) {
case STRTOG_NoNumber:
case STRTOG_Zero:
L[0] = L[1] = 0;
break;
case STRTOG_Denormal:
L[_1] = bits[0];
L[_0] = bits[1];
break;
case STRTOG_Normal:
case STRTOG_NaNbits:
L[_1] = bits[0];
L[_0] = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20);
break;
case STRTOG_Infinite:
L[_0] = 0x7ff00000;
L[_1] = 0;
break;
case STRTOG_NaN:
L[_0] = 0x7fffffff;
L[_1] = (__ULong)-1;
}
if (k & STRTOG_Neg)
L[_0] |= 0x80000000L;
}
#endif /* !NO_HEX_FP */
#ifdef INFNAN_CHECK
static int
_DEFUN (match, (sp, t),
_CONST char **sp _AND
char *t)
{
int c, d;
_CONST char *s = *sp;
while( (d = *t++) !=0) {
if ((c = *++s) >= 'A' && c <= 'Z')
c += 'a' - 'A';
if (c != d)
return 0;
}
*sp = s + 1;
return 1;
}
#endif /* INFNAN_CHECK */
double
_DEFUN (_strtod_r, (ptr, s00, se),
struct _reent *ptr _AND
_CONST char *s00 _AND
char **se)
{
#ifdef Avoid_Underflow
int scale;
#endif
int bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, decpt, dsign,
e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
_CONST char *s, *s0, *s1;
double aadj, adj;
U aadj1, 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
delta = bs = bd = NULL;
sign = nz0 = nz = decpt = 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') {
#ifndef NO_HEX_FP
{
static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI };
Long exp;
__ULong bits[2];
switch(s[1]) {
case 'x':
case 'X':
/* If the number is not hex, then the parse of
0 is still valid. */
s00 = s + 1;
{
#if defined(FE_DOWNWARD) && defined(FE_TONEAREST) && defined(FE_TOWARDZERO) && defined(FE_UPWARD)
FPI fpi1 = fpi;
switch(fegetround()) {
case FE_TOWARDZERO: fpi1.rounding = 0; break;
case FE_UPWARD: fpi1.rounding = 2; break;
case FE_DOWNWARD: fpi1.rounding = 3;
}
#else
#define fpi1 fpi
#endif
switch((i = gethex(ptr, &s, &fpi1, &exp, &bb, sign)) & STRTOG_Retmask) {
case STRTOG_NoNumber:
s = s00;
case STRTOG_Zero:
break;
default:
if (bb) {
copybits(bits, fpi.nbits, bb);
Bfree(ptr,bb);
}
ULtod(rv.i, bits, exp, i);
}}
goto ret;
}
}
#endif
nz0 = 1;
while(*++s == '0') ;
if (!*s)
goto ret;
}
s0 = s;
y = z = 0;
for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++) {
if (nd < DBL_DIG + 1) {
if (nd < 9)
y = 10*y + c - '0';
else
z = 10*z + c - '0';
}
}
nd0 = nd;
if (strncmp (s, _localeconv_r (ptr)->decimal_point,
strlen (_localeconv_r (ptr)->decimal_point)) == 0) {
decpt = 1;
c = *(s += strlen (_localeconv_r (ptr)->decimal_point));
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') {
for(i = 1; i < nz; i++) {
if (nd <= DBL_DIG + 1) {
if (nd + i < 10)
y *= 10;
else
z *= 10;
}
}
if (nd <= DBL_DIG + 1) {
if (nd + i < 10)
y = 10*y + c;
else
z = 10*z + c;
}
if (nd <= DBL_DIG + 1) {
nf += nz;
nd += nz;
}
nz = 0;
}
}
}
dig_done:
e = 0;
if (c == 'e' || c == 'E') {
if (!nd && !nz && !nz0) {
goto ret0;
}
s00 = s;
esign = 0;
switch(c = *++s) {
case '-':
esign = 1;
case '+':
c = *++s;
}
if (c >= '0' && c <= '9') {
while(c == '0')
c = *++s;
if (c > '0' && c <= '9') {
L = c - '0';
s1 = s;
while((c = *++s) >= '0' && c <= '9')
L = 10*L + c - '0';
if (s - s1 > 8 || L > 19999)
/* Avoid confusion from exponents
* so large that e might overflow.
*/
e = 19999; /* safe for 16 bit ints */
else
e = (int)L;
if (esign)
e = -e;
}
else
e = 0;
}
else
s = s00;
}
if (!nd) {
if (!nz && !nz0) {
#ifdef INFNAN_CHECK
/* Check for Nan and Infinity */
__ULong bits[2];
static FPI fpinan = /* only 52 explicit bits */
{ 52, 1-1023-53+1, 2046-1023-53+1, 1, SI };
if (!decpt)
switch(c) {
case 'i':
case 'I':
if (match(&s,"nf")) {
--s;
if (!match(&s,"inity"))
++s;
dword0(rv) = 0x7ff00000;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
goto ret;
}
break;
case 'n':
case 'N':
if (match(&s, "an")) {
#ifndef No_Hex_NaN
if (*s == '(' /*)*/
&& hexnan(&s, &fpinan, bits)
== STRTOG_NaNbits) {
dword0(rv) = 0x7ff00000 | bits[1];
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = bits[0];
#endif /*!_DOUBLE_IS_32BITS*/
}
else {
#endif
dword0(rv) = NAN_WORD0;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = NAN_WORD1;
#endif /*!_DOUBLE_IS_32BITS*/
#ifndef No_Hex_NaN
}
#endif
goto ret;
}
}
#endif /* INFNAN_CHECK */
ret0:
s = s00;
sign = 0;
}
goto ret;
}
e1 = e -= nf;
/* Now we have nd0 digits, starting at s0, followed by a
* decimal point, followed by nd-nd0 digits. The number we're
* after is the integer represented by those digits times
* 10**e */
if (!nd0)
nd0 = nd;
k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;
dval(rv) = y;
if (k > 9) {
#ifdef SET_INEXACT
if (k > DBL_DIG)
oldinexact = get_inexact();
#endif
dval(rv) = tens[k - 9] * dval(rv) + z;
}
bd0 = 0;
if (nd <= DBL_DIG
#ifndef RND_PRODQUOT
#ifndef Honor_FLT_ROUNDS
&& Flt_Rounds == 1
#endif
#endif
) {
if (!e)
goto ret;
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) {
dval(rv) = -dval(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) {
dval(rv) = -dval(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:
dword0(rv) -= P*Exp_msk1;
/* rv = */ rounded_product(dval(rv), tens[e]);
if ((dword0(rv) & Exp_mask)
> Exp_msk1*(DBL_MAX_EXP+Bias-1-P))
goto ovfl;
dword0(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) {
dval(rv) = -dval(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) !=0)
dval(rv) *= tens[i];
if (e1 &= ~15) {
if (e1 > DBL_MAX_10_EXP) {
ovfl:
#ifndef NO_ERRNO
ptr->_errno = ERANGE;
#endif
/* Can't trust HUGE_VAL */
#ifdef IEEE_Arith
#ifdef Honor_FLT_ROUNDS
switch(rounding) {
case 0: /* toward 0 */
case 3: /* toward -infinity */
dword0(rv) = Big0;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = Big1;
#endif /*!_DOUBLE_IS_32BITS*/
break;
default:
dword0(rv) = Exp_mask;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
}
#else /*Honor_FLT_ROUNDS*/
dword0(rv) = Exp_mask;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
#endif /*Honor_FLT_ROUNDS*/
#ifdef SET_INEXACT
/* set overflow bit */
dval(rv0) = 1e300;
dval(rv0) *= dval(rv0);
#endif
#else /*IEEE_Arith*/
dword0(rv) = Big0;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = Big1;
#endif /*!_DOUBLE_IS_32BITS*/
#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. */
dword0(rv) -= P*Exp_msk1;
dval(rv) *= bigtens[j];
if ((z = dword0(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) */
dword0(rv) = Big0;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = Big1;
#endif /*!_DOUBLE_IS_32BITS*/
}
else
dword0(rv) += P*Exp_msk1;
}
}
else if (e1 < 0) {
e1 = -e1;
if ( (i = e1 & 15) !=0)
dval(rv) /= tens[i];
if (e1 >>= 4) {
if (e1 >= 1 << n_bigtens)
goto undfl;
#ifdef Avoid_Underflow
if (e1 & Scale_Bit)
scale = 2*P;
for(j = 0; e1 > 0; j++, e1 >>= 1)
if (e1 & 1)
dval(rv) *= tinytens[j];
if (scale && (j = 2*P + 1 - ((dword0(rv) & Exp_mask)
>> Exp_shift)) > 0) {
/* scaled rv is denormal; zap j low bits */
if (j >= 32) {
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
if (j >= 53)
dword0(rv) = (P+2)*Exp_msk1;
else
dword0(rv) &= 0xffffffff << (j-32);
}
#ifndef _DOUBLE_IS_32BITS
else
dword1(rv) &= 0xffffffff << j;
#endif /*!_DOUBLE_IS_32BITS*/
}
#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
ptr->_errno = ERANGE;
#endif
if (bd0)
goto retfree;
goto ret;
}
#ifndef Avoid_Underflow
#ifndef _DOUBLE_IS_32BITS
dword0(rv) = Tiny0;
dword1(rv) = Tiny1;
#else
dword0(rv) = Tiny1;
#endif /*_DOUBLE_IS_32BITS*/
/* 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(ptr, s0, nd0, nd, y);
for(;;) {
bd = Balloc(ptr,bd0->_k);
Bcopy(bd, bd0);
bb = d2b(ptr,dval(rv), &bbe, &bbbits); /* rv = bb * 2^bbe */
bs = i2b(ptr,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(ptr, bs, bb5);
bb1 = mult(ptr, bs, bb);
Bfree(ptr, bb);
bb = bb1;
}
if (bb2 > 0)
bb = lshift(ptr, bb, bb2);
if (bd5 > 0)
bd = pow5mult(ptr, bd, bd5);
if (bd2 > 0)
bd = lshift(ptr, bd, bd2);
if (bs2 > 0)
bs = lshift(ptr, bs, bs2);
delta = diff(ptr, 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 (!dword1(rv)
&& !(dword0(rv) & Frac_mask)) {
y = dword0(rv) & Exp_mask;
#ifdef Avoid_Underflow
if (!scale || y > 2*P*Exp_msk1)
#else
if (y)
#endif
{
delta = lshift(ptr, delta,Log2P);
if (cmp(delta, bs) <= 0)
adj = -0.5;
}
}
apply_adj:
#ifdef Avoid_Underflow
if (scale && (y = dword0(rv) & Exp_mask)
<= 2*P*Exp_msk1)
dword0(adj) += (2*P+1)*Exp_msk1 - y;
#else
#ifdef Sudden_Underflow
if ((dword0(rv) & Exp_mask) <=
P*Exp_msk1) {
dword0(rv) += P*Exp_msk1;
dval(rv) += adj*ulp(dval(rv));
dword0(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 = dword0(rv) & Exp_mask) <= 2*P*Exp_msk1)
dword0(adj) += (2*P+1)*Exp_msk1 - y;
#else
#ifdef Sudden_Underflow
if ((dword0(rv) & Exp_mask) <= P*Exp_msk1) {
dword0(rv) += P*Exp_msk1;
adj *= ulp(dval(rv));
if (dsign)
dval(rv) += adj;
else
dval(rv) -= adj;
dword0(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 || dword1(rv) || dword0(rv) & Bndry_mask
#ifdef IEEE_Arith
#ifdef Avoid_Underflow
|| (dword0(rv) & Exp_mask) <= (2*P+1)*Exp_msk1
#else
|| (dword0(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(ptr,delta,Log2P);
if (cmp(delta, bs) > 0)
goto drop_down;
break;
}
if (i == 0) {
/* exactly half-way between */
if (dsign) {
if ((dword0(rv) & Bndry_mask1) == Bndry_mask1
&& dword1(rv) == (
#ifdef Avoid_Underflow
(scale && (y = dword0(rv) & Exp_mask) <= 2*P*Exp_msk1)
? (0xffffffff & (0xffffffff << (2*P+1-(y>>Exp_shift)))) :
#endif
0xffffffff)) {
/*boundary case -- increment exponent*/
dword0(rv) = (dword0(rv) & Exp_mask)
+ Exp_msk1
#ifdef IBM
| Exp_msk1 >> 4
#endif
;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
#ifdef Avoid_Underflow
dsign = 0;
#endif
break;
}
}
else if (!(dword0(rv) & Bndry_mask) && !dword1(rv)) {
drop_down:
/* boundary case -- decrement exponent */
#ifdef Sudden_Underflow /*{{*/
L = dword0(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 = dword0(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 = (dword0(rv) & Exp_mask) - Exp_msk1;
#endif /*Sudden_Underflow}*/
dword0(rv) = L | Bndry_mask1;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = 0xffffffff;
#endif /*!_DOUBLE_IS_32BITS*/
#ifdef IBM
goto cont;
#else
break;
#endif
}
#ifndef ROUND_BIASED
if (!(dword1(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 = dval(aadj1) = 1.;
else if (dword1(rv) || dword0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
if (dword1(rv) == Tiny1 && !dword0(rv))
goto undfl;
#endif
aadj = 1.;
dval(aadj1) = -1.;
}
else {
/* special case -- power of FLT_RADIX to be */
/* rounded down... */
if (aadj < 2./FLT_RADIX)
aadj = 1./FLT_RADIX;
else
aadj *= 0.5;
dval(aadj1) = -aadj;
}
}
else {
aadj *= 0.5;
dval(aadj1) = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
switch(Rounding) {
case 2: /* towards +infinity */
dval(aadj1) -= 0.5;
break;
case 0: /* towards 0 */
case 3: /* towards -infinity */
dval(aadj1) += 0.5;
}
#else
if (Flt_Rounds == 0)
dval(aadj1) += 0.5;
#endif /*Check_FLT_ROUNDS*/
}
y = dword0(rv) & Exp_mask;
/* Check for overflow */
if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
dval(rv0) = dval(rv);
dword0(rv) -= P*Exp_msk1;
adj = dval(aadj1) * ulp(dval(rv));
dval(rv) += adj;
if ((dword0(rv) & Exp_mask) >=
Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
if (dword0(rv0) == Big0 && dword1(rv0) == Big1)
goto ovfl;
dword0(rv) = Big0;
#ifndef _DOUBLE_IS_32BITS
dword1(rv) = Big1;
#endif /*!_DOUBLE_IS_32BITS*/
goto cont;
}
else
dword0(rv) += P*Exp_msk1;
}
else {
#ifdef Avoid_Underflow
if (scale && y <= 2*P*Exp_msk1) {
if (aadj <= 0x7fffffff) {
if ((z = aadj) <= 0)
z = 1;
aadj = z;
dval(aadj1) = dsign ? aadj : -aadj;
}
dword0(aadj1) += (2*P+1)*Exp_msk1 - y;
}
adj = dval(aadj1) * ulp(dval(rv));
dval(rv) += adj;
#else
#ifdef Sudden_Underflow
if ((dword0(rv) & Exp_mask) <= P*Exp_msk1) {
dval(rv0) = dval(rv);
dword0(rv) += P*Exp_msk1;
adj = dval(aadj1) * ulp(dval(rv));
dval(rv) += adj;
#ifdef IBM
if ((dword0(rv) & Exp_mask) < P*Exp_msk1)
#else
if ((dword0(rv) & Exp_mask) <= P*Exp_msk1)
#endif
{
if (dword0(rv0) == Tiny0
&& dword1(rv0) == Tiny1)
goto undfl;
#ifndef _DOUBLE_IS_32BITS
dword0(rv) = Tiny0;
dword1(rv) = Tiny1;
#else
dword0(rv) = Tiny1;
#endif /*_DOUBLE_IS_32BITS*/
goto cont;
}
else
dword0(rv) -= P*Exp_msk1;
}
else {
adj = dval(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.) {
dval(aadj1) = (double)(int)(aadj + 0.5);
if (!dsign)
dval(aadj1) = -dval(aadj1);
}
adj = dval(aadj1) * ulp(dval(rv));
dval(rv) += adj;
#endif /*Sudden_Underflow*/
#endif /*Avoid_Underflow*/
}
z = dword0(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 || dword1(rv) || dword0(rv) & Bndry_mask) {
if (aadj < .4999999 || aadj > .5000001)
break;
}
else if (aadj < .4999999/FLT_RADIX)
break;
}
#endif
cont:
Bfree(ptr,bb);
Bfree(ptr,bd);
Bfree(ptr,bs);
Bfree(ptr,delta);
}
#ifdef SET_INEXACT
if (inexact) {
if (!oldinexact) {
dword0(rv0) = Exp_1 + (70 << Exp_shift);
#ifndef _DOUBLE_IS_32BITS
dword1(rv0) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
dval(rv0) += 1.;
}
}
else if (!oldinexact)
clear_inexact();
#endif
#ifdef Avoid_Underflow
if (scale) {
dword0(rv0) = Exp_1 - 2*P*Exp_msk1;
#ifndef _DOUBLE_IS_32BITS
dword1(rv0) = 0;
#endif /*!_DOUBLE_IS_32BITS*/
dval(rv) *= dval(rv0);
#ifndef NO_ERRNO
/* try to avoid the bug of testing an 8087 register value */
if (dword0(rv) == 0 && dword1(rv) == 0)
ptr->_errno = ERANGE;
#endif
}
#endif /* Avoid_Underflow */
#ifdef SET_INEXACT
if (inexact && !(dword0(rv) & Exp_mask)) {
/* set underflow bit */
dval(rv0) = 1e-300;
dval(rv0) *= dval(rv0);
}
#endif
retfree:
Bfree(ptr,bb);
Bfree(ptr,bd);
Bfree(ptr,bs);
Bfree(ptr,bd0);
Bfree(ptr,delta);
ret:
if (se)
*se = (char *)s;
return sign ? -dval(rv) : dval(rv);
}
#ifndef _REENT_ONLY
double
_DEFUN (strtod, (s00, se),
_CONST char *s00 _AND char **se)
{
return _strtod_r (_REENT, s00, se);
}
float
_DEFUN (strtof, (s00, se),
_CONST char *s00 _AND
char **se)
{
double retval = _strtod_r (_REENT, s00, se);
if (isnan (retval))
return nanf (NULL);
return (float)retval;
}
#endif
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