355 lines
7.3 KiB
C
355 lines
7.3 KiB
C
/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 1998 by Lucent Technologies
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of Lucent or any of its entities
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not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior
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permission.
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LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
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SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
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IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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****************************************************************/
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/* Please send bug reports to David M. Gay (dmg at acm dot org,
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* with " at " changed at "@" and " dot " changed to "."). */
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#include <_ansi.h>
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#include <reent.h>
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#include <string.h>
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#include "mprec.h"
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#include "gdtoa.h"
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#include "gd_qnan.h"
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#include "locale.h"
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unsigned char hexdig[256];
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static void
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_DEFUN (htinit, (h, s, inc),
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unsigned char *h _AND
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unsigned char *s _AND
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int inc)
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{
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int i, j;
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for(i = 0; (j = s[i]) !=0; i++)
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h[j] = i + inc;
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}
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void
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_DEFUN_VOID (hexdig_init)
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{
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#define USC (unsigned char *)
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htinit(hexdig, USC "0123456789", 0x10);
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htinit(hexdig, USC "abcdef", 0x10 + 10);
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htinit(hexdig, USC "ABCDEF", 0x10 + 10);
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}
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static void
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_DEFUN(rshift, (b, k),
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_Bigint *b _AND
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int k)
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{
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__ULong *x, *x1, *xe, y;
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int n;
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x = x1 = b->_x;
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n = k >> kshift;
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if (n < b->_wds) {
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xe = x + b->_wds;
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x += n;
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if (k &= kmask) {
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n = ULbits - k;
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y = *x++ >> k;
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while(x < xe) {
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*x1++ = (y | (*x << n)) & ALL_ON;
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y = *x++ >> k;
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}
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if ((*x1 = y) !=0)
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x1++;
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}
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else
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while(x < xe)
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*x1++ = *x++;
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}
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if ((b->_wds = x1 - b->_x) == 0)
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b->_x[0] = 0;
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}
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static _Bigint *
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_DEFUN (increment, (ptr, b),
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struct _reent *ptr _AND
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_Bigint *b)
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{
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__ULong *x, *xe;
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_Bigint *b1;
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#ifdef Pack_16
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__ULong carry = 1, y;
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#endif
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x = b->_x;
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xe = x + b->_wds;
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#ifdef Pack_32
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do {
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if (*x < (__ULong)0xffffffffL) {
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++*x;
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return b;
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}
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*x++ = 0;
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} while(x < xe);
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#else
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do {
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y = *x + carry;
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carry = y >> 16;
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*x++ = y & 0xffff;
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if (!carry)
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return b;
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} while(x < xe);
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if (carry)
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#endif
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{
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if (b->_wds >= b->_maxwds) {
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b1 = Balloc(ptr, b->_k+1);
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Bcopy(b1, b);
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Bfree(ptr, b);
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b = b1;
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}
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b->_x[b->_wds++] = 1;
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}
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return b;
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}
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int
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_DEFUN(gethex, (ptr, sp, fpi, exp, bp, sign),
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struct _reent *ptr _AND
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_CONST char **sp _AND
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FPI *fpi _AND
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Long *exp _AND
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_Bigint **bp _AND
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int sign)
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{
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_Bigint *b;
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_CONST unsigned char *decpt, *s0, *s, *s1;
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int esign, havedig, irv, k, n, nbits, up, zret;
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__ULong L, lostbits, *x;
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Long e, e1;
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unsigned char *decimalpoint = (unsigned char *)
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_localeconv_r (ptr)->decimal_point;
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size_t decp_len = strlen ((const char *) decimalpoint);
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unsigned char decp_end = decimalpoint[decp_len - 1];
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if (!hexdig['0'])
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hexdig_init();
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havedig = 0;
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s0 = *(_CONST unsigned char **)sp + 2;
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while(s0[havedig] == '0')
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havedig++;
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s0 += havedig;
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s = s0;
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decpt = 0;
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zret = 0;
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e = 0;
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if (!hexdig[*s]) {
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zret = 1;
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if (strncmp ((const char *) s, (const char *) decimalpoint,
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decp_len) != 0)
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goto pcheck;
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decpt = (s += decp_len);
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if (!hexdig[*s])
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goto pcheck;
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while(*s == '0')
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s++;
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if (hexdig[*s])
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zret = 0;
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havedig = 1;
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s0 = s;
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}
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while(hexdig[*s])
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s++;
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if (strncmp ((const char *) s, (const char *) decimalpoint,
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decp_len) == 0
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&& !decpt) {
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decpt = (s += decp_len);
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while(hexdig[*s])
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s++;
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}
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if (decpt)
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e = -(((Long)(s-decpt)) << 2);
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pcheck:
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s1 = s;
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switch(*s) {
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case 'p':
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case 'P':
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esign = 0;
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switch(*++s) {
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case '-':
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esign = 1;
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/* no break */
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case '+':
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s++;
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}
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if ((n = hexdig[*s]) == 0 || n > 0x19) {
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s = s1;
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break;
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}
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e1 = n - 0x10;
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while((n = hexdig[*++s]) !=0 && n <= 0x19)
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e1 = 10*e1 + n - 0x10;
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if (esign)
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e1 = -e1;
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e += e1;
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}
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*sp = (char*)s;
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if (zret)
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return havedig ? STRTOG_Zero : STRTOG_NoNumber;
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n = s1 - s0 - 1;
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for(k = 0; n > 7; n >>= 1)
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k++;
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b = Balloc(ptr, k);
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x = b->_x;
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n = 0;
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L = 0;
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while(s1 > s0) {
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if (*--s1 == decp_end && s1 - decp_len + 1 >= s0
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&& strncmp ((const char *) s1 - decp_len + 1,
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(const char *) decimalpoint, decp_len) == 0) {
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s1 -= decp_len - 1; /* Note the --s1 above! */
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continue;
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}
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if (n == 32) {
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*x++ = L;
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L = 0;
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n = 0;
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}
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L |= (hexdig[*s1] & 0x0f) << n;
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n += 4;
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}
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*x++ = L;
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b->_wds = n = x - b->_x;
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n = 32*n - hi0bits(L);
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nbits = fpi->nbits;
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lostbits = 0;
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x = b->_x;
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if (n > nbits) {
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n -= nbits;
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if (any_on(b,n)) {
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lostbits = 1;
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k = n - 1;
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if (x[k>>kshift] & 1 << (k & kmask)) {
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lostbits = 2;
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if (k > 1 && any_on(b,k-1))
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lostbits = 3;
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}
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}
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rshift(b, n);
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e += n;
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}
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else if (n < nbits) {
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n = nbits - n;
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b = lshift(ptr, b, n);
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e -= n;
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x = b->_x;
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}
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if (e > fpi->emax) {
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ovfl:
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Bfree(ptr, b);
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*bp = 0;
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return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi;
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}
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irv = STRTOG_Normal;
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if (e < fpi->emin) {
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irv = STRTOG_Denormal;
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n = fpi->emin - e;
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if (n >= nbits) {
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switch (fpi->rounding) {
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case FPI_Round_near:
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if (n == nbits && (n < 2 || any_on(b,n-1)))
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goto one_bit;
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break;
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case FPI_Round_up:
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if (!sign)
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goto one_bit;
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break;
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case FPI_Round_down:
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if (sign) {
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one_bit:
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*exp = fpi->emin;
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x[0] = b->_wds = 1;
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*bp = b;
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return STRTOG_Denormal | STRTOG_Inexhi
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| STRTOG_Underflow;
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}
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}
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Bfree(ptr, b);
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*bp = 0;
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return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow;
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}
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k = n - 1;
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if (lostbits)
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lostbits = 1;
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else if (k > 0)
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lostbits = any_on(b,k);
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if (x[k>>kshift] & 1 << (k & kmask))
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lostbits |= 2;
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nbits -= n;
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rshift(b,n);
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e = fpi->emin;
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}
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if (lostbits) {
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up = 0;
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switch(fpi->rounding) {
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case FPI_Round_zero:
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break;
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case FPI_Round_near:
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if ((lostbits & 2)
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&& ((lostbits & 1) | (x[0] & 1)))
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up = 1;
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break;
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case FPI_Round_up:
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up = 1 - sign;
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break;
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case FPI_Round_down:
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up = sign;
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}
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if (up) {
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k = b->_wds;
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b = increment(ptr, b);
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x = b->_x;
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if (irv == STRTOG_Denormal) {
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if (nbits == fpi->nbits - 1
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&& x[nbits >> kshift] & 1 << (nbits & kmask))
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irv = STRTOG_Normal;
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}
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else if ((b->_wds > k)
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|| ((n = nbits & kmask) !=0
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&& (hi0bits(x[k-1]) < 32-n))) {
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rshift(b,1);
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if (++e > fpi->emax)
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goto ovfl;
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}
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irv |= STRTOG_Inexhi;
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}
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else
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irv |= STRTOG_Inexlo;
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}
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*bp = b;
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*exp = e;
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return irv;
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}
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