164 lines
3.9 KiB
C
164 lines
3.9 KiB
C
/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 1998, 2000 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 "gdtoaimp.h"
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static double
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#ifdef KR_headers
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ulpdown(d) U *d;
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#else
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ulpdown(U *d)
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#endif
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{
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double u;
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ULong *L = d->L;
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u = ulp(d);
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if (!(L[_1] | (L[_0] & 0xfffff))
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&& (L[_0] & 0x7ff00000) > 0x00100000)
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u *= 0.5;
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return u;
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}
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int
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#ifdef KR_headers
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strtodI(s, sp, dd) CONST char *s; char **sp; double *dd;
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#else
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strtodI(CONST char *s, char **sp, double *dd)
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#endif
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{
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static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI };
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ULong bits[2], sign;
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Long exp;
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int j, k;
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U *u;
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k = strtodg(s, sp, &fpi, &exp, bits);
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u = (U*)dd;
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sign = k & STRTOG_Neg ? 0x80000000L : 0;
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switch(k & STRTOG_Retmask) {
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case STRTOG_NoNumber:
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dval(&u[0]) = dval(&u[1]) = 0.;
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break;
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case STRTOG_Zero:
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dval(&u[0]) = dval(&u[1]) = 0.;
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#ifdef Sudden_Underflow
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if (k & STRTOG_Inexact) {
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if (sign)
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word0(&u[0]) = 0x80100000L;
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else
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word0(&u[1]) = 0x100000L;
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}
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break;
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#else
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goto contain;
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#endif
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case STRTOG_Denormal:
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word1(&u[0]) = bits[0];
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word0(&u[0]) = bits[1];
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goto contain;
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case STRTOG_Normal:
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word1(&u[0]) = bits[0];
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word0(&u[0]) = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20);
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contain:
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j = k & STRTOG_Inexact;
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if (sign) {
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word0(&u[0]) |= sign;
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j = STRTOG_Inexact - j;
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}
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switch(j) {
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case STRTOG_Inexlo:
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#ifdef Sudden_Underflow
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if ((u->L[_0] & 0x7ff00000) < 0x3500000) {
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word0(&u[1]) = word0(&u[0]) + 0x3500000;
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word1(&u[1]) = word1(&u[0]);
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dval(&u[1]) += ulp(&u[1]);
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word0(&u[1]) -= 0x3500000;
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if (!(word0(&u[1]) & 0x7ff00000)) {
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word0(&u[1]) = sign;
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word1(&u[1]) = 0;
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}
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}
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else
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#endif
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dval(&u[1]) = dval(&u[0]) + ulp(&u[0]);
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break;
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case STRTOG_Inexhi:
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dval(&u[1]) = dval(&u[0]);
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#ifdef Sudden_Underflow
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if ((word0(&u[0]) & 0x7ff00000) < 0x3500000) {
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word0(&u[0]) += 0x3500000;
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dval(&u[0]) -= ulpdown(u);
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word0(&u[0]) -= 0x3500000;
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if (!(word0(&u[0]) & 0x7ff00000)) {
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word0(&u[0]) = sign;
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word1(&u[0]) = 0;
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}
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}
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else
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#endif
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dval(&u[0]) -= ulpdown(u);
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break;
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default:
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dval(&u[1]) = dval(&u[0]);
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}
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break;
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case STRTOG_Infinite:
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word0(&u[0]) = word0(&u[1]) = sign | 0x7ff00000;
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word1(&u[0]) = word1(&u[1]) = 0;
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if (k & STRTOG_Inexact) {
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if (sign) {
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word0(&u[1]) = 0xffefffffL;
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word1(&u[1]) = 0xffffffffL;
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}
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else {
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word0(&u[0]) = 0x7fefffffL;
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word1(&u[0]) = 0xffffffffL;
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}
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}
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break;
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case STRTOG_NaN:
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u->L[0] = (u+1)->L[0] = d_QNAN0;
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u->L[1] = (u+1)->L[1] = d_QNAN1;
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break;
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case STRTOG_NaNbits:
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word0(&u[0]) = word0(&u[1]) = 0x7ff00000 | sign | bits[1];
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word1(&u[0]) = word1(&u[1]) = bits[0];
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}
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return k;
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}
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