168 lines
3.8 KiB
C
168 lines
3.8 KiB
C
/****************************************************************
|
|
|
|
The author of this software is David M. Gay.
|
|
|
|
Copyright (C) 1998, 2000 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 "."). */
|
|
|
|
#include "gdtoaimp.h"
|
|
|
|
static double
|
|
#ifdef KR_headers
|
|
ulpdown(d) double *d;
|
|
#else
|
|
ulpdown(double *d)
|
|
#endif
|
|
{
|
|
double u;
|
|
ULong *L = (ULong*)d;
|
|
|
|
u = ulp(*d);
|
|
if (!(L[_1] | L[_0] & 0xfffff)
|
|
&& (L[_0] & 0x7ff00000) > 0x00100000)
|
|
u *= 0.5;
|
|
return u;
|
|
}
|
|
|
|
int
|
|
#ifdef KR_headers
|
|
strtodI(s, sp, dd) CONST char *s; char **sp; double *dd;
|
|
#else
|
|
strtodI(CONST char *s, char **sp, double *dd)
|
|
#endif
|
|
{
|
|
static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI };
|
|
ULong bits[2], sign;
|
|
Long exp;
|
|
int j, k;
|
|
typedef union {
|
|
double d[2];
|
|
ULong L[4];
|
|
} U;
|
|
U *u;
|
|
|
|
k = strtodg(s, sp, &fpi, &exp, bits);
|
|
u = (U*)dd;
|
|
sign = k & STRTOG_Neg ? 0x80000000L : 0;
|
|
switch(k & STRTOG_Retmask) {
|
|
case STRTOG_NoNumber:
|
|
u->d[0] = u->d[1] = 0.;
|
|
break;
|
|
|
|
case STRTOG_Zero:
|
|
u->d[0] = u->d[1] = 0.;
|
|
#ifdef Sudden_Underflow
|
|
if (k & STRTOG_Inexact) {
|
|
if (sign)
|
|
u->L[_0] = 0x80100000L;
|
|
else
|
|
u->L[2+_0] = 0x100000L;
|
|
}
|
|
break;
|
|
#else
|
|
goto contain;
|
|
#endif
|
|
|
|
case STRTOG_Denormal:
|
|
u->L[_1] = bits[0];
|
|
u->L[_0] = bits[1];
|
|
goto contain;
|
|
|
|
case STRTOG_Normal:
|
|
u->L[_1] = bits[0];
|
|
u->L[_0] = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20);
|
|
contain:
|
|
j = k & STRTOG_Inexact;
|
|
if (sign) {
|
|
u->L[_0] |= sign;
|
|
j = STRTOG_Inexact - j;
|
|
}
|
|
switch(j) {
|
|
case STRTOG_Inexlo:
|
|
#ifdef Sudden_Underflow
|
|
if ((u->L[_0] & 0x7ff00000) < 0x3500000) {
|
|
u->L[2+_0] = u->L[_0] + 0x3500000;
|
|
u->L[2+_1] = u->L[_1];
|
|
u->d[1] += ulp(u->d[1]);
|
|
u->L[2+_0] -= 0x3500000;
|
|
if (!(u->L[2+_0] & 0x7ff00000)) {
|
|
u->L[2+_0] = sign;
|
|
u->L[2+_1] = 0;
|
|
}
|
|
}
|
|
else
|
|
#endif
|
|
u->d[1] = u->d[0] + ulp(u->d[0]);
|
|
break;
|
|
case STRTOG_Inexhi:
|
|
u->d[1] = u->d[0];
|
|
#ifdef Sudden_Underflow
|
|
if ((u->L[_0] & 0x7ff00000) < 0x3500000) {
|
|
u->L[_0] += 0x3500000;
|
|
u->d[0] -= ulpdown(u->d);
|
|
u->L[_0] -= 0x3500000;
|
|
if (!(u->L[_0] & 0x7ff00000)) {
|
|
u->L[_0] = sign;
|
|
u->L[_1] = 0;
|
|
}
|
|
}
|
|
else
|
|
#endif
|
|
u->d[0] -= ulpdown(u->d);
|
|
break;
|
|
default:
|
|
u->d[1] = u->d[0];
|
|
}
|
|
break;
|
|
|
|
case STRTOG_Infinite:
|
|
u->L[_0] = u->L[2+_0] = sign | 0x7ff00000;
|
|
u->L[_1] = u->L[2+_1] = 0;
|
|
if (k & STRTOG_Inexact) {
|
|
if (sign) {
|
|
u->L[2+_0] = 0xffefffffL;
|
|
u->L[2+_1] = 0xffffffffL;
|
|
}
|
|
else {
|
|
u->L[_0] = 0x7fefffffL;
|
|
u->L[_1] = 0xffffffffL;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case STRTOG_NaN:
|
|
u->L[0] = u->L[2] = d_QNAN0;
|
|
u->L[1] = u->L[3] = d_QNAN1;
|
|
break;
|
|
|
|
case STRTOG_NaNbits:
|
|
u->L[_0] = u->L[2+_0] = 0x7ff00000 | sign | bits[1];
|
|
u->L[_1] = u->L[2+_1] = bits[0];
|
|
}
|
|
return k;
|
|
}
|