diff options
Diffstat (limited to 'gdtoa/strtodI.c')
| -rw-r--r-- | gdtoa/strtodI.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/gdtoa/strtodI.c b/gdtoa/strtodI.c new file mode 100644 index 0000000..98f8891 --- /dev/null +++ b/gdtoa/strtodI.c @@ -0,0 +1,167 @@ +/**************************************************************** + +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; + } |
