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cc36ccd13b
strings and floating point.
185 lines
4.4 KiB
C
185 lines
4.4 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
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David M. Gay
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Bell Laboratories, Room 2C-463
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600 Mountain Avenue
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Murray Hill, NJ 07974-0636
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U.S.A.
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dmg@bell-labs.com
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*/
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#include "gdtoaimp.h"
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int
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#ifdef KR_headers
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strtopdd(s, sp, dd) CONST char *s; char **sp; double *dd;
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#else
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strtopdd(CONST char *s, char **sp, double *dd)
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#endif
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{
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#ifdef Sudden_Underflow
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static FPI fpi = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
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#else
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static FPI fpi = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
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#endif
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ULong bits[4];
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Long exp;
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int i, j, rv;
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typedef union {
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double d[2];
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ULong L[4];
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} U;
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U *u;
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rv = strtodg(s, sp, &fpi, &exp, bits);
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u = (U*)dd;
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switch(rv & STRTOG_Retmask) {
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case STRTOG_NoNumber:
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case STRTOG_Zero:
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u->d[0] = u->d[1] = 0.;
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break;
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case STRTOG_Normal:
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u->L[_1] = (bits[1] >> 21 | bits[2] << 11) & 0xffffffffL;
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u->L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
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| exp + 0x3ff + 105 << 20;
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exp += 0x3ff + 52;
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if (bits[1] &= 0x1fffff) {
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i = hi0bits(bits[1]) - 11;
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if (i >= exp) {
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i = exp - 1;
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exp = 0;
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}
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else
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exp -= i;
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if (i > 0) {
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bits[1] = bits[1] << i | bits[0] >> 32-i;
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bits[0] = bits[0] << i & 0xffffffffL;
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}
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}
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else if (bits[0]) {
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i = hi0bits(bits[0]) + 21;
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if (i >= exp) {
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i = exp - 1;
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exp = 0;
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}
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else
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exp -= i;
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if (i < 32) {
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bits[1] = bits[0] >> 32 - i;
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bits[0] = bits[0] << i & 0xffffffffL;
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}
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else {
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bits[1] = bits[0] << i - 32;
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bits[0] = 0;
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}
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}
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else {
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u->L[2] = u->L[3] = 0;
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break;
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}
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u->L[2+_1] = bits[0];
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u->L[2+_0] = bits[1] & 0xfffff | exp << 20;
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break;
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case STRTOG_Denormal:
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if (bits[3])
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goto nearly_normal;
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if (bits[2])
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goto partly_normal;
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if (bits[1] & 0xffe00000)
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goto hardly_normal;
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/* completely denormal */
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u->L[2] = u->L[3] = 0;
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u->L[_1] = bits[0];
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u->L[_0] = bits[1];
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break;
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nearly_normal:
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i = hi0bits(bits[3]) - 11; /* i >= 12 */
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j = 32 - i;
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u->L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
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| 65 - i << 20;
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u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
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u->L[2+_0] = bits[1] & (1L << j) - 1;
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u->L[2+_1] = bits[0];
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break;
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partly_normal:
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i = hi0bits(bits[2]) - 11;
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if (i < 0) {
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j = -i;
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i += 32;
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u->L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
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u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
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u->L[2+_0] = bits[1] & (1L << j) - 1;
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u->L[2+_1] = bits[0];
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break;
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}
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if (i == 0) {
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u->L[_0] = bits[2] & 0xfffff | 33 << 20;
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u->L[_1] = bits[1];
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u->L[2+_0] = 0;
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u->L[2+_1] = bits[0];
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break;
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}
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j = 32 - i;
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u->L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
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| j + 1 << 20;
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u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
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u->L[2+_0] = 0;
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u->L[2+_1] = bits[0] & (1L << j) - 1;
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break;
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hardly_normal:
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j = 11 - hi0bits(bits[1]);
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i = 32 - j;
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u->L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
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u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
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u->L[2+_0] = 0;
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u->L[2+_1] = bits[0] & (1L << j) - 1;
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break;
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case STRTOG_Infinite:
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u->L[_0] = u->L[2+_0] = 0x7ff00000;
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u->L[_1] = u->L[2+_1] = 0;
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break;
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case STRTOG_NaN:
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u->L[_0] = u->L[2+_0] = 0x7fffffff;
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u->L[_1] = u->L[2+_1] = (ULong)-1;
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}
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if (rv & STRTOG_Neg) {
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u->L[ _0] |= 0x80000000L;
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u->L[2+_0] |= 0x80000000L;
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}
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return rv;
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}
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