138 lines
3.5 KiB
C
138 lines
3.5 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 "gdtoaimp.h"
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int
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#ifdef KR_headers
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strtoIg(s00, se, fpi, exp, B, rvp) CONST char *s00; char **se; FPI *fpi; Long *exp; Bigint **B; int *rvp;
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#else
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strtoIg(CONST char *s00, char **se, FPI *fpi, Long *exp, Bigint **B, int *rvp)
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#endif
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{
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Bigint *b, *b1;
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int i, nb, nw, nw1, rv, rv1, swap;
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unsigned int nb1, nb11;
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Long e1;
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b = *B;
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rv = strtodg(s00, se, fpi, exp, b->x);
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if (!(rv & STRTOG_Inexact)) {
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B[1] = 0;
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return *rvp = rv;
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}
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e1 = exp[0];
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rv1 = rv ^ STRTOG_Inexact;
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b1 = Balloc(b->k);
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Bcopy(b1, b);
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nb = fpi->nbits;
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nb1 = nb & 31;
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nb11 = (nb1 - 1) & 31;
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nw = b->wds;
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nw1 = nw - 1;
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if (rv & STRTOG_Inexlo) {
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swap = 0;
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b1 = increment(b1);
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if ((rv & STRTOG_Retmask) == STRTOG_Zero) {
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if (fpi->sudden_underflow) {
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b1->x[0] = 0;
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b1->x[nw1] = 1L << nb11;
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rv1 += STRTOG_Normal - STRTOG_Zero;
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rv1 &= ~STRTOG_Underflow;
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goto swapcheck;
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}
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rv1 &= STRTOG_Inexlo | STRTOG_Underflow | STRTOG_Zero;
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rv1 |= STRTOG_Inexhi | STRTOG_Denormal;
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goto swapcheck;
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}
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if (b1->wds > nw
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|| (nb1 && b1->x[nw1] & 1L << nb1)) {
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if (++e1 > fpi->emax)
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rv1 = STRTOG_Infinite | STRTOG_Inexhi;
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rshift(b1, 1);
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}
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else if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
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if (b1->x[nw1] & 1L << nb11) {
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rv1 += STRTOG_Normal - STRTOG_Denormal;
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rv1 &= ~STRTOG_Underflow;
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}
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}
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}
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else {
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swap = STRTOG_Neg;
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if ((rv & STRTOG_Retmask) == STRTOG_Infinite) {
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b1 = set_ones(b1, nb);
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e1 = fpi->emax;
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rv1 = STRTOG_Normal | STRTOG_Inexlo;
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goto swapcheck;
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}
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decrement(b1);
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if ((rv & STRTOG_Retmask) == STRTOG_Denormal) {
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for(i = nw1; !b1->x[i]; --i)
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if (!i) {
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rv1 = STRTOG_Zero | STRTOG_Inexlo;
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break;
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}
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goto swapcheck;
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}
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if (!(b1->x[nw1] & 1L << nb11)) {
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if (e1 == fpi->emin) {
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if (fpi->sudden_underflow)
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rv1 += STRTOG_Zero - STRTOG_Normal;
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else
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rv1 += STRTOG_Denormal - STRTOG_Normal;
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rv1 |= STRTOG_Underflow;
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}
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else {
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b1 = lshift(b1, 1);
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b1->x[0] |= 1;
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--e1;
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}
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}
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}
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swapcheck:
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if (swap ^ (rv & STRTOG_Neg)) {
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rvp[0] = rv1;
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rvp[1] = rv;
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B[0] = b1;
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B[1] = b;
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exp[1] = exp[0];
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exp[0] = e1;
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}
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else {
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rvp[0] = rv;
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rvp[1] = rv1;
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B[1] = b1;
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exp[1] = e1;
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}
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return rv;
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}
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