1 /* IEEE754 floating point arithmetic
2 * double precision: common utilities
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 * This program is free software; you can distribute it and/or modify it
9 * under the terms of the GNU General Public License (Version 2) as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
22 #include "ieee754dp.h"
24 union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y)
41 switch (CLPAIR(xc, yc)) {
42 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
43 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
44 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
45 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
46 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
47 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
48 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
49 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
50 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
51 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
52 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
53 ieee754_setcx(IEEE754_INVALID_OPERATION);
54 return ieee754dp_nanxcpt(ieee754dp_indef());
56 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
57 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
58 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
59 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
62 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
63 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
64 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
65 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
66 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
73 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
74 ieee754_setcx(IEEE754_INVALID_OPERATION);
75 return ieee754dp_indef();
77 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
78 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
79 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
80 return ieee754dp_zero(xs ^ ys);
82 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
83 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
84 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
85 return ieee754dp_inf(xs ^ ys);
90 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
91 ieee754_setcx(IEEE754_INVALID_OPERATION);
92 return ieee754dp_indef();
94 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
95 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
96 ieee754_setcx(IEEE754_ZERO_DIVIDE);
97 return ieee754dp_inf(xs ^ ys);
99 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
100 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
101 return ieee754dp_zero(xs == ys ? 0 : 1);
103 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
106 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
110 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
114 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
117 assert(xm & DP_HIDDEN_BIT);
118 assert(ym & DP_HIDDEN_BIT);
120 /* provide rounding space */
124 /* now the dirty work */
129 for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) {
141 rm |= 1; /* have remainder, set sticky */
146 * Normalise rm to rounding precision ?
148 while ((rm >> (DP_FBITS + 3)) == 0) {
153 return ieee754dp_format(xs == ys ? 0 : 1, re, rm);