Linux 4.1.18
[linux/fpc-iii.git] / arch / mips / math-emu / dp_div.c
blobf4746f7c5f63b1f686d51b5a59fd6d5dcd85d0be
1 /* IEEE754 floating point arithmetic
2 * double precision: common utilities
3 */
4 /*
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
15 * for more details.
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)
26 u64 rm;
27 int re;
28 u64 bm;
30 COMPXDP;
31 COMPYDP;
33 EXPLODEXDP;
34 EXPLODEYDP;
36 ieee754_clearcx();
38 FLUSHXDP;
39 FLUSHYDP;
41 switch (CLPAIR(xc, yc)) {
42 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
43 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
44 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
45 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
46 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
47 return ieee754dp_nanxcpt(y);
49 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
50 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
51 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
52 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
53 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
54 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
55 return ieee754dp_nanxcpt(x);
57 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
58 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
59 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
60 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
61 return y;
63 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
64 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
65 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
66 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
67 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
68 return x;
72 * Infinity handling
74 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
75 ieee754_setcx(IEEE754_INVALID_OPERATION);
76 return ieee754dp_indef();
78 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
79 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
80 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
81 return ieee754dp_zero(xs ^ ys);
83 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
84 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
85 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
86 return ieee754dp_inf(xs ^ ys);
89 * Zero handling
91 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
92 ieee754_setcx(IEEE754_INVALID_OPERATION);
93 return ieee754dp_indef();
95 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
96 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
97 ieee754_setcx(IEEE754_ZERO_DIVIDE);
98 return ieee754dp_inf(xs ^ ys);
100 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
101 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
102 return ieee754dp_zero(xs == ys ? 0 : 1);
104 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
105 DPDNORMX;
107 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
108 DPDNORMY;
109 break;
111 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
112 DPDNORMX;
113 break;
115 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
116 break;
118 assert(xm & DP_HIDDEN_BIT);
119 assert(ym & DP_HIDDEN_BIT);
121 /* provide rounding space */
122 xm <<= 3;
123 ym <<= 3;
125 /* now the dirty work */
127 rm = 0;
128 re = xe - ye;
130 for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) {
131 if (xm >= ym) {
132 xm -= ym;
133 rm |= bm;
134 if (xm == 0)
135 break;
137 xm <<= 1;
140 rm <<= 1;
141 if (xm)
142 rm |= 1; /* have remainder, set sticky */
144 assert(rm);
147 * Normalise rm to rounding precision ?
149 while ((rm >> (DP_FBITS + 3)) == 0) {
150 rm <<= 1;
151 re--;
154 return ieee754dp_format(xs == ys ? 0 : 1, re, rm);