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1/* IEEE754 floating point arithmetic
2 * single precision
3 */
4/*
5 * MIPS floating point support
6 * Copyright (C) 1994-2000 Algorithmics Ltd.
7 *
8 * ########################################################################
9 *
10 * This program is free software; you can distribute it and/or modify it
11 * under the terms of the GNU General Public License (Version 2) as
12 * published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 * for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
22 *
23 * ########################################################################
24 */
25
26
27#include "ieee754sp.h"
28
29ieee754sp ieee754sp_add(ieee754sp x, ieee754sp y)
30{
31 COMPXSP;
32 COMPYSP;
33
34 EXPLODEXSP;
35 EXPLODEYSP;
36
37 CLEARCX;
38
39 FLUSHXSP;
40 FLUSHYSP;
41
42 switch (CLPAIR(xc, yc)) {
43 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
44 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
45 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
46 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
47 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
48 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
49 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
50 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
51 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
52 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
53 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
54 SETCX(IEEE754_INVALID_OPERATION);
55 return ieee754sp_nanxcpt(ieee754sp_indef(), "add", x, y);
56
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;
62
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;
69
70
71 /* Infinity handling
72 */
73
74 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
75 if (xs == ys)
76 return x;
77 SETCX(IEEE754_INVALID_OPERATION);
78 return ieee754sp_xcpt(ieee754sp_indef(), "add", x, y);
79
80 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
81 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
82 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
83 return y;
84
85 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
86 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
87 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
88 return x;
89
90 /* Zero handling
91 */
92
93 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
94 if (xs == ys)
95 return x;
96 else
97 return ieee754sp_zero(ieee754_csr.rm ==
98 IEEE754_RD);
99
100 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
101 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
102 return x;
103
104 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
105 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
106 return y;
107
108 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
109 SPDNORMX;
110
111 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
112 SPDNORMY;
113 break;
114
115 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
116 SPDNORMX;
117 break;
118
119 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
120 break;
121 }
122 assert(xm & SP_HIDDEN_BIT);
123 assert(ym & SP_HIDDEN_BIT);
124
125 /* provide guard,round and stick bit space */
126 xm <<= 3;
127 ym <<= 3;
128
129 if (xe > ye) {
130 /* have to shift y fraction right to align
131 */
132 int s = xe - ye;
133 SPXSRSYn(s);
134 } else if (ye > xe) {
135 /* have to shift x fraction right to align
136 */
137 int s = ye - xe;
138 SPXSRSXn(s);
139 }
140 assert(xe == ye);
141 assert(xe <= SP_EMAX);
142
143 if (xs == ys) {
144 /* generate 28 bit result of adding two 27 bit numbers
145 * leaving result in xm,xs,xe
146 */
147 xm = xm + ym;
148 xe = xe;
149 xs = xs;
150
151 if (xm >> (SP_MBITS + 1 + 3)) { /* carry out */
152 SPXSRSX1();
153 }
154 } else {
155 if (xm >= ym) {
156 xm = xm - ym;
157 xe = xe;
158 xs = xs;
159 } else {
160 xm = ym - xm;
161 xe = xe;
162 xs = ys;
163 }
164 if (xm == 0)
165 return ieee754sp_zero(ieee754_csr.rm ==
166 IEEE754_RD);
167
168 /* normalize in extended single precision */
169 while ((xm >> (SP_MBITS + 3)) == 0) {
170 xm <<= 1;
171 xe--;
172 }
173
174 }
175 SPNORMRET2(xs, xe, xm, "add", x, y);
176}
1// SPDX-License-Identifier: GPL-2.0-only
2/* IEEE754 floating point arithmetic
3 * single precision
4 */
5/*
6 * MIPS floating point support
7 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 */
9
10#include "ieee754sp.h"
11
12union ieee754sp ieee754sp_add(union ieee754sp x, union ieee754sp y)
13{
14 int s;
15
16 COMPXSP;
17 COMPYSP;
18
19 EXPLODEXSP;
20 EXPLODEYSP;
21
22 ieee754_clearcx();
23
24 FLUSHXSP;
25 FLUSHYSP;
26
27 switch (CLPAIR(xc, yc)) {
28 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
29 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
30 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
31 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
32 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
33 return ieee754sp_nanxcpt(y);
34
35 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
36 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
37 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
38 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
39 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
40 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
41 return ieee754sp_nanxcpt(x);
42
43 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
44 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
45 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
46 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
47 return y;
48
49 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
50 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
51 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
52 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
53 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
54 return x;
55
56
57 /*
58 * Infinity handling
59 */
60 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
61 if (xs == ys)
62 return x;
63 ieee754_setcx(IEEE754_INVALID_OPERATION);
64 return ieee754sp_indef();
65
66 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
67 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
68 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
69 return y;
70
71 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
72 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
73 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
74 return x;
75
76 /*
77 * Zero handling
78 */
79 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
80 if (xs == ys)
81 return x;
82 else
83 return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
84
85 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
86 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
87 return x;
88
89 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
90 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
91 return y;
92
93 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
94 SPDNORMX;
95 /* fall through */
96
97 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
98 SPDNORMY;
99 break;
100
101 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
102 SPDNORMX;
103 break;
104
105 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
106 break;
107 }
108 assert(xm & SP_HIDDEN_BIT);
109 assert(ym & SP_HIDDEN_BIT);
110
111 /*
112 * Provide guard, round and stick bit space.
113 */
114 xm <<= 3;
115 ym <<= 3;
116
117 if (xe > ye) {
118 /*
119 * Have to shift y fraction right to align.
120 */
121 s = xe - ye;
122 ym = XSPSRS(ym, s);
123 ye += s;
124 } else if (ye > xe) {
125 /*
126 * Have to shift x fraction right to align.
127 */
128 s = ye - xe;
129 xm = XSPSRS(xm, s);
130 xe += s;
131 }
132 assert(xe == ye);
133 assert(xe <= SP_EMAX);
134
135 if (xs == ys) {
136 /*
137 * Generate 28 bit result of adding two 27 bit numbers
138 * leaving result in xm, xs and xe.
139 */
140 xm = xm + ym;
141
142 if (xm >> (SP_FBITS + 1 + 3)) { /* carry out */
143 SPXSRSX1();
144 }
145 } else {
146 if (xm >= ym) {
147 xm = xm - ym;
148 } else {
149 xm = ym - xm;
150 xs = ys;
151 }
152 if (xm == 0)
153 return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
154
155 /*
156 * Normalize in extended single precision
157 */
158 while ((xm >> (SP_FBITS + 3)) == 0) {
159 xm <<= 1;
160 xe--;
161 }
162 }
163
164 return ieee754sp_format(xs, xe, xm);
165}