source: mainline/softfloat/generic/add.c@ e979fea

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since e979fea was e6a40ac, checked in by Josef Cejka <malyzelenyhnus@…>, 19 years ago

64bit float division added.
Some bugs fixed in 64bit multiplication and adding.
  • Property mode set to 100644
File size: 5.5 KB
Line 
1/*
2 * Copyright (C) 2005 Josef Cejka
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include<sftypes.h>
30#include<add.h>
31#include<comparison.h>
32
33/** Add two Float32 numbers with same signs
34 */
35float32 addFloat32(float32 a, float32 b)
36{
37 int expdiff;
38 __u32 exp1, exp2,frac1, frac2;
39
40 expdiff = a.parts.exp - b.parts.exp;
41 if (expdiff < 0) {
42 if (isFloat32NaN(b)) {
43 /* TODO: fix SigNaN */
44 if (isFloat32SigNaN(b)) {
45 };
46
47 return b;
48 };
49
50 if (b.parts.exp == FLOAT32_MAX_EXPONENT) {
51 return b;
52 }
53
54 frac1 = b.parts.fraction;
55 exp1 = b.parts.exp;
56 frac2 = a.parts.fraction;
57 exp2 = a.parts.exp;
58 expdiff *= -1;
59 } else {
60 if ((isFloat32NaN(a)) || (isFloat32NaN(b))) {
61 /* TODO: fix SigNaN */
62 if (isFloat32SigNaN(a) || isFloat32SigNaN(b)) {
63 };
64 return (isFloat32NaN(a)?a:b);
65 };
66
67 if (a.parts.exp == FLOAT32_MAX_EXPONENT) {
68 return a;
69 }
70
71 frac1 = a.parts.fraction;
72 exp1 = a.parts.exp;
73 frac2 = b.parts.fraction;
74 exp2 = b.parts.exp;
75 };
76
77 if (exp1 == 0) {
78 /* both are denormalized */
79 frac1 += frac2;
80 if (frac1 & FLOAT32_HIDDEN_BIT_MASK ) {
81 /* result is not denormalized */
82 a.parts.exp = 1;
83 };
84 a.parts.fraction = frac1;
85 return a;
86 };
87
88 frac1 |= FLOAT32_HIDDEN_BIT_MASK; /* add hidden bit */
89
90 if (exp2 == 0) {
91 /* second operand is denormalized */
92 --expdiff;
93 } else {
94 /* add hidden bit to second operand */
95 frac2 |= FLOAT32_HIDDEN_BIT_MASK;
96 };
97
98 /* create some space for rounding */
99 frac1 <<= 6;
100 frac2 <<= 6;
101
102 if (expdiff < (FLOAT32_FRACTION_SIZE + 2) ) {
103 frac2 >>= expdiff;
104 frac1 += frac2;
105 };
106
107 if (frac1 & (FLOAT32_HIDDEN_BIT_MASK << 7) ) {
108 ++exp1;
109 frac1 >>= 1;
110 };
111
112 /* rounding - if first bit after fraction is set then round up */
113 frac1 += (0x1 << 5);
114
115 if (frac1 & (FLOAT32_HIDDEN_BIT_MASK << 7)) {
116 /* rounding overflow */
117 ++exp1;
118 frac1 >>= 1;
119 };
120
121
122 if ((exp1 == FLOAT32_MAX_EXPONENT ) || (exp2 > exp1)) {
123 /* overflow - set infinity as result */
124 a.parts.exp = FLOAT32_MAX_EXPONENT;
125 a.parts.fraction = 0;
126 return a;
127 }
128
129 a.parts.exp = exp1;
130
131 /*Clear hidden bit and shift */
132 a.parts.fraction = ((frac1 >> 6) & (~FLOAT32_HIDDEN_BIT_MASK)) ;
133 return a;
134}
135
136
137/** Add two Float64 numbers with same signs
138 */
139float64 addFloat64(float64 a, float64 b)
140{
141 int expdiff;
142 __u32 exp1, exp2;
143 __u64 frac1, frac2;
144
145 expdiff = a.parts.exp - b.parts.exp;
146 if (expdiff < 0) {
147 if (isFloat64NaN(b)) {
148 /* TODO: fix SigNaN */
149 if (isFloat64SigNaN(b)) {
150 };
151
152 return b;
153 };
154
155 /* b is infinity and a not */
156 if (b.parts.exp == FLOAT64_MAX_EXPONENT ) {
157 return b;
158 }
159
160 frac1 = b.parts.fraction;
161 exp1 = b.parts.exp;
162 frac2 = a.parts.fraction;
163 exp2 = a.parts.exp;
164 expdiff *= -1;
165 } else {
166 if (isFloat64NaN(a)) {
167 /* TODO: fix SigNaN */
168 if (isFloat64SigNaN(a) || isFloat64SigNaN(b)) {
169 };
170 return a;
171 };
172
173 /* a is infinity and b not */
174 if (a.parts.exp == FLOAT64_MAX_EXPONENT ) {
175 return a;
176 }
177
178 frac1 = a.parts.fraction;
179 exp1 = a.parts.exp;
180 frac2 = b.parts.fraction;
181 exp2 = b.parts.exp;
182 };
183
184 if (exp1 == 0) {
185 /* both are denormalized */
186 frac1 += frac2;
187 if (frac1 & FLOAT64_HIDDEN_BIT_MASK) {
188 /* result is not denormalized */
189 a.parts.exp = 1;
190 };
191 a.parts.fraction = frac1;
192 return a;
193 };
194
195 /* add hidden bit - frac1 is sure not denormalized */
196 frac1 |= FLOAT64_HIDDEN_BIT_MASK;
197
198 /* second operand ... */
199 if (exp2 == 0) {
200 /* ... is denormalized */
201 --expdiff;
202 } else {
203 /* is not denormalized */
204 frac2 |= FLOAT64_HIDDEN_BIT_MASK;
205 };
206
207 /* create some space for rounding */
208 frac1 <<= 6;
209 frac2 <<= 6;
210
211 if (expdiff < (FLOAT64_FRACTION_SIZE + 2) ) {
212 frac2 >>= expdiff;
213 frac1 += frac2;
214 };
215
216 if (frac1 & (FLOAT64_HIDDEN_BIT_MASK << 7) ) {
217 ++exp1;
218 frac1 >>= 1;
219 };
220
221 /* rounding - if first bit after fraction is set then round up */
222 frac1 += (0x1 << 5);
223
224 if (frac1 & (FLOAT64_HIDDEN_BIT_MASK << 7)) {
225 /* rounding overflow */
226 ++exp1;
227 frac1 >>= 1;
228 };
229
230 if ((a.parts.exp == FLOAT64_MAX_EXPONENT ) || (a.parts.exp < exp1)) {
231 /* overflow - set infinity as result */
232 a.parts.exp = FLOAT64_MAX_EXPONENT;
233 a.parts.fraction = 0;
234 return a;
235 }
236
237 a.parts.exp = exp1;
238 /*Clear hidden bit and shift */
239 a.parts.fraction = ( (frac1 >> 6 ) & (~FLOAT64_HIDDEN_BIT_MASK));
240 return a;
241}
242
243
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