source: mainline/softfloat/generic/add.c@ 1266543

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1266543 was 1266543, checked in by Josef Cejka <malyzelenyhnus@…>, 19 years ago

32 bit float division added.
Some small bugs fixed.
Code cleanup.
  • Property mode set to 100644
File size: 5.6 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 if ((a.parts.exp == FLOAT32_MAX_EXPONENT ) || (a.parts.exp < exp1)) {
122 /* overflow - set infinity as result */
123 a.parts.exp = FLOAT32_MAX_EXPONENT;
124 a.parts.fraction = 0;
125 return a;
126 }
127
128 a.parts.exp = exp1;
129
130 /*Clear hidden bit and shift */
131 a.parts.fraction = ((frac1 >> 6) & (~FLOAT32_HIDDEN_BIT_MASK)) ;
132 return a;
133}
134
135
136/** Add two Float64 numbers with same signs
137 */
138float64 addFloat64(float64 a, float64 b)
139{
140 int expdiff;
141 __u32 exp1, exp2;
142 __u64 frac1, frac2;
143
144 expdiff = a.parts.exp - b.parts.exp;
145 if (expdiff < 0) {
146 if (isFloat64NaN(b)) {
147 /* TODO: fix SigNaN */
148 if (isFloat64SigNaN(b)) {
149 };
150
151 return b;
152 };
153
154 /* b is infinity and a not */
155 if (b.parts.exp == FLOAT64_MAX_EXPONENT ) {
156 return b;
157 }
158
159 frac1 = b.parts.fraction;
160 exp1 = b.parts.exp;
161 frac2 = a.parts.fraction;
162 exp2 = a.parts.exp;
163 expdiff *= -1;
164 } else {
165 if (isFloat64NaN(a)) {
166 /* TODO: fix SigNaN */
167 if (isFloat64SigNaN(a) || isFloat64SigNaN(b)) {
168 };
169 return a;
170 };
171
172 /* a is infinity and b not */
173 if (a.parts.exp == FLOAT64_MAX_EXPONENT ) {
174 return a;
175 }
176
177 frac1 = a.parts.fraction;
178 exp1 = a.parts.exp;
179 frac2 = b.parts.fraction;
180 exp2 = b.parts.exp;
181 };
182
183 if (exp1 == 0) {
184 /* both are denormalized */
185 frac1 += frac2;
186 if (frac1 & FLOAT64_HIDDEN_BIT_MASK) {
187 /* result is not denormalized */
188 a.parts.exp = 1;
189 };
190 a.parts.fraction = frac1;
191 return a;
192 };
193
194 /* add hidden bit - frac1 is sure not denormalized */
195 frac1 |= FLOAT64_HIDDEN_BIT_MASK;
196
197 /* second operand ... */
198 if (exp2 == 0) {
199 /* ... is denormalized */
200 --expdiff;
201 } else {
202 /* is not denormalized */
203 frac2 |= FLOAT64_HIDDEN_BIT_MASK;
204 };
205
206 /* create some space for rounding */
207 frac1 <<= 6;
208 frac2 <<= 6;
209
210 if (expdiff < (FLOAT64_FRACTION_SIZE + 2) ) {
211 frac2 >>= expdiff;
212 frac1 += frac2;
213 };
214
215 if (frac1 & (FLOAT64_HIDDEN_BIT_MASK << 7) ) {
216 ++exp1;
217 frac1 >>= 1;
218 };
219
220 /* rounding - if first bit after fraction is set then round up */
221 frac1 += (0x1 << 5);
222
223 if (frac1 & (FLOAT64_HIDDEN_BIT_MASK << 7)) {
224 /* rounding overflow */
225 ++exp1;
226 frac1 >>= 1;
227 };
228
229 if ((a.parts.exp == FLOAT64_MAX_EXPONENT ) || (a.parts.exp < exp1)) {
230 /* overflow - set infinity as result */
231 a.parts.exp = FLOAT64_MAX_EXPONENT;
232 a.parts.fraction = 0;
233 return a;
234 }
235
236 a.parts.exp = exp1;
237 /*Clear hidden bit and shift */
238 a.parts.fraction = ( (frac1 >> 6 ) & (~FLOAT64_HIDDEN_BIT_MASK));
239 return a;
240}
241
242
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