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1 | /* |
1 | /* |
2 | * Copyright (C) 2005 Josef Cejka |
2 | * Copyright (C) 2005 Josef Cejka |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
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 |
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. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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 |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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 |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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 |
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. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | #include<sftypes.h> |
29 | #include<sftypes.h> |
30 | #include<common.h> |
30 | #include<common.h> |
31 | 31 | ||
- | 32 | /* Table for fast leading zeroes counting */ |
|
- | 33 | char zeroTable[256] = { |
|
- | 34 | 8, 7, 7, 6, 6, 6, 6, 4, 4, 4, 4, 4, 4, 4, 4, \ |
|
- | 35 | 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, \ |
|
- | 36 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, \ |
|
- | 37 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, \ |
|
- | 38 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \ |
|
- | 39 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \ |
|
- | 40 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \ |
|
- | 41 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \ |
|
- | 42 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 43 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 44 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 45 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 46 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 47 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 48 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \ |
|
- | 49 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 |
|
- | 50 | }; |
|
- | 51 | ||
- | 52 | ||
- | 53 | ||
32 | /** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions |
54 | /** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions |
33 | * @param exp exponent with bias |
55 | * @param exp exponent with bias |
34 | * @param cfrac fraction shifted 10 places left with added hidden bit |
56 | * @param cfrac fraction shifted 10 places left with added hidden bit |
35 | * @return valied float64 |
57 | * @return valied float64 |
36 | */ |
58 | */ |
37 | float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign) |
59 | float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign) |
38 | { |
60 | { |
39 | float64 result; |
61 | float64 result; |
40 | 62 | ||
41 | result.parts.sign = sign; |
63 | result.parts.sign = sign; |
42 | 64 | ||
43 | /* find first nonzero digit and shift result and detect possibly underflow */ |
65 | /* find first nonzero digit and shift result and detect possibly underflow */ |
44 | while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) { |
66 | while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) { |
45 | cexp--; |
67 | cexp--; |
46 | cfrac <<= 1; |
68 | cfrac <<= 1; |
47 | /* TODO: fix underflow */ |
69 | /* TODO: fix underflow */ |
48 | }; |
70 | }; |
49 | 71 | ||
50 | if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) { |
72 | if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) { |
51 | /* FIXME: underflow */ |
73 | /* FIXME: underflow */ |
52 | result.parts.exp = 0; |
74 | result.parts.exp = 0; |
53 | if ((cexp + FLOAT64_FRACTION_SIZE + 1) < 0) { /* +1 is place for rounding */ |
75 | if ((cexp + FLOAT64_FRACTION_SIZE + 1) < 0) { /* +1 is place for rounding */ |
54 | result.parts.fraction = 0; |
76 | result.parts.fraction = 0; |
55 | return result; |
77 | return result; |
56 | } |
78 | } |
57 | 79 | ||
58 | while (cexp < 0) { |
80 | while (cexp < 0) { |
59 | cexp++; |
81 | cexp++; |
60 | cfrac >>= 1; |
82 | cfrac >>= 1; |
61 | } |
83 | } |
62 | 84 | ||
63 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
85 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
64 | 86 | ||
65 | if (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_HIDDEN_BIT_MASK - 1)))) { |
87 | if (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))) { |
66 | 88 | ||
67 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
89 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
68 | return result; |
90 | return result; |
69 | } |
91 | } |
70 | } else { |
92 | } else { |
71 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
93 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
72 | } |
94 | } |
73 | 95 | ||
74 | ++cexp; |
96 | ++cexp; |
75 | 97 | ||
76 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
98 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
77 | ++cexp; |
99 | ++cexp; |
78 | cfrac >>= 1; |
100 | cfrac >>= 1; |
79 | } |
101 | } |
80 | 102 | ||
81 | /* check overflow */ |
103 | /* check overflow */ |
82 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
104 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
83 | /* FIXME: overflow, return infinity */ |
105 | /* FIXME: overflow, return infinity */ |
84 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
106 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
85 | result.parts.fraction = 0; |
107 | result.parts.fraction = 0; |
86 | return result; |
108 | return result; |
87 | } |
109 | } |
88 | 110 | ||
89 | result.parts.exp = (__u32)cexp; |
111 | result.parts.exp = (__u32)cexp; |
90 | 112 | ||
91 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
113 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
92 | 114 | ||
93 | return result; |
115 | return result; |
94 | } |
116 | } |
- | 117 | ||
- | 118 | /** Counts leading zeroes in 64bit unsigned integer |
|
- | 119 | * @param i |
|
- | 120 | */ |
|
- | 121 | int countZeroes64(__u64 i) |
|
- | 122 | { |
|
- | 123 | int j; |
|
- | 124 | for (j =0; j < 64; j += 8) { |
|
- | 125 | if ( i & (0xFFll << (56 - j))) { |
|
- | 126 | return (j + countZeroes8(i >> (56 - j))); |
|
- | 127 | } |
|
- | 128 | } |
|
- | 129 | ||
- | 130 | return 64; |
|
- | 131 | } |
|
- | 132 | ||
- | 133 | /** Counts leading zeroes in 32bit unsigned integer |
|
- | 134 | * @param i |
|
- | 135 | */ |
|
- | 136 | int countZeroes32(__u32 i) |
|
- | 137 | { |
|
- | 138 | int j; |
|
- | 139 | for (j =0; j < 32; j += 8) { |
|
- | 140 | if ( i & (0xFF << (24 - j))) { |
|
- | 141 | return (j + countZeroes8(i >> (24 - j))); |
|
- | 142 | } |
|
- | 143 | } |
|
- | 144 | ||
- | 145 | return 32; |
|
- | 146 | } |
|
- | 147 | ||
- | 148 | /** Counts leading zeroes in byte |
|
- | 149 | * @param i |
|
- | 150 | */ |
|
- | 151 | int countZeroes8(__u8 i) |
|
- | 152 | { |
|
- | 153 | return zeroTable[i]; |
|
- | 154 | } |
|
- | 155 | ||
- | 156 | /** Round and normalize number expressed by exponent and fraction with first bit (equal to hidden bit) at 30. bit |
|
- | 157 | * @param exp exponent |
|
- | 158 | * @param fraction part with hidden bit shifted to 30. bit |
|
- | 159 | */ |
|
- | 160 | void roundFloat32(__s32 *exp, __u32 *fraction) |
|
- | 161 | { |
|
- | 162 | /* rounding - if first bit after fraction is set then round up */ |
|
- | 163 | (*fraction) += (0x1 << 6); |
|
- | 164 | ||
- | 165 | if ((*fraction) & (FLOAT32_HIDDEN_BIT_MASK << 8)) { |
|
- | 166 | /* rounding overflow */ |
|
- | 167 | ++(*exp); |
|
- | 168 | (*fraction) >>= 1; |
|
- | 169 | }; |
|
- | 170 | ||
- | 171 | if (((*exp) >= FLOAT32_MAX_EXPONENT ) || ((*exp) < 0)) { |
|
- | 172 | /* overflow - set infinity as result */ |
|
- | 173 | (*exp) = FLOAT32_MAX_EXPONENT; |
|
- | 174 | (*fraction) = 0; |
|
- | 175 | return; |
|
- | 176 | } |
|
- | 177 | ||
- | 178 | return; |
|
- | 179 | } |
|
- | 180 | ||
- | 181 | /** Round and normalize number expressed by exponent and fraction with first bit (equal to hidden bit) at 62. bit |
|
- | 182 | * @param exp exponent |
|
- | 183 | * @param fraction part with hidden bit shifted to 62. bit |
|
- | 184 | */ |
|
- | 185 | void roundFloat64(__s32 *exp, __u64 *fraction) |
|
- | 186 | { |
|
- | 187 | /* rounding - if first bit after fraction is set then round up */ |
|
- | 188 | (*fraction) += (0x1 << 9); |
|
- | 189 | ||
- | 190 | if ((*fraction) & (FLOAT64_HIDDEN_BIT_MASK << 11)) { |
|
- | 191 | /* rounding overflow */ |
|
- | 192 | ++(*exp); |
|
- | 193 | (*fraction) >>= 1; |
|
- | 194 | }; |
|
- | 195 | ||
- | 196 | if (((*exp) >= FLOAT64_MAX_EXPONENT ) || ((*exp) < 0)) { |
|
- | 197 | /* overflow - set infinity as result */ |
|
- | 198 | (*exp) = FLOAT64_MAX_EXPONENT; |
|
- | 199 | (*fraction) = 0; |
|
- | 200 | return; |
|
- | 201 | } |
|
- | 202 | ||
- | 203 | return; |
|
- | 204 | } |
|
95 | 205 | ||
96 | 206 |