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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 | /** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions |
32 | /** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions |
| 33 | * @param exp exponent with bias |
33 | * @param exp exponent with bias |
| 34 | * @param cfrac fraction shifted 10 places left with added hidden bit |
34 | * @param cfrac fraction shifted 10 places left with added hidden bit |
| 35 | * @return valied float64 |
35 | * @return valied float64 |
| 36 | */ |
36 | */ |
| 37 | float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign) |
37 | float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign) |
| 38 | { |
38 | { |
| 39 | float64 result; |
39 | float64 result; |
| 40 | 40 | ||
| 41 | result.parts.sign = sign; |
41 | result.parts.sign = sign; |
| 42 | 42 | ||
| 43 | /* find first nonzero digit and shift result and detect possibly underflow */ |
43 | /* 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 ) )))) { |
44 | while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) { |
| 45 | cexp--; |
45 | cexp--; |
| 46 | cfrac <<= 1; |
46 | cfrac <<= 1; |
| 47 | /* TODO: fix underflow */ |
47 | /* TODO: fix underflow */ |
| 48 | }; |
48 | }; |
| 49 | 49 | ||
| 50 | cfrac >>= 1; |
- | |
| 51 | ++cexp; |
- | |
| 52 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
50 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
| - | 51 | ||
| - | 52 | if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) { |
|
| - | 53 | /* FIXME: underflow */ |
|
| - | 54 | result.parts.exp = 0; |
|
| - | 55 | if ((cexp + FLOAT64_FRACTION_SIZE) < 0) { |
|
| - | 56 | result.parts.fraction = 0; |
|
| - | 57 | return result; |
|
| - | 58 | } |
|
| - | 59 | //cfrac >>= 1; |
|
| - | 60 | while (cexp < 0) { |
|
| - | 61 | cexp++; |
|
| - | 62 | cfrac >>= 1; |
|
| - | 63 | } |
|
| - | 64 | ||
| - | 65 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
|
| - | 66 | ||
| - | 67 | return result; |
|
| - | 68 | } |
|
| - | 69 | ||
| - | 70 | ++cexp; |
|
| 53 | 71 | ||
| 54 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
72 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
| 55 | ++cexp; |
73 | ++cexp; |
| 56 | cfrac >>= 1; |
74 | cfrac >>= 1; |
| 57 | } |
75 | } |
| 58 | 76 | ||
| 59 | /* check overflow */ |
77 | /* check overflow */ |
| 60 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
78 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
| 61 | /* FIXME: overflow, return infinity */ |
79 | /* FIXME: overflow, return infinity */ |
| 62 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
80 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
| 63 | result.parts.fraction = 0; |
81 | result.parts.fraction = 0; |
| 64 | return result; |
82 | return result; |
| 65 | } |
83 | } |
| 66 | 84 | ||
| 67 | if (cexp < 0) { |
- | |
| 68 | /* FIXME: underflow */ |
- | |
| 69 | result.parts.exp = 0; |
- | |
| 70 | if ((cexp + FLOAT64_FRACTION_SIZE) < 0) { |
- | |
| 71 | result.parts.fraction = 0; |
- | |
| 72 | return result; |
- | |
| 73 | } |
- | |
| 74 | cfrac >>= 1; |
- | |
| 75 | while (cexp < 0) { |
- | |
| 76 | cexp ++; |
- | |
| 77 | cfrac >>= 1; |
- | |
| 78 | } |
- | |
| 79 | return result; |
- | |
| 80 | - | ||
| 81 | } else { |
- | |
| 82 | cexp ++; /*normalized*/ |
- | |
| 83 | result.parts.exp = (__u32)cexp; |
85 | result.parts.exp = (__u32)cexp; |
| 84 | } |
- | |
| 85 | 86 | ||
| 86 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
87 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
| 87 | 88 | ||
| 88 | return result; |
89 | return result; |
| 89 | } |
90 | } |
| - | 91 | ||
| 90 | 92 | ||