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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 += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
- | |
51 | - | ||
52 | if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) { |
50 | if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) { |
53 | /* FIXME: underflow */ |
51 | /* FIXME: underflow */ |
54 | result.parts.exp = 0; |
52 | result.parts.exp = 0; |
55 | if ((cexp + FLOAT64_FRACTION_SIZE) < 0) { |
53 | if ((cexp + FLOAT64_FRACTION_SIZE + 1) < 0) { /* +1 is place for rounding */ |
56 | result.parts.fraction = 0; |
54 | result.parts.fraction = 0; |
57 | return result; |
55 | return result; |
58 | } |
56 | } |
59 | //cfrac >>= 1; |
57 | |
60 | while (cexp < 0) { |
58 | while (cexp < 0) { |
61 | cexp++; |
59 | cexp++; |
62 | cfrac >>= 1; |
60 | cfrac >>= 1; |
63 | } |
61 | } |
- | 62 | ||
- | 63 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
|
- | 64 | ||
- | 65 | if (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_HIDDEN_BIT_MASK - 1)))) { |
|
64 | 66 | ||
65 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
67 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
66 | - | ||
67 | return result; |
68 | return result; |
- | 69 | } |
|
- | 70 | } else { |
|
- | 71 | cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
|
68 | } |
72 | } |
69 | 73 | ||
70 | ++cexp; |
74 | ++cexp; |
71 | 75 | ||
72 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
76 | if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
73 | ++cexp; |
77 | ++cexp; |
74 | cfrac >>= 1; |
78 | cfrac >>= 1; |
75 | } |
79 | } |
76 | 80 | ||
77 | /* check overflow */ |
81 | /* check overflow */ |
78 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
82 | if (cexp >= FLOAT64_MAX_EXPONENT ) { |
79 | /* FIXME: overflow, return infinity */ |
83 | /* FIXME: overflow, return infinity */ |
80 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
84 | result.parts.exp = FLOAT64_MAX_EXPONENT; |
81 | result.parts.fraction = 0; |
85 | result.parts.fraction = 0; |
82 | return result; |
86 | return result; |
83 | } |
87 | } |
84 | 88 | ||
85 | result.parts.exp = (__u32)cexp; |
89 | result.parts.exp = (__u32)cexp; |
86 | 90 | ||
87 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
91 | result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
88 | 92 | ||
89 | return result; |
93 | return result; |
90 | } |
94 | } |
91 | 95 | ||
92 | 96 |