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| 647 | cejka | 1 | /* |
| 2 | * Copyright (C) 2005 Josef Cejka |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 697 | cejka | 29 | #include "sftypes.h" |
| 30 | #include "conversion.h" |
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| 31 | |||
| 32 | float64 convertFloat32ToFloat64(float32 a) |
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| 33 | { |
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| 34 | float64 result; |
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| 35 | __u64 mant; |
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| 36 | |||
| 37 | result.parts.sign = a.parts.sign; |
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| 38 | result.parts.mantisa = a.parts.mantisa; |
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| 39 | result.parts.mantisa <<= (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE ); |
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| 40 | |||
| 41 | if ((isFloat32Infinity(a))||(isFloat32NaN(a))) { |
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| 42 | result.parts.exp = 0x7FF; |
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| 43 | /* TODO; check if its correct for SigNaNs*/ |
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| 44 | return result; |
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| 45 | }; |
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| 46 | |||
| 47 | result.parts.exp = a.parts.exp + ( (int)FLOAT64_BIAS - FLOAT32_BIAS ); |
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| 48 | if (a.parts.exp == 0) { |
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| 49 | /* normalize denormalized numbers */ |
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| 50 | |||
| 51 | if (result.parts.mantisa == 0ll) { /* fix zero */ |
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| 52 | result.parts.exp = 0ll; |
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| 53 | return result; |
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| 54 | } |
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| 55 | |||
| 56 | mant = result.parts.mantisa; |
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| 57 | |||
| 58 | while (!(mant & (0x10000000000000ll))) { |
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| 59 | mant <<= 1; |
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| 60 | --result.parts.exp; |
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| 61 | }; |
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| 698 | cejka | 62 | |
| 63 | ++result.parts.exp; |
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| 697 | cejka | 64 | result.parts.mantisa = mant; |
| 65 | }; |
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| 66 | |||
| 67 | return result; |
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| 68 | |||
| 69 | }; |
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| 70 | |||
| 71 | float32 convertFloat64ToFloat32(float64 a) |
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| 72 | { |
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| 73 | float32 result; |
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| 74 | __s32 exp; |
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| 75 | __u64 mant; |
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| 76 | |||
| 77 | result.parts.sign = a.parts.sign; |
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| 78 | |||
| 79 | if (isFloat64NaN(a)) { |
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| 80 | |||
| 81 | result.parts.exp = 0xFF; |
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| 82 | |||
| 83 | if (isFloat64SigNaN(a)) { |
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| 84 | result.parts.mantisa = 0x800000; /* set first bit of mantisa nonzero */ |
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| 85 | return result; |
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| 86 | } |
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| 87 | |||
| 88 | result.parts.mantisa = 0x1; /* mantisa nonzero but its first bit is zero */ |
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| 89 | return result; |
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| 90 | }; |
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| 91 | |||
| 92 | if (isFloat64Infinity(a)) { |
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| 93 | result.parts.mantisa = 0; |
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| 94 | result.parts.exp = 0xFF; |
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| 95 | return result; |
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| 96 | }; |
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| 97 | |||
| 98 | exp = (int)a.parts.exp - FLOAT64_BIAS + FLOAT32_BIAS; |
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| 99 | |||
| 100 | if (exp >= 0xFF) { |
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| 101 | /*FIXME: overflow*/ |
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| 102 | result.parts.mantisa = 0; |
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| 103 | result.parts.exp = 0xFF; |
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| 104 | return result; |
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| 105 | |||
| 106 | } else if (exp <= 0 ) { |
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| 107 | |||
| 108 | /* underflow or denormalized */ |
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| 109 | |||
| 110 | result.parts.exp = 0; |
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| 111 | |||
| 112 | exp *= -1; |
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| 113 | if (exp > FLOAT32_MANTISA_SIZE ) { |
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| 114 | /* FIXME: underflow */ |
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| 115 | result.parts.mantisa = 0; |
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| 116 | return result; |
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| 117 | }; |
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| 118 | |||
| 119 | /* denormalized */ |
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| 120 | |||
| 698 | cejka | 121 | mant = a.parts.mantisa; |
| 697 | cejka | 122 | mant |= 0x10000000000000ll; /* denormalize and set hidden bit */ |
| 123 | |||
| 698 | cejka | 124 | mant >>= (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE + 1); |
| 125 | |||
| 697 | cejka | 126 | while (exp > 0) { |
| 127 | --exp; |
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| 128 | mant >>= 1; |
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| 129 | }; |
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| 130 | result.parts.mantisa = mant; |
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| 131 | |||
| 132 | return result; |
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| 133 | }; |
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| 134 | |||
| 135 | result.parts.exp = exp; |
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| 136 | result.parts.mantisa = a.parts.mantisa >> (FLOAT64_MANTISA_SIZE - FLOAT32_MANTISA_SIZE); |
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| 137 | return result; |
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| 138 | }; |
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| 139 |