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| Rev | Author | Line No. | Line |
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| 731 | 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 | |||
| 29 | #include<sftypes.h> |
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| 30 | #include<mul.h> |
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| 31 | #include<comparison.h> |
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| 32 | |||
| 33 | /** Multiply two 32 bit float numbers |
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| 34 | * |
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| 35 | */ |
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| 36 | float32 mulFloat32(float32 a, float32 b) |
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| 37 | { |
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| 38 | float32 result; |
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| 39 | __u64 mant1, mant2; |
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| 40 | __s32 exp; |
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| 41 | |||
| 42 | result.parts.sign = a.parts.sign ^ b.parts.sign; |
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| 43 | |||
| 44 | if ((isFloat32NaN(a))||(isFloat32NaN(b))) { |
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| 45 | /* TODO: fix SigNaNs */ |
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| 46 | if (isFloat32SigNaN(a)) { |
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| 47 | result.parts.mantisa = a.parts.mantisa; |
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| 48 | result.parts.exp = a.parts.exp; |
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| 49 | return result; |
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| 50 | }; |
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| 51 | if (isFloat32SigNaN(b)) { /* TODO: fix SigNaN */ |
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| 52 | result.parts.mantisa = b.parts.mantisa; |
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| 53 | result.parts.exp = b.parts.exp; |
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| 54 | return result; |
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| 55 | }; |
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| 56 | /* set NaN as result */ |
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| 57 | result.parts.mantisa = 0x1; |
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| 58 | result.parts.exp = 0xFF; |
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| 59 | return result; |
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| 60 | }; |
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| 61 | |||
| 62 | if (isFloat32Infinity(a)) { |
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| 63 | if (isFloat32Zero(b)) { |
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| 64 | /* FIXME: zero * infinity */ |
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| 65 | result.parts.mantisa = 0x1; |
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| 66 | result.parts.exp = 0xFF; |
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| 67 | return result; |
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| 68 | } |
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| 69 | result.parts.mantisa = a.parts.mantisa; |
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| 70 | result.parts.exp = a.parts.exp; |
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| 71 | return result; |
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| 72 | } |
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| 73 | |||
| 74 | if (isFloat32Infinity(b)) { |
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| 75 | if (isFloat32Zero(a)) { |
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| 76 | /* FIXME: zero * infinity */ |
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| 77 | result.parts.mantisa = 0x1; |
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| 78 | result.parts.exp = 0xFF; |
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| 79 | return result; |
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| 80 | } |
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| 81 | result.parts.mantisa = b.parts.mantisa; |
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| 82 | result.parts.exp = b.parts.exp; |
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| 83 | return result; |
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| 84 | } |
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| 85 | |||
| 86 | /* exp is signed so we can easy detect underflow */ |
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| 87 | exp = a.parts.exp + b.parts.exp; |
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| 88 | exp -= FLOAT32_BIAS; |
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| 89 | |||
| 90 | if (exp >= 0xFF ) { |
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| 91 | /* FIXME: overflow */ |
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| 92 | /* set infinity as result */ |
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| 93 | result.parts.mantisa = 0x0; |
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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 | if (exp < 0) { |
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| 99 | /* FIXME: underflow */ |
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| 100 | /* return signed zero */ |
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| 101 | result.parts.mantisa = 0x0; |
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| 102 | result.parts.exp = 0x0; |
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| 103 | return result; |
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| 104 | }; |
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| 105 | |||
| 106 | mant1 = a.parts.mantisa; |
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| 107 | if (a.parts.exp>0) { |
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| 108 | mant1 |= 0x800000; |
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| 109 | } else { |
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| 110 | ++exp; |
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| 111 | }; |
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| 112 | |||
| 113 | mant2 = b.parts.mantisa; |
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| 114 | if (b.parts.exp>0) { |
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| 115 | mant2 |= 0x800000; |
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| 116 | } else { |
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| 117 | ++exp; |
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| 118 | }; |
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| 119 | |||
| 120 | mant1 <<= 1; /* one bit space for rounding */ |
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| 121 | |||
| 122 | mant1 = mant1 * mant2; |
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| 123 | /* round and return */ |
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| 124 | |||
| 125 | while ((exp < 0xFF )&&(mant1 > 0x1FFFFFF )) { |
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| 126 | /* 0xFFFFFF is 23 bits of mantisa + one more for hidden bit (all shifted 1 bit left)*/ |
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| 127 | ++exp; |
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| 128 | mant1 >>= 1; |
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| 129 | }; |
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| 130 | |||
| 131 | /* rounding */ |
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| 132 | //++mant1; /* FIXME: not works - without it is ok */ |
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| 133 | mant1 >>= 1; /* shift off rounding space */ |
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| 134 | |||
| 135 | if ((exp < 0xFF )&&(mant1 > 0xFFFFFF )) { |
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| 136 | ++exp; |
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| 137 | mant1 >>= 1; |
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| 138 | }; |
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| 139 | |||
| 140 | if (exp >= 0xFF ) { |
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| 141 | /* TODO: fix overflow */ |
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| 142 | /* return infinity*/ |
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| 143 | result.parts.exp = 0xFF; |
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| 144 | result.parts.mantisa = 0x0; |
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| 145 | return result; |
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| 146 | } |
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| 147 | |||
| 148 | exp -= FLOAT32_MANTISA_SIZE; |
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| 149 | |||
| 150 | if (exp <= FLOAT32_MANTISA_SIZE) { |
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| 151 | /* denormalized number */ |
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| 152 | mant1 >>= 1; /* denormalize */ |
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| 153 | while ((mant1 > 0) && (exp < 0)) { |
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| 154 | mant1 >>= 1; |
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| 155 | ++exp; |
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| 156 | }; |
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| 157 | if (mant1 == 0) { |
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| 158 | /* FIXME : underflow */ |
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| 159 | result.parts.exp = 0; |
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| 160 | result.parts.mantisa = 0; |
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| 161 | return result; |
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| 162 | }; |
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| 163 | }; |
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| 164 | result.parts.exp = exp; |
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| 165 | result.parts.mantisa = mant1 & 0x7FFFFF; |
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| 166 | |||
| 167 | return result; |
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| 168 | |||
| 169 | } |
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| 170 | |||
| 171 | |||
| 172 |