| 1 | /*
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| 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 |
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| 29 | #include<sftypes.h>
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| 30 | #include<add.h>
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| 31 | #include<comparison.h>
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| 32 |
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| 33 | float32 divFloat32(float32 a, float32 b)
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| 34 | {
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| 35 | float32 result;
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| 36 | __s32 aexp, bexp, cexp;
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| 37 | __u64 afrac, bfrac, cfrac;
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| 38 |
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| 39 | result.parts.sign = a.parts.sign ^ b.parts.sign;
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| 40 |
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| 41 | if (isFloat32NaN(a)) {
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| 42 | if (isFloat32SigNaN(a)) {
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| 43 | /*FIXME: SigNaN*/
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| 44 | }
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| 45 | /*NaN*/
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| 46 | return a;
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| 47 | }
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| 48 |
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| 49 | if (isFloat32NaN(b)) {
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| 50 | if (isFloat32SigNaN(b)) {
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| 51 | /*FIXME: SigNaN*/
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| 52 | }
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| 53 | /*NaN*/
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| 54 | return b;
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| 55 | }
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| 56 |
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| 57 | if (isFloat32Infinity(a)) {
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| 58 | if (isFloat32Infinity(b)) {
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| 59 | /*FIXME: inf / inf */
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| 60 | result.binary = FLOAT32_NAN;
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| 61 | return result;
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| 62 | }
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| 63 | /* inf / num */
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| 64 | result.parts.exp = a.parts.exp;
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| 65 | result.parts.fraction = a.parts.fraction;
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| 66 | return result;
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| 67 | }
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| 68 |
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| 69 | if (isFloat32Infinity(b)) {
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| 70 | if (isFloat32Zero(a)) {
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| 71 | /* FIXME 0 / inf */
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| 72 | result.parts.exp = 0;
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| 73 | result.parts.fraction = 0;
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| 74 | return result;
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| 75 | }
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| 76 | /* FIXME: num / inf*/
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| 77 | result.parts.exp = 0;
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| 78 | result.parts.fraction = 0;
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| 79 | return result;
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| 80 | }
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| 81 |
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| 82 | if (isFloat32Zero(b)) {
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| 83 | if (isFloat32Zero(a)) {
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| 84 | /*FIXME: 0 / 0*/
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| 85 | result.binary = FLOAT32_NAN;
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| 86 | return result;
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| 87 | }
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| 88 | /* FIXME: division by zero */
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| 89 | result.parts.exp = 0;
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| 90 | result.parts.fraction = 0;
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| 91 | return result;
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| 92 | }
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| 93 |
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| 94 |
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| 95 | afrac = a.parts.fraction;
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| 96 | aexp = a.parts.exp;
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| 97 | bfrac = b.parts.fraction;
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| 98 | bexp = b.parts.exp;
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| 99 |
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| 100 | /* denormalized numbers */
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| 101 | if (aexp == 0) {
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| 102 | if (afrac == 0) {
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| 103 | result.parts.exp = 0;
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| 104 | result.parts.fraction = 0;
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| 105 | return result;
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| 106 | }
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| 107 | /* normalize it*/
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| 108 |
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| 109 | afrac <<= 1;
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| 110 | /* afrac is nonzero => it must stop */
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| 111 | while (! (afrac & FLOAT32_HIDDEN_BIT_MASK) ) {
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| 112 | afrac <<= 1;
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| 113 | aexp--;
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| 114 | }
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| 115 | }
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| 116 |
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| 117 | if (bexp == 0) {
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| 118 | bfrac <<= 1;
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| 119 | /* bfrac is nonzero => it must stop */
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| 120 | while (! (bfrac & FLOAT32_HIDDEN_BIT_MASK) ) {
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| 121 | bfrac <<= 1;
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| 122 | bexp--;
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| 123 | }
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| 124 | }
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| 125 |
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| 126 | afrac = (afrac | FLOAT32_HIDDEN_BIT_MASK ) << (32 - FLOAT32_FRACTION_SIZE - 1 );
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| 127 | bfrac = (bfrac | FLOAT32_HIDDEN_BIT_MASK ) << (32 - FLOAT32_FRACTION_SIZE );
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| 128 |
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| 129 | if ( bfrac <= (afrac << 1) ) {
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| 130 | afrac >>= 1;
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| 131 | aexp++;
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| 132 | }
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| 133 |
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| 134 | cexp = aexp - bexp + FLOAT32_BIAS - 2;
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| 135 |
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| 136 | cfrac = (afrac << 32) / bfrac;
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| 137 | if (( cfrac & 0x3F ) == 0) {
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| 138 | cfrac |= ( bfrac * cfrac != afrac << 32 );
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| 139 | }
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| 140 |
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| 141 | /* pack and round */
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| 142 |
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| 143 | /* TODO: find first nonzero digit and shift result and detect possibly underflow */
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| 144 | while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT32_HIDDEN_BIT_MASK << 7 )))) {
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| 145 | cexp--;
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| 146 | cfrac <<= 1;
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| 147 | /* TODO: fix underflow */
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| 148 | };
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| 149 |
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| 150 |
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| 151 | cfrac += (0x1 << 6); /* FIXME: 7 is not sure*/
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| 152 |
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| 153 | if (cfrac & (FLOAT32_HIDDEN_BIT_MASK << 7)) {
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| 154 | ++cexp;
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| 155 | cfrac >>= 1;
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| 156 | }
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| 157 |
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| 158 | /* check overflow */
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| 159 | if (cexp >= FLOAT32_MAX_EXPONENT ) {
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| 160 | /* FIXME: overflow, return infinity */
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| 161 | result.parts.exp = FLOAT32_MAX_EXPONENT;
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| 162 | result.parts.fraction = 0;
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| 163 | return result;
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| 164 | }
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| 165 |
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| 166 | if (cexp < 0) {
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| 167 | /* FIXME: underflow */
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| 168 | result.parts.exp = 0;
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| 169 | if ((cexp + FLOAT32_FRACTION_SIZE) < 0) {
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| 170 | result.parts.fraction = 0;
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| 171 | return result;
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| 172 | }
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| 173 | cfrac >>= 1;
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| 174 | while (cexp < 0) {
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| 175 | cexp ++;
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| 176 | cfrac >>= 1;
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| 177 | }
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| 178 |
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| 179 | } else {
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| 180 | result.parts.exp = (__u32)cexp;
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| 181 | }
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| 182 |
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| 183 | result.parts.fraction = ((cfrac >> 6) & (~FLOAT32_HIDDEN_BIT_MASK));
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| 184 |
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| 185 | return result;
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| 186 | }
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| 187 |
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