1 2/*============================================================================ 3 4This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic 5Package, Release 3e, by John R. Hauser. 6 7Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of 8California. All rights reserved. 9 10Redistribution and use in source and binary forms, with or without 11modification, are permitted provided that the following conditions are met: 12 13 1. Redistributions of source code must retain the above copyright notice, 14 this list of conditions, and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright notice, 17 this list of conditions, and the following disclaimer in the documentation 18 and/or other materials provided with the distribution. 19 20 3. Neither the name of the University nor the names of its contributors may 21 be used to endorse or promote products derived from this software without 22 specific prior written permission. 23 24THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY 25EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 26WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE 27DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY 28DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 29(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 31ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 35=============================================================================*/ 36 37#include <stdbool.h> 38#include <stdint.h> 39#include "platform.h" 40#include "internals.h" 41#include "specialize.h" 42#include "softfloat.h" 43 44extern const uint16_t softfloat_approxRecip_1k0s[]; 45extern const uint16_t softfloat_approxRecip_1k1s[]; 46 47float16_t f16_div( float16_t a, float16_t b ) 48{ 49 union ui16_f16 uA; 50 uint_fast16_t uiA; 51 bool signA; 52 int_fast8_t expA; 53 uint_fast16_t sigA; 54 union ui16_f16 uB; 55 uint_fast16_t uiB; 56 bool signB; 57 int_fast8_t expB; 58 uint_fast16_t sigB; 59 bool signZ; 60 struct exp8_sig16 normExpSig; 61 int_fast8_t expZ; 62#ifdef SOFTFLOAT_FAST_DIV32TO16 63 uint_fast32_t sig32A; 64 uint_fast16_t sigZ; 65#else 66 int index; 67 uint16_t r0; 68 uint_fast16_t sigZ, rem; 69#endif 70 uint_fast16_t uiZ; 71 union ui16_f16 uZ; 72 73 /*------------------------------------------------------------------------ 74 *------------------------------------------------------------------------*/ 75 uA.f = a; 76 uiA = uA.ui; 77 signA = signF16UI( uiA ); 78 expA = expF16UI( uiA ); 79 sigA = fracF16UI( uiA ); 80 uB.f = b; 81 uiB = uB.ui; 82 signB = signF16UI( uiB ); 83 expB = expF16UI( uiB ); 84 sigB = fracF16UI( uiB ); 85 signZ = signA ^ signB; 86 /*------------------------------------------------------------------------ 87 *------------------------------------------------------------------------*/ 88 if ( expA == 0x1F ) { 89 if ( sigA ) goto propagateNaN; 90 if ( expB == 0x1F ) { 91 if ( sigB ) goto propagateNaN; 92 goto invalid; 93 } 94 goto infinity; 95 } 96 if ( expB == 0x1F ) { 97 if ( sigB ) goto propagateNaN; 98 goto zero; 99 } 100 /*------------------------------------------------------------------------ 101 *------------------------------------------------------------------------*/ 102 if ( ! expB ) { 103 if ( ! sigB ) { 104 if ( ! (expA | sigA) ) goto invalid; 105 softfloat_raiseFlags( softfloat_flag_infinite ); 106 goto infinity; 107 } 108 normExpSig = softfloat_normSubnormalF16Sig( sigB ); 109 expB = normExpSig.exp; 110 sigB = normExpSig.sig; 111 } 112 if ( ! expA ) { 113 if ( ! sigA ) goto zero; 114 normExpSig = softfloat_normSubnormalF16Sig( sigA ); 115 expA = normExpSig.exp; 116 sigA = normExpSig.sig; 117 } 118 /*------------------------------------------------------------------------ 119 *------------------------------------------------------------------------*/ 120 expZ = expA - expB + 0xE; 121 sigA |= 0x0400; 122 sigB |= 0x0400; 123#ifdef SOFTFLOAT_FAST_DIV32TO16 124 if ( sigA < sigB ) { 125 --expZ; 126 sig32A = (uint_fast32_t) sigA<<15; 127 } else { 128 sig32A = (uint_fast32_t) sigA<<14; 129 } 130 sigZ = sig32A / sigB; 131 if ( ! (sigZ & 7) ) sigZ |= ((uint_fast32_t) sigB * sigZ != sig32A); 132#else 133 if ( sigA < sigB ) { 134 --expZ; 135 sigA <<= 5; 136 } else { 137 sigA <<= 4; 138 } 139 index = sigB>>6 & 0xF; 140 r0 = softfloat_approxRecip_1k0s[index] 141 - (((uint_fast32_t) softfloat_approxRecip_1k1s[index] 142 * (sigB & 0x3F)) 143 >>10); 144 sigZ = ((uint_fast32_t) sigA * r0)>>16; 145 rem = (sigA<<10) - sigZ * sigB; 146 sigZ += (rem * (uint_fast32_t) r0)>>26; 147 /*------------------------------------------------------------------------ 148 *------------------------------------------------------------------------*/ 149 ++sigZ; 150 if ( ! (sigZ & 7) ) { 151 sigZ &= ~1; 152 rem = (sigA<<10) - sigZ * sigB; 153 if ( rem & 0x8000 ) { 154 sigZ -= 2; 155 } else { 156 if ( rem ) sigZ |= 1; 157 } 158 } 159#endif 160 return softfloat_roundPackToF16( signZ, expZ, sigZ ); 161 /*------------------------------------------------------------------------ 162 *------------------------------------------------------------------------*/ 163 propagateNaN: 164 uiZ = softfloat_propagateNaNF16UI( uiA, uiB ); 165 goto uiZ; 166 /*------------------------------------------------------------------------ 167 *------------------------------------------------------------------------*/ 168 invalid: 169 softfloat_raiseFlags( softfloat_flag_invalid ); 170 uiZ = defaultNaNF16UI; 171 goto uiZ; 172 /*------------------------------------------------------------------------ 173 *------------------------------------------------------------------------*/ 174 infinity: 175 uiZ = packToF16UI( signZ, 0x1F, 0 ); 176 goto uiZ; 177 /*------------------------------------------------------------------------ 178 *------------------------------------------------------------------------*/ 179 zero: 180 uiZ = packToF16UI( signZ, 0, 0 ); 181 uiZ: 182 uZ.ui = uiZ; 183 return uZ.f; 184 185} 186 187