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author | Palmer Dabbelt <palmer@dabbelt.com> | 2018-07-11 01:31:05 -0700 |
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committer | GitHub <noreply@github.com> | 2018-07-11 01:31:05 -0700 |
commit | 537ae11ae506b6fa6c4dd9dc37c9cc818af84027 (patch) | |
tree | 392295f5f2f696eb647189eab939bdf45cbc7ab1 /softfloat/f64_sqrt.c | |
parent | 63241292c9f4aa0e36d6f5482b6e378a48256002 (diff) | |
parent | 5cd8d2b93fad2011fdf8f49a263d77697af35b32 (diff) | |
download | riscv-pk-537ae11ae506b6fa6c4dd9dc37c9cc818af84027.zip riscv-pk-537ae11ae506b6fa6c4dd9dc37c9cc818af84027.tar.gz riscv-pk-537ae11ae506b6fa6c4dd9dc37c9cc818af84027.tar.bz2 |
Merge pull request #113 from riscv/license
Upgrade SoftFloat
Diffstat (limited to 'softfloat/f64_sqrt.c')
-rw-r--r--[-rwxr-xr-x] | softfloat/f64_sqrt.c | 207 |
1 files changed, 132 insertions, 75 deletions
diff --git a/softfloat/f64_sqrt.c b/softfloat/f64_sqrt.c index d446bc4..f12acdb 100755..100644 --- a/softfloat/f64_sqrt.c +++ b/softfloat/f64_sqrt.c @@ -1,76 +1,133 @@ -// See LICENSE.SoftFloat for license details. -
-#include <stdbool.h>
-#include <stdint.h>
-#include "platform.h"
-#include "primitives.h"
-#include "internals.h"
-#include "specialize.h"
-#include "softfloat.h"
-
-float64_t f64_sqrt( float64_t a )
-{
- union ui64_f64 uA;
- uint_fast64_t uiA;
- bool signA;
- int_fast16_t expA;
- uint_fast64_t sigA, uiZ;
- struct exp16_sig64 normExpSig;
- int_fast16_t expZ;
- uint_fast32_t sigZ32;
- uint_fast64_t sigZ;
- struct uint128 term, rem;
- union ui64_f64 uZ;
-
- uA.f = a;
- uiA = uA.ui;
- signA = signF64UI( uiA );
- expA = expF64UI( uiA );
- sigA = fracF64UI( uiA );
- if ( expA == 0x7FF ) {
- if ( sigA ) {
- uiZ = softfloat_propagateNaNF64UI( uiA, 0 );
- goto uiZ;
- }
- if ( ! signA ) return a;
- goto invalid;
- }
- if ( signA ) {
- if ( ! ( expA | sigA ) ) return a;
- goto invalid;
- }
- if ( ! expA ) {
- if ( ! sigA ) return a;
- normExpSig = softfloat_normSubnormalF64Sig( sigA );
- expA = normExpSig.exp;
- sigA = normExpSig.sig;
- }
- expZ = ( ( expA - 0x3FF )>>1 ) + 0x3FE;
- sigA |= UINT64_C( 0x0010000000000000 );
- sigZ32 = softfloat_estimateSqrt32( expA, sigA>>21 );
- sigA <<= 9 - ( expA & 1 );
- sigZ =
- softfloat_estimateDiv128To64( sigA, 0, (uint_fast64_t) sigZ32<<32 )
- + ( (uint_fast64_t) sigZ32<<30 );
- if ( ( sigZ & 0x1FF ) <= 5 ) {
- term = softfloat_mul64To128( sigZ, sigZ );
- rem = softfloat_sub128( sigA, 0, term.v64, term.v0 );
- while ( UINT64_C( 0x8000000000000000 ) <= rem.v64 ) {
- --sigZ;
- rem =
- softfloat_add128(
- rem.v64, rem.v0, sigZ>>63, (uint64_t) ( sigZ<<1 ) );
- }
- sigZ |= ( ( rem.v64 | rem.v0 ) != 0 );
- }
- return softfloat_roundPackToF64( 0, expZ, sigZ );
- invalid:
- softfloat_raiseFlags( softfloat_flag_invalid );
- uiZ = defaultNaNF64UI;
- uiZ:
- uZ.ui = uiZ;
- return uZ.f;
-
-}
-
+/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3e, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2017 The Regents of the University of +California. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions, and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright notice, + this list of conditions, and the following disclaimer in the documentation + and/or other materials provided with the distribution. + + 3. Neither the name of the University nor the names of its contributors may + be used to endorse or promote products derived from this software without + specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY +EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE +DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +=============================================================================*/ + +#include <stdbool.h> +#include <stdint.h> +#include "platform.h" +#include "internals.h" +#include "specialize.h" +#include "softfloat.h" + +float64_t f64_sqrt( float64_t a ) +{ + union ui64_f64 uA; + uint_fast64_t uiA; + bool signA; + int_fast16_t expA; + uint_fast64_t sigA, uiZ; + struct exp16_sig64 normExpSig; + int_fast16_t expZ; + uint32_t sig32A, recipSqrt32, sig32Z; + uint_fast64_t rem; + uint32_t q; + uint_fast64_t sigZ, shiftedSigZ; + union ui64_f64 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uA.f = a; + uiA = uA.ui; + signA = signF64UI( uiA ); + expA = expF64UI( uiA ); + sigA = fracF64UI( uiA ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( expA == 0x7FF ) { + if ( sigA ) { + uiZ = softfloat_propagateNaNF64UI( uiA, 0 ); + goto uiZ; + } + if ( ! signA ) return a; + goto invalid; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( signA ) { + if ( ! (expA | sigA) ) return a; + goto invalid; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( ! expA ) { + if ( ! sigA ) return a; + normExpSig = softfloat_normSubnormalF64Sig( sigA ); + expA = normExpSig.exp; + sigA = normExpSig.sig; + } + /*------------------------------------------------------------------------ + | (`sig32Z' is guaranteed to be a lower bound on the square root of + | `sig32A', which makes `sig32Z' also a lower bound on the square root of + | `sigA'.) + *------------------------------------------------------------------------*/ + expZ = ((expA - 0x3FF)>>1) + 0x3FE; + expA &= 1; + sigA |= UINT64_C( 0x0010000000000000 ); + sig32A = sigA>>21; + recipSqrt32 = softfloat_approxRecipSqrt32_1( expA, sig32A ); + sig32Z = ((uint_fast64_t) sig32A * recipSqrt32)>>32; + if ( expA ) { + sigA <<= 8; + sig32Z >>= 1; + } else { + sigA <<= 9; + } + rem = sigA - (uint_fast64_t) sig32Z * sig32Z; + q = ((uint32_t) (rem>>2) * (uint_fast64_t) recipSqrt32)>>32; + sigZ = ((uint_fast64_t) sig32Z<<32 | 1<<5) + ((uint_fast64_t) q<<3); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( (sigZ & 0x1FF) < 0x22 ) { + sigZ &= ~(uint_fast64_t) 0x3F; + shiftedSigZ = sigZ>>6; + rem = (sigA<<52) - shiftedSigZ * shiftedSigZ; + if ( rem & UINT64_C( 0x8000000000000000 ) ) { + --sigZ; + } else { + if ( rem ) sigZ |= 1; + } + } + return softfloat_roundPackToF64( 0, expZ, sigZ ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + invalid: + softfloat_raiseFlags( softfloat_flag_invalid ); + uiZ = defaultNaNF64UI; + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |