diff options
Diffstat (limited to 'src/libs/softfloat-3e/source/f128_sqrt.c')
-rw-r--r-- | src/libs/softfloat-3e/source/f128_sqrt.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/libs/softfloat-3e/source/f128_sqrt.c b/src/libs/softfloat-3e/source/f128_sqrt.c new file mode 100644 index 00000000..1a1539b0 --- /dev/null +++ b/src/libs/softfloat-3e/source/f128_sqrt.c @@ -0,0 +1,201 @@ + +/*============================================================================ + +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, 2015, 2016, 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" + +float128_t f128_sqrt( float128_t a SOFTFLOAT_STATE_DECL_COMMA ) +{ + union ui128_f128 uA; + uint_fast64_t uiA64, uiA0; + bool signA; + int_fast32_t expA; + struct uint128 sigA, uiZ; + struct exp32_sig128 normExpSig; + int_fast32_t expZ; + uint_fast32_t sig32A, recipSqrt32, sig32Z; + struct uint128 rem; + uint32_t qs[3]; + uint_fast32_t q; + uint_fast64_t x64, sig64Z; + struct uint128 y, term; + uint_fast64_t sigZExtra; + struct uint128 sigZ; + union ui128_f128 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uA.f = a; + uiA64 = uA.ui.v64; + uiA0 = uA.ui.v0; + signA = signF128UI64( uiA64 ); + expA = expF128UI64( uiA64 ); + sigA.v64 = fracF128UI64( uiA64 ); + sigA.v0 = uiA0; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( expA == 0x7FFF ) { + if ( sigA.v64 | sigA.v0 ) { + uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, 0, 0 SOFTFLOAT_STATE_ARG_COMMA ); + goto uiZ; + } + if ( ! signA ) return a; + goto invalid; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( signA ) { + if ( ! (expA | sigA.v64 | sigA.v0) ) return a; + goto invalid; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( ! expA ) { + if ( ! (sigA.v64 | sigA.v0) ) return a; + normExpSig = softfloat_normSubnormalF128Sig( sigA.v64, sigA.v0 ); + 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 - 0x3FFF)>>1) + 0x3FFE; + expA &= 1; + sigA.v64 |= UINT64_C( 0x0001000000000000 ); + sig32A = sigA.v64>>17; + recipSqrt32 = softfloat_approxRecipSqrt32_1( expA, sig32A ); + sig32Z = ((uint_fast64_t) sig32A * recipSqrt32)>>32; + if ( expA ) { + sig32Z >>= 1; + rem = softfloat_shortShiftLeft128( sigA.v64, sigA.v0, 12 ); + } else { + rem = softfloat_shortShiftLeft128( sigA.v64, sigA.v0, 13 ); + } + qs[2] = sig32Z; + rem.v64 -= (uint_fast64_t) sig32Z * sig32Z; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + q = ((uint32_t) (rem.v64>>2) * (uint_fast64_t) recipSqrt32)>>32; + x64 = (uint_fast64_t) sig32Z<<32; + sig64Z = x64 + ((uint_fast64_t) q<<3); + y = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 ); + /*------------------------------------------------------------------------ + | (Repeating this loop is a rare occurrence.) + *------------------------------------------------------------------------*/ + for (;;) { + term = softfloat_mul64ByShifted32To128( x64 + sig64Z, q ); + rem = softfloat_sub128( y.v64, y.v0, term.v64, term.v0 ); + if ( ! (rem.v64 & UINT64_C( 0x8000000000000000 )) ) break; + --q; + sig64Z -= 1<<3; + } + qs[1] = q; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + q = ((rem.v64>>2) * recipSqrt32)>>32; + y = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 ); + sig64Z <<= 1; + /*------------------------------------------------------------------------ + | (Repeating this loop is a rare occurrence.) + *------------------------------------------------------------------------*/ + for (;;) { + term = softfloat_shortShiftLeft128( 0, sig64Z, 32 ); + term = softfloat_add128( term.v64, term.v0, 0, (uint_fast64_t) q<<6 ); + term = softfloat_mul128By32( term.v64, term.v0, q ); + rem = softfloat_sub128( y.v64, y.v0, term.v64, term.v0 ); + if ( ! (rem.v64 & UINT64_C( 0x8000000000000000 )) ) break; + --q; + } + qs[0] = q; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + q = (((rem.v64>>2) * recipSqrt32)>>32) + 2; + sigZExtra = (uint64_t) ((uint_fast64_t) q<<59); + term = softfloat_shortShiftLeft128( 0, qs[1], 53 ); + sigZ = + softfloat_add128( + (uint_fast64_t) qs[2]<<18, ((uint_fast64_t) qs[0]<<24) + (q>>5), + term.v64, term.v0 + ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( (q & 0xF) <= 2 ) { + q &= ~3; + sigZExtra = (uint64_t) ((uint_fast64_t) q<<59); + y = softfloat_shortShiftLeft128( sigZ.v64, sigZ.v0, 6 ); + y.v0 |= sigZExtra>>58; + term = softfloat_sub128( y.v64, y.v0, 0, q ); + y = softfloat_mul64ByShifted32To128( term.v0, q ); + term = softfloat_mul64ByShifted32To128( term.v64, q ); + term = softfloat_add128( term.v64, term.v0, 0, y.v64 ); + rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 20 ); + term = softfloat_sub128( term.v64, term.v0, rem.v64, rem.v0 ); + /*-------------------------------------------------------------------- + | The concatenation of `term' and `y.v0' is now the negative remainder + | (3 words altogether). + *--------------------------------------------------------------------*/ + if ( term.v64 & UINT64_C( 0x8000000000000000 ) ) { + sigZExtra |= 1; + } else { + if ( term.v64 | term.v0 | y.v0 ) { + if ( sigZExtra ) { + --sigZExtra; + } else { + sigZ = softfloat_sub128( sigZ.v64, sigZ.v0, 0, 1 ); + sigZExtra = ~0; + } + } + } + } + return softfloat_roundPackToF128( 0, expZ, sigZ.v64, sigZ.v0, sigZExtra SOFTFLOAT_STATE_ARG_COMMA ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + invalid: + softfloat_raiseFlags( softfloat_flag_invalid SOFTFLOAT_STATE_ARG_COMMA ); + uiZ.v64 = defaultNaNF128UI64; + uiZ.v0 = defaultNaNF128UI0; + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |