-\r
-#include <stdbool.h>\r
-#include <stdint.h>\r
-#include "platform.h"\r
-#include "primitives.h"\r
-#include "internals.h"\r
-#include "specialize.h"\r
-#include "softfloat.h"\r
-\r
-float64_t f64_sqrt( float64_t a )\r
-{\r
- union ui64_f64 uA;\r
- uint_fast64_t uiA;\r
- bool signA;\r
- int_fast16_t expA;\r
- uint_fast64_t sigA, uiZ;\r
- struct exp16_sig64 normExpSig;\r
- int_fast16_t expZ;\r
- uint_fast32_t sigZ32;\r
- uint_fast64_t sigZ;\r
- struct uint128 term, rem;\r
- union ui64_f64 uZ;\r
-\r
- uA.f = a;\r
- uiA = uA.ui;\r
- signA = signF64UI( uiA );\r
- expA = expF64UI( uiA );\r
- sigA = fracF64UI( uiA );\r
- if ( expA == 0x7FF ) {\r
- if ( sigA ) {\r
- uiZ = softfloat_propagateNaNF64UI( uiA, 0 );\r
- goto uiZ;\r
- }\r
- if ( ! signA ) return a;\r
- goto invalid;\r
- }\r
- if ( signA ) {\r
- if ( ! ( expA | sigA ) ) return a;\r
- goto invalid;\r
- }\r
- if ( ! expA ) {\r
- if ( ! sigA ) return a;\r
- normExpSig = softfloat_normSubnormalF64Sig( sigA );\r
- expA = normExpSig.exp;\r
- sigA = normExpSig.sig;\r
- }\r
- expZ = ( ( expA - 0x3FF )>>1 ) + 0x3FE;\r
- sigA |= UINT64_C( 0x0010000000000000 );\r
- sigZ32 = softfloat_estimateSqrt32( expA, sigA>>21 );\r
- sigA <<= 9 - ( expA & 1 );\r
- sigZ =\r
- softfloat_estimateDiv128To64( sigA, 0, (uint_fast64_t) sigZ32<<32 )\r
- + ( (uint_fast64_t) sigZ32<<30 );\r
- if ( ( sigZ & 0x1FF ) <= 5 ) {\r
- term = softfloat_mul64To128( sigZ, sigZ );\r
- rem = softfloat_sub128( sigA, 0, term.v64, term.v0 );\r
- while ( UINT64_C( 0x8000000000000000 ) <= rem.v64 ) {\r
- --sigZ;\r
- rem =\r
- softfloat_add128(\r
- rem.v64, rem.v0, sigZ>>63, (uint64_t) ( sigZ<<1 ) );\r
- }\r
- sigZ |= ( ( rem.v64 | rem.v0 ) != 0 );\r
- }\r
- return softfloat_roundPackToF64( 0, expZ, sigZ );\r
- invalid:\r
- softfloat_raiseFlags( softfloat_flag_invalid );\r
- uiZ = defaultNaNF64UI;\r
- uiZ:\r
- uZ.ui = uiZ;\r
- return uZ.f;\r
-\r
-}\r
-\r
+
+/*============================================================================
+
+This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
+Package, Release 3d, 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;
+
+}
+
projects / riscv-isa-sim.git / blobdiff