--- /dev/null
+
+/*============================================================================
+
+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, 2015, 2016 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"
+
+float16_t f16_rem( float16_t a, float16_t b )
+{
+ union ui16_f16 uA;
+ uint_fast16_t uiA;
+ bool signA;
+ int_fast8_t expA;
+ uint_fast16_t sigA;
+ union ui16_f16 uB;
+ uint_fast16_t uiB;
+ int_fast8_t expB;
+ uint_fast16_t sigB;
+ struct exp8_sig16 normExpSig;
+ uint16_t rem;
+ int_fast8_t expDiff;
+ uint_fast16_t q;
+ uint32_t recip32, q32;
+ uint16_t altRem, meanRem;
+ bool signRem;
+ uint_fast16_t uiZ;
+ union ui16_f16 uZ;
+
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ uA.f = a;
+ uiA = uA.ui;
+ signA = signF16UI( uiA );
+ expA = expF16UI( uiA );
+ sigA = fracF16UI( uiA );
+ uB.f = b;
+ uiB = uB.ui;
+ expB = expF16UI( uiB );
+ sigB = fracF16UI( uiB );
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( expA == 0x1F ) {
+ if ( sigA || ((expB == 0x1F) && sigB) ) goto propagateNaN;
+ goto invalid;
+ }
+ if ( expB == 0x1F ) {
+ if ( sigB ) goto propagateNaN;
+ return a;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( ! expB ) {
+ if ( ! sigB ) goto invalid;
+ normExpSig = softfloat_normSubnormalF16Sig( sigB );
+ expB = normExpSig.exp;
+ sigB = normExpSig.sig;
+ }
+ if ( ! expA ) {
+ if ( ! sigA ) return a;
+ normExpSig = softfloat_normSubnormalF16Sig( sigA );
+ expA = normExpSig.exp;
+ sigA = normExpSig.sig;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ rem = sigA | 0x0400;
+ sigB |= 0x0400;
+ expDiff = expA - expB;
+ if ( expDiff < 1 ) {
+ if ( expDiff < -1 ) return a;
+ sigB <<= 3;
+ if ( expDiff ) {
+ rem <<= 2;
+ q = 0;
+ } else {
+ rem <<= 3;
+ q = (sigB <= rem);
+ if ( q ) rem -= sigB;
+ }
+ } else {
+ recip32 = softfloat_approxRecip32_1( (uint_fast32_t) sigB<<21 );
+ /*--------------------------------------------------------------------
+ | Changing the shift of `rem' here requires also changing the initial
+ | subtraction from `expDiff'.
+ *--------------------------------------------------------------------*/
+ rem <<= 4;
+ expDiff -= 31;
+ /*--------------------------------------------------------------------
+ | The scale of `sigB' affects how many bits are obtained during each
+ | cycle of the loop. Currently this is 29 bits per loop iteration,
+ | which is believed to be the maximum possible.
+ *--------------------------------------------------------------------*/
+ sigB <<= 3;
+ for (;;) {
+ q32 = (rem * (uint_fast64_t) recip32)>>16;
+ if ( expDiff < 0 ) break;
+ rem = -((uint_fast16_t) q32 * sigB);
+ expDiff -= 29;
+ }
+ /*--------------------------------------------------------------------
+ | (`expDiff' cannot be less than -30 here.)
+ *--------------------------------------------------------------------*/
+ q32 >>= ~expDiff & 31;
+ q = q32;
+ rem = (rem<<(expDiff + 30)) - q * sigB;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ do {
+ altRem = rem;
+ ++q;
+ rem -= sigB;
+ } while ( ! (rem & 0x8000) );
+ meanRem = rem + altRem;
+ if ( (meanRem & 0x8000) || (! meanRem && (q & 1)) ) rem = altRem;
+ signRem = signA;
+ if ( 0x8000 <= rem ) {
+ signRem = ! signRem;
+ rem = -rem;
+ }
+ return softfloat_normRoundPackToF16( signRem, expB, rem );
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ propagateNaN:
+ uiZ = softfloat_propagateNaNF16UI( uiA, uiB );
+ goto uiZ;
+ invalid:
+ softfloat_raiseFlags( softfloat_flag_invalid );
+ uiZ = defaultNaNF16UI;
+ uiZ:
+ uZ.ui = uiZ;
+ return uZ.f;
+
+}
+
projects / riscv-isa-sim.git / blobdiff