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authorJohn Hauser <jhauser@eecs.berkeley.edu>2014-11-28 19:49:28 -0800
committerJohn Hauser <jhauser@eecs.berkeley.edu>2014-11-28 19:49:28 -0800
commit8f59d925353145a65c09301dea6c47da1f1311b1 (patch)
treec55a81490cc411be6c812a5bfcc8fdc48296def9 /source/f32_div.c
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First draft of RC for Release 3, to start review process.
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diff --git a/source/f32_div.c b/source/f32_div.c
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+
+/*============================================================================
+
+This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
+Package, Release 3, by John R. Hauser.
+
+Copyright 2011, 2012, 2013, 2014 The Regents of the University of California
+(Regents). All Rights Reserved. Redistribution and use in source and binary
+forms, with or without modification, are permitted provided that the following
+conditions are met:
+
+Redistributions of source code must retain the above copyright notice,
+this list of conditions, and the following two paragraphs of disclaimer.
+Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions, and the following two paragraphs of disclaimer in the
+documentation and/or other materials provided with the distribution. Neither
+the name of the Regents nor the names of its contributors may be used to
+endorse or promote products derived from this software without specific prior
+written permission.
+
+IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
+OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
+BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
+HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
+MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+
+=============================================================================*/
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "platform.h"
+#include "internals.h"
+#include "specialize.h"
+#include "softfloat.h"
+
+float32_t f32_div( float32_t a, float32_t b )
+{
+ union ui32_f32 uA;
+ uint_fast32_t uiA;
+ bool signA;
+ int_fast16_t expA;
+ uint_fast32_t sigA;
+ union ui32_f32 uB;
+ uint_fast32_t uiB;
+ bool signB;
+ int_fast16_t expB;
+ uint_fast32_t sigB;
+ bool signZ;
+ struct exp16_sig32 normExpSig;
+ int_fast16_t expZ;
+#ifdef SOFTFLOAT_FAST_DIV64TO32
+ uint_fast64_t sig64A;
+ uint_fast32_t sigZ;
+#else
+ uint_fast32_t sigZ;
+ uint_fast64_t rem;
+#endif
+ uint_fast32_t uiZ;
+ union ui32_f32 uZ;
+
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ uA.f = a;
+ uiA = uA.ui;
+ signA = signF32UI( uiA );
+ expA = expF32UI( uiA );
+ sigA = fracF32UI( uiA );
+ uB.f = b;
+ uiB = uB.ui;
+ signB = signF32UI( uiB );
+ expB = expF32UI( uiB );
+ sigB = fracF32UI( uiB );
+ signZ = signA ^ signB;
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( expA == 0xFF ) {
+ if ( sigA ) goto propagateNaN;
+ if ( expB == 0xFF ) {
+ if ( sigB ) goto propagateNaN;
+ goto invalid;
+ }
+ goto infinity;
+ }
+ if ( expB == 0xFF ) {
+ if ( sigB ) goto propagateNaN;
+ goto zero;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( ! expB ) {
+ if ( ! sigB ) {
+ if ( ! (expA | sigA) ) goto invalid;
+ softfloat_raiseFlags( softfloat_flag_infinite );
+ goto infinity;
+ }
+ normExpSig = softfloat_normSubnormalF32Sig( sigB );
+ expB = normExpSig.exp;
+ sigB = normExpSig.sig;
+ }
+ if ( ! expA ) {
+ if ( ! sigA ) goto zero;
+ normExpSig = softfloat_normSubnormalF32Sig( sigA );
+ expA = normExpSig.exp;
+ sigA = normExpSig.sig;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ expZ = expA - expB + 0x7E;
+ sigA |= 0x00800000;
+ sigB |= 0x00800000;
+#ifdef SOFTFLOAT_FAST_DIV64TO32
+ if ( sigA < sigB ) {
+ --expZ;
+ sig64A = (uint_fast64_t) sigA<<31;
+ } else {
+ sig64A = (uint_fast64_t) sigA<<30;
+ }
+ sigZ = sig64A / sigB;
+ if ( ! (sigZ & 0x3F) ) sigZ |= ((uint_fast64_t) sigB * sigZ != sig64A);
+#else
+ if ( sigA < sigB ) {
+ --expZ;
+ sigA <<= 8;
+ } else {
+ sigA <<= 7;
+ }
+ sigB <<= 8;
+ sigZ = ((uint_fast64_t) sigA * softfloat_approxRecip32_1( sigB ))>>32;
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ sigZ += 2;
+ if ( (sigZ & 0x3F) < 2 ) {
+ sigZ &= ~3;
+#ifdef SOFTFLOAT_FAST_INT64
+ rem = ((uint_fast64_t) sigA<<31) - (uint_fast64_t) sigZ * sigB;
+#else
+ rem = ((uint_fast64_t) sigA<<32) - (uint_fast64_t) (sigZ<<1) * sigB;
+#endif
+ if ( rem & UINT64_C( 0x8000000000000000 ) ) {
+ sigZ -= 4;
+ } else {
+ if ( rem ) sigZ |= 1;
+ }
+ }
+#endif
+ return softfloat_roundPackToF32( signZ, expZ, sigZ );
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ propagateNaN:
+ uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
+ goto uiZ;
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ invalid:
+ softfloat_raiseFlags( softfloat_flag_invalid );
+ uiZ = defaultNaNF32UI;
+ goto uiZ;
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ infinity:
+ uiZ = packToF32UI( signZ, 0xFF, 0 );
+ goto uiZ;
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ zero:
+ uiZ = packToF32UI( signZ, 0, 0 );
+ uiZ:
+ uZ.ui = uiZ;
+ return uZ.f;
+
+}
+
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