diff options
Diffstat (limited to 'softfloat/f32_div.c')
-rw-r--r--[-rwxr-xr-x] | softfloat/f32_div.c | 114 |
1 files changed, 98 insertions, 16 deletions
diff --git a/softfloat/f32_div.c b/softfloat/f32_div.c index 3bbc126..8d44479 100755..100644 --- a/softfloat/f32_div.c +++ b/softfloat/f32_div.c @@ -1,5 +1,38 @@ -// See LICENSE.SoftFloat for license details. +/*============================================================================ + +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 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> @@ -23,21 +56,31 @@ float32_t f32_div( float32_t a, float32_t b ) 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 ); + expA = expF32UI( uiA ); + sigA = fracF32UI( uiA ); uB.f = b; uiB = uB.ui; signB = signF32UI( uiB ); - expB = expF32UI( uiB ); - sigB = fracF32UI( uiB ); + expB = expF32UI( uiB ); + sigB = fracF32UI( uiB ); signZ = signA ^ signB; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ if ( expA == 0xFF ) { if ( sigA ) goto propagateNaN; if ( expB == 0xFF ) { @@ -50,10 +93,12 @@ float32_t f32_div( float32_t a, float32_t b ) if ( sigB ) goto propagateNaN; goto zero; } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ if ( ! expB ) { if ( ! sigB ) { - if ( ! ( expA | sigA ) ) goto invalid; - softfloat_raiseFlags( softfloat_flag_infinity ); + if ( ! (expA | sigA) ) goto invalid; + softfloat_raiseFlags( softfloat_flag_infinite ); goto infinity; } normExpSig = softfloat_normSubnormalF32Sig( sigB ); @@ -66,28 +111,65 @@ float32_t f32_div( float32_t a, float32_t b ) expA = normExpSig.exp; sigA = normExpSig.sig; } - expZ = expA - expB + 0x7D; - sigA = ( sigA | 0x00800000 )<<7; - sigB = ( sigB | 0x00800000 )<<8; - if ( sigB <= ( sigA + sigA ) ) { - ++expZ; - sigA >>= 1; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + 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 = ( (uint_fast64_t) sigA<<32 ) / sigB; - if ( ! ( sigZ & 0x3F ) ) { - sigZ |= ( (uint_fast64_t) sigB * sigZ != (uint_fast64_t) sigA<<32 ); + 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: |