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/******************************************************************************
* Copyright (c) 2011-2014, Peter Collingbourne <peter@pcc.me.uk>
* Copyright (c) 2011-2014, Texas Instruments Incorporated - http://www.ti.com/
* 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 disclaimer.
* * 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.
* * Neither the name of Texas Instruments Incorporated 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 "cpu.h"
//FOIL-based long mul_hi
//
// Summary: Treat mul_hi(long x, long y) as:
// (a+b) * (c+d) where a and c are the high-order parts of x and y respectively
// and b and d are the low-order parts of x and y.
// Thinking back to algebra, we use FOIL to do the work.
_CLC_OVERLOAD _CLC_DEF long mul_hi(long x, long y){
long f, o, i;
ulong l;
//Move the high/low halves of x/y into the lower 32-bits of variables so
//that we can multiply them without worrying about overflow.
long x_hi = x >> 32;
long x_lo = x & UINT_MAX;
long y_hi = y >> 32;
long y_lo = y & UINT_MAX;
//Multiply all of the components according to FOIL method
f = x_hi * y_hi;
o = x_hi * y_lo;
i = x_lo * y_hi;
l = x_lo * y_lo;
//Now add the components back together in the following steps:
//F: doesn't need to be modified
//O/I: Need to be added together.
//L: Shift right by 32-bits, then add into the sum of O and I
//Once O/I/L are summed up, then shift the sum by 32-bits and add to F.
//
//We use hadd to give us a bit of extra precision for the intermediate sums
//but as a result, we shift by 31 bits instead of 32
return (long)(f + (hadd(o, (i + (long)((ulong)l>>32))) >> 31));
}
_CLC_OVERLOAD _CLC_DEF ulong mul_hi(ulong x, ulong y)
{
ulong f, o, i;
ulong l;
//Move the high/low halves of x/y into the lower 32-bits of variables so
//that we can multiply them without worrying about overflow.
ulong x_hi = x >> 32;
ulong x_lo = x & UINT_MAX;
ulong y_hi = y >> 32;
ulong y_lo = y & UINT_MAX;
//Multiply all of the components according to FOIL method
f = x_hi * y_hi;
o = x_hi * y_lo;
i = x_lo * y_hi;
l = x_lo * y_lo;
//Now add the components back together, taking care to respect the fact that:
//F: doesn't need to be modified
//O/I: Need to be added together.
//L: Shift right by 32-bits, then add into the sum of O and I
//Once O/I/L are summed up, then shift the sum by 32-bits and add to F.
//
//We use hadd to give us a bit of extra precision for the intermediate sums
//but as a result, we shift by 31 bits instead of 32
return (f + (hadd(o, (i + (l>>32))) >> 31));
}
BINARY_VEC_DEF(char, char, mul_hi, mul_hi)
BINARY_VEC_DEF(uchar, uchar, mul_hi, mul_hi)
BINARY_VEC_DEF(short, short, mul_hi, mul_hi)
BINARY_VEC_DEF(ushort, ushort,mul_hi, mul_hi)
BINARY_VEC_DEF(int, int, mul_hi, mul_hi)
BINARY_VEC_DEF(uint, uint, mul_hi, mul_hi)
BINARY_VEC_DEF(long, long, mul_hi, mul_hi)
BINARY_VEC_DEF(ulong, ulong, mul_hi, mul_hi)
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