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Diffstat (limited to 'src/builtins/mul_hi.cl')
| -rw-r--r-- | src/builtins/mul_hi.cl | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/builtins/mul_hi.cl b/src/builtins/mul_hi.cl new file mode 100644 index 0000000..5b3368e --- /dev/null +++ b/src/builtins/mul_hi.cl @@ -0,0 +1,102 @@ +/****************************************************************************** + * 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) |