94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
/*
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* Copyright (c) 2003-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Gabe Black
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*/
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#ifndef __BASE_CONDCODE_HH__
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#define __BASE_CONDCODE_HH__
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#include "base/bitfield.hh"
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#include "base/trace.hh"
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/**
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* Calculate the carry flag from an addition. This should work even when
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* a carry value is also added in.
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*/
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inline
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bool
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findCarry(int width, uint64_t dest, uint64_t src1, uint64_t src2) {
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int shift = width - 1;
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return ((~(dest >> shift) & 1) +
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((src1 >> shift) & 1) +
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((src2 >> shift) & 1)) & 0x2;
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}
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/**
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* Calculate the overflow flag from an addition.
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*/
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inline
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bool
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findOverflow(int width, uint64_t dest, uint64_t src1, uint64_t src2) {
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int shift = width - 1;
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return ((src1 ^ ~src2) & (src1 ^ dest)) & (1ULL << shift);
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}
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/**
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* Calculate the parity of a value. 1 is for odd parity and 0 is for even.
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*/
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inline
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bool
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findParity(int width, uint64_t dest) {
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dest &= mask(width);
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dest ^= (dest >> 32);
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dest ^= (dest >> 16);
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dest ^= (dest >> 8);
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dest ^= (dest >> 4);
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dest ^= (dest >> 2);
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dest ^= (dest >> 1);
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return dest & 1;
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}
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/**
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* Calculate the negative flag.
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*/
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inline
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bool
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findNegative(int width, uint64_t dest) {
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return bits(dest, width - 1, width - 1);
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}
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/**
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* Calculate the zero flag.
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*/
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inline
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bool
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findZero(int width, uint64_t dest) {
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return !(dest & mask(width));
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}
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#endif // __BASE_CONDCODE_HH__
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