diff options
Diffstat (limited to 'src/base')
-rw-r--r-- | src/base/condcodes.hh | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/base/condcodes.hh b/src/base/condcodes.hh new file mode 100644 index 000000000..10109e4ad --- /dev/null +++ b/src/base/condcodes.hh @@ -0,0 +1,91 @@ +/* + * Copyright (c) 2003-2005 The Regents of The University of Michigan + * 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 the copyright holders 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. + * + * Authors: Gabe Black + */ + +#ifndef __BASE_CONDCODE_HH__ +#define __BASE_CONDCODE_HH__ + +#include "base/bitfield.hh" + +/** + * Calculate the carry flag from an addition. This should work even when + * a carry value is also added in. + */ +inline +bool +findCarry(int width, uint64_t dest, uint64_t src1, uint64_t src2) { + int shift = width - 1; + return (~(dest >> shift) + (src1 >> shift) + (src2 >> shift)) & 0x2; +} + +/** + * Calculate the overflow flag from an addition. + */ +inline +bool +findOverflow(int width, uint64_t dest, uint64_t src1, uint64_t src2) { + int shift = width - 1; + return ((src1 ^ ~src2) & (src1 ^ dest)) & (1 << shift); +} + +/** + * Calculate the parity of a value. 1 is for odd parity and 0 is for even. + */ +inline +bool +findParity(int width, uint64_t dest) { + dest &= width; + dest ^= (dest >> 32); + dest ^= (dest >> 16); + dest ^= (dest >> 8); + dest ^= (dest >> 4); + dest ^= (dest >> 2); + dest ^= (dest >> 1); + return dest & 1; +} + +/** + * Calculate the negative flag. + */ +inline +bool +findNegative(int width, uint64_t dest) { + return bits(dest, width - 1, width - 1); +} + +/** + * Calculate the zero flag. + */ +inline +bool +findZero(int width, uint64_t dest) { + return !(dest & mask(width)); +} + +#endif // __BASE_CONDCODE_HH__ |