1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Gabe Black
29 */
30
31#ifndef __BASE_CONDCODE_HH__
32#define __BASE_CONDCODE_HH__
33
34#include "base/bitfield.hh"
35#include "base/trace.hh"
36
37/**
38 * Calculate the carry flag from an addition. This should work even when
39 * a carry value is also added in.
40 */
41inline
42bool
43findCarry(int width, uint64_t dest, uint64_t src1, uint64_t src2) {
44    int shift = width - 1;
45    return ((~(dest >> shift) & 1) +
46            ((src1 >> shift) & 1) +
47            ((src2 >> shift) & 1)) & 0x2;
48}
49
50/**
51 * Calculate the overflow flag from an addition.
52 */
53inline
54bool
55findOverflow(int width, uint64_t dest, uint64_t src1, uint64_t src2) {
56    int shift = width - 1;
57    return ((src1 ^ ~src2) & (src1 ^ dest)) & (1ULL << shift);
58}
59
60/**
61 * Calculate the parity of a value. 1 is for odd parity and 0 is for even.
62 */
63inline
64bool
65findParity(int width, uint64_t dest) {
66    dest &= mask(width);
67    dest ^= (dest >> 32);
68    dest ^= (dest >> 16);
69    dest ^= (dest >> 8);
70    dest ^= (dest >> 4);
71    dest ^= (dest >> 2);
72    dest ^= (dest >> 1);
73    return dest & 1;
74}
75
76/**
77 * Calculate the negative flag.
78 */
79inline
80bool
81findNegative(int width, uint64_t dest) {
82    return bits(dest, width - 1, width - 1);
83}
84
85/**
86 * Calculate the zero flag.
87 */
88inline
89bool
90findZero(int width, uint64_t dest) {
91    return !(dest & mask(width));
92}
93
94#endif // __BASE_CONDCODE_HH__
95