1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
/*
* 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"
#include "base/trace.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) & 1) +
((src1 >> shift) & 1) +
((src2 >> shift) & 1)) & 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__
|
