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
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*
* Copyright (c) 2001-2005 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.
*/
#ifndef __BASE__CHUNK_GENERATOR_HH__
#define __BASE__CHUNK_GENERATOR_HH__
/**
* @file
* Declaration and inline definition of ChunkGenerator object.
*/
#include <algorithm>
#include "base/intmath.hh"
#include "targetarch/isa_traits.hh" // for Addr
/**
* This class takes an arbitrary memory region (address/length pair)
* and generates a series of appropriately (e.g. block- or page-)
* aligned chunks covering the same region.
*
* Example usage:
\code
for (ChunkGenerator gen(addr, size, chunkSize); !gen.done(); gen.next()) {
doSomethingChunky(gen.addr(), gen.size());
}
\endcode
*/
class ChunkGenerator
{
private:
/** The starting address of the current chunk. */
Addr curAddr;
/** The starting address of the next chunk (after the current one). */
Addr nextAddr;
/** The size of the current chunk (in bytes). */
int curSize;
/** The number of bytes remaining in the region after the current chunk. */
int sizeLeft;
/** The maximum chunk size, e.g., the cache block size or page size. */
const int chunkSize;
public:
/**
* Constructor.
* @param startAddr The starting address of the region.
* @param totalSize The total size of the region.
* @param _chunkSize The size/alignment of chunks into which
* the region should be decomposed.
*/
ChunkGenerator(Addr startAddr, int totalSize, int _chunkSize)
: chunkSize(_chunkSize)
{
// chunkSize must be a power of two
assert(chunkSize == 0 || isPowerOf2(chunkSize));
// set up initial chunk.
curAddr = startAddr;
if (chunkSize == 0) //Special Case, if we see 0, assume no chuncking
{
nextAddr = startAddr + totalSize;
}
else
{
// nextAddr should be *next* chunk start
nextAddr = roundUp(startAddr, chunkSize);
if (curAddr == nextAddr) {
// ... even if startAddr is already chunk-aligned
nextAddr += chunkSize;
}
}
// how many bytes are left between curAddr and the end of this chunk?
int left_in_chunk = nextAddr - curAddr;
curSize = std::min(totalSize, left_in_chunk);
sizeLeft = totalSize - curSize;
}
/** Return starting address of current chunk. */
Addr addr() { return curAddr; }
/** Return size in bytes of current chunk. */
int size() { return curSize; }
/**
* Are we done? That is, did the last call to next() advance
* past the end of the region?
* @return True if yes, false if more to go.
*/
bool done() { return (curSize == 0); }
/**
* Advance generator to next chunk.
* @return True if successful, false if unsuccessful
* (because we were at the last chunk).
*/
bool next()
{
if (sizeLeft == 0) {
curSize = 0;
return false;
}
curAddr = nextAddr;
curSize = std::min(sizeLeft, chunkSize);
sizeLeft -= curSize;
nextAddr += curSize;
return true;
}
};
#endif // __BASE__CHUNK_GENERATOR_HH__
|
