2 * Copyright (c) 2001-2005 The Regents of The University of Michigan
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16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 * Authors: Steve Reinhardt
31 #ifndef __BASE__CHUNK_GENERATOR_HH__
32 #define __BASE__CHUNK_GENERATOR_HH__
36 * Declaration and inline definition of ChunkGenerator object.
40 #include "base/intmath.hh"
41 #include "arch/isa_traits.hh" // for Addr
44 * This class takes an arbitrary memory region (address/length pair)
45 * and generates a series of appropriately (e.g. block- or page-)
46 * aligned chunks covering the same region.
51 for (ChunkGenerator gen(addr, size, chunkSize); !gen.done(); gen.next()) {
52 doSomethingChunky(gen.addr(), gen.size());
59 /** The starting address of the current chunk. */
61 /** The starting address of the next chunk (after the current one). */
63 /** The size of the current chunk (in bytes). */
65 /** The number of bytes remaining in the region after the current chunk. */
67 /** The start address so we can calculate offset in writing block. */
69 /** The maximum chunk size, e.g., the cache block size or page size. */
75 * @param _startAddr The starting address of the region.
76 * @param totalSize The total size of the region.
77 * @param _chunkSize The size/alignment of chunks into which
78 * the region should be decomposed.
80 ChunkGenerator(Addr _startAddr, int totalSize, int _chunkSize)
81 : startAddr(_startAddr), chunkSize(_chunkSize)
83 // chunkSize must be a power of two
84 assert(chunkSize == 0 || isPowerOf2(chunkSize));
85 assert(totalSize >= 0);
87 // set up initial chunk.
90 if (chunkSize == 0) //Special Case, if we see 0, assume no chuncking
92 nextAddr = startAddr + totalSize;
96 // nextAddr should be *next* chunk start
97 nextAddr = roundUp(startAddr, chunkSize);
98 if (curAddr == nextAddr) {
99 // ... even if startAddr is already chunk-aligned
100 nextAddr += chunkSize;
104 // how many bytes are left between curAddr and the end of this chunk?
105 int left_in_chunk = nextAddr - curAddr;
106 curSize = std::min(totalSize, left_in_chunk);
107 sizeLeft = totalSize - curSize;
110 /** Return starting address of current chunk. */
111 Addr addr() { return curAddr; }
112 /** Return size in bytes of current chunk. */
113 int size() { return curSize; }
115 /** Number of bytes we have already chunked up. */
116 int complete() { return curAddr - startAddr; }
118 * Are we done? That is, did the last call to next() advance
119 * past the end of the region?
120 * @return True if yes, false if more to go.
122 bool done() { return (curSize == 0); }
125 * Advance generator to next chunk.
126 * @return True if successful, false if unsuccessful
127 * (because we were at the last chunk).
137 curSize = std::min(sizeLeft, chunkSize);
144 #endif // __BASE__CHUNK_GENERATOR_HH__