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
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28 * Authors: Steve Reinhardt
31 #ifndef __BASE__CHUNK_GENERATOR_HH__
32 #define __BASE__CHUNK_GENERATOR_HH__
36 * Declaration and inline definition of ChunkGenerator object.
41 #include "base/intmath.hh"
42 #include "base/types.hh"
45 * This class takes an arbitrary memory region (address/length pair)
46 * and generates a series of appropriately (e.g. block- or page-)
47 * aligned chunks covering the same region.
52 for (ChunkGenerator gen(addr, size, chunkSize); !gen.done(); gen.next()) {
53 doSomethingChunky(gen.addr(), gen.size());
60 /** The starting address of the current chunk. */
62 /** The starting address of the next chunk (after the current one). */
64 /** The size of the current chunk (in bytes). */
66 /** The number of bytes remaining in the region after the current chunk. */
68 /** The start address so we can calculate offset in writing block. */
70 /** The maximum chunk size, e.g., the cache block size or page size. */
71 const unsigned chunkSize;
76 * @param _startAddr The starting address of the region.
77 * @param totalSize The total size of the region.
78 * @param _chunkSize The size/alignment of chunks into which
79 * the region should be decomposed.
81 ChunkGenerator(Addr _startAddr, unsigned totalSize, unsigned _chunkSize)
82 : startAddr(_startAddr), chunkSize(_chunkSize)
84 // chunkSize must be a power of two
85 assert(chunkSize == 0 || isPowerOf2(chunkSize));
86 assert(totalSize >= 0);
88 // set up initial chunk.
91 if (chunkSize == 0) //Special Case, if we see 0, assume no chuncking
93 nextAddr = startAddr + totalSize;
97 // nextAddr should be *next* chunk start
98 nextAddr = roundUp(startAddr, chunkSize);
99 if (curAddr == nextAddr) {
100 // ... even if startAddr is already chunk-aligned
101 nextAddr += chunkSize;
105 // how many bytes are left between curAddr and the end of this chunk?
106 unsigned left_in_chunk = nextAddr - curAddr;
107 curSize = std::min(totalSize, left_in_chunk);
108 sizeLeft = totalSize - curSize;
111 /** Return starting address of current chunk. */
112 Addr addr() const { return curAddr; }
113 /** Return size in bytes of current chunk. */
114 unsigned size() const { return curSize; }
116 /** Number of bytes we have already chunked up. */
117 unsigned complete() const { return curAddr - startAddr; }
120 * Are we done? That is, did the last call to next() advance
121 * past the end of the region?
122 * @return True if yes, false if more to go.
124 bool done() const { return (curSize == 0); }
127 * Advance generator to next chunk.
128 * @return True if successful, false if unsuccessful
129 * (because we were at the last chunk).
140 curSize = std::min(sizeLeft, chunkSize);
147 #endif // __BASE__CHUNK_GENERATOR_HH__