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authorSteve Reinhardt <stever@eecs.umich.edu>2005-12-23 14:06:27 -0500
committerSteve Reinhardt <stever@eecs.umich.edu>2005-12-23 14:06:27 -0500
commitdce0c77ca296228958d14f6a087cb563ae52997b (patch)
tree33dfc28d892d2d911251344eb65e8894272aab69 /base
parent91192dbe979b6508398ebb14b2d514833114908e (diff)
downloadgem5-dce0c77ca296228958d14f6a087cb563ae52997b.tar.xz
Add ChunkGenerator object for breaking arbitrary regions
into block- or page-sized chunks. --HG-- extra : convert_revision : 3ebdd496f9ffc6d1fcd1847c33e98ac23f1bfe66
Diffstat (limited to 'base')
-rw-r--r--base/chunk_generator.hh130
1 files changed, 130 insertions, 0 deletions
diff --git a/base/chunk_generator.hh b/base/chunk_generator.hh
new file mode 100644
index 000000000..83caaca88
--- /dev/null
+++ b/base/chunk_generator.hh
@@ -0,0 +1,130 @@
+/*
+ * 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(isPowerOf2(chunkSize));
+
+ // set up initial chunk.
+ curAddr = startAddr;
+
+ // 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__