dgrove@google.com
4c0f559d23
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@15 260f80e4-7a28-3924-810f-c04153c831b5
41 lines
1.3 KiB
C++
41 lines
1.3 KiB
C++
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "vm/virtual_memory.h"
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#include "vm/assert.h"
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#include "vm/utils.h"
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namespace dart {
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VirtualMemory* VirtualMemory::ReserveAligned(intptr_t size,
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intptr_t alignment) {
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ASSERT((size & (PageSize() - 1)) == 0);
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ASSERT(Utils::IsPowerOfTwo(alignment));
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ASSERT(alignment >= PageSize());
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VirtualMemory* result = VirtualMemory::Reserve(size + alignment);
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uword start = result->start();
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uword real_start = (start + alignment - 1) & ~(alignment - 1);
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result->Truncate(real_start, size);
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return result;
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}
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void VirtualMemory::Truncate(uword new_start, intptr_t new_size) {
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ASSERT(new_start >= start());
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ASSERT((new_size & (PageSize() - 1)) == 0);
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if (new_start > start()) {
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uword split = new_start - start();
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ASSERT((split & (PageSize() - 1)) == 0);
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FreeSubSegment(address(), split);
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region_.Subregion(region_, split, size() - split);
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}
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ASSERT(new_size <= size());
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FreeSubSegment(reinterpret_cast<void*>(start() + new_size),
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size() - new_size);
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region_.Subregion(region_, 0, new_size);
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}
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} // namespace dart
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