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Diffstat (limited to 'backends/plugins/shorts-segment-manager.h')
-rw-r--r-- | backends/plugins/shorts-segment-manager.h | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/backends/plugins/shorts-segment-manager.h b/backends/plugins/shorts-segment-manager.h new file mode 100644 index 0000000000..54a13d88e1 --- /dev/null +++ b/backends/plugins/shorts-segment-manager.h @@ -0,0 +1,89 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + */ + +#ifndef SHORTS_SEGMENT_MANAGER_H +#define SHORTS_SEGMENT_MANAGER_H + +#include "common/singleton.h" +#include "common/list.h" +#include "elf32.h" + +#define ShortsMan ShortSegmentManager::instance() + +/** + * Manages the segments of small data put in the gp-relative area for MIPS processors, + * and lets these segments be handled differently in the ELF loader. + * Since there's no true dynamic linker to change the GP register between plugins and the main engine, + * custom linker scripts ensure the GP-area is in the same place for both. + */ +class ShortSegmentManager : public Common::Singleton<ShortSegmentManager> { +private: + char *_shortsStart; + char *_shortsEnd; + +public: + char *getShortsStart() { + return _shortsStart; + } + + // Returns whether or not an absolute address is in the GP-relative section. + bool inGeneralSegment(char *addr) { + return ((char *)addr >= _shortsStart && (char *)addr < _shortsEnd); + } + + class Segment { + private: + friend class ShortSegmentManager; + Segment(char *start, int size, char *origAddr) : _startAddress(start), _size(size), _origAddress(origAddr) {} + ~Segment() {} + char *_startAddress; // Start of shorts segment in memory + int _size; // Size of shorts segment + char *_origAddress; // Original address this segment was supposed to be at + public: + char *getStart() { + return _startAddress; + } + char *getEnd() { + return (_startAddress + _size); + } + Elf32_Addr getOffset() { + return (Elf32_Addr)(_startAddress - _origAddress); + } + bool inSegment(char *addr) { + return ((char *)addr >= _startAddress && (char *)addr <= _startAddress + _size); + } + }; + + Segment *newSegment(int size, char *origAddr); + void deleteSegment(Segment *); + +private: + ShortSegmentManager(); + friend class Common::Singleton<ShortSegmentManager>; + Common::List<Segment *> _list; + char *_highestAddress; +}; + +#endif /* SHORTS_SEGMENT_MANAGER_H */ |