SCI: Implement kMemorySegment().

svn-id: r47776

6 files changed, 52 insertions, 1 deletions

diff --git a/engines/sci/engine/kernel.cpp b/engines/sci/engine/kernel.cpp
index 27bed5b9d9..82171dc91d 100644
--- a/engines/sci/engine/kernel.cpp
+++ b/engines/sci/engine/kernel.cpp
@@ -324,6 +324,7 @@ SciKernelFunction kfunct_mappers[] = {
 	DEFUN("GetMessage", kGetMessage, "iiir"),
 	DEFUN("DoAudio", kDoAudio, ".*"),
 	DEFUN("DoSync", kDoSync, ".*"),
+	DEFUN("MemorySegment", kMemorySegment, "iri*"),
 	DEFUN("ResCheck", kResCheck, "iii*"),
 	DEFUN("SetQuitStr", kSetQuitStr, "r"),
 	DEFUN("ShowMovie", kShowMovie, "..*"),
@@ -370,7 +371,6 @@ SciKernelFunction kfunct_mappers[] = {
 	// Stub functions
 	/*09*/	DEFUN("Show", kShow, "i"),
 	DEFUN("ShiftScreen", kShiftScreen, ".*"),
-	DEFUN("MemorySegment", kMemorySegment, ".*"),
 	DEFUN("ListOps", kListOps, ".*"),
 	DEFUN("ATan", kATan, ".*"),
 	DEFUN("MergePoly", kMergePoly, ".*"),
diff --git a/engines/sci/engine/kernel.h b/engines/sci/engine/kernel.h
index baff486443..06822f4b5b 100644
--- a/engines/sci/engine/kernel.h
+++ b/engines/sci/engine/kernel.h
@@ -387,6 +387,7 @@ reg_t kGetMessage(EngineState *s, int argc, reg_t *argv);
 reg_t kMessage(EngineState *s, int argc, reg_t *argv);
 reg_t kDoAudio(EngineState *s, int argc, reg_t *argv);
 reg_t kDoSync(EngineState *s, int argc, reg_t *argv);
+reg_t kMemorySegment(EngineState *s, int argc, reg_t *argv);
 reg_t kResCheck(EngineState *s, int argc, reg_t *argv);
 reg_t kSetQuitStr(EngineState *s, int argc, reg_t *argv);
 reg_t kShowMovie(EngineState *s, int argc, reg_t *argv);
diff --git a/engines/sci/engine/kmisc.cpp b/engines/sci/engine/kmisc.cpp
index 229dcb8367..50be5509d7 100644
--- a/engines/sci/engine/kmisc.cpp
+++ b/engines/sci/engine/kmisc.cpp
@@ -121,6 +121,43 @@ reg_t kMemoryInfo(EngineState *s, int argc, reg_t *argv) {
 	return NULL_REG;
 }
 
+enum kMemorySegmentFunc {
+	K_MEMORYSEGMENT_SAVE_DATA = 0,
+	K_MEMORYSEGMENT_RESTORE_DATA = 1
+};
+
+reg_t kMemorySegment(EngineState *s, int argc, reg_t *argv) {
+	// MemorySegment provides access to a 256-byte block of memory that remains
+	// intact across restarts and restores
+
+	switch (argv[0].toUint16()) {
+	case K_MEMORYSEGMENT_SAVE_DATA: {
+		if (argc < 3)
+			error("Insufficient number of arguments passed to MemorySegment");
+		uint16 size = argv[2].toUint16();
+
+		if (!size)
+			size = s->_segMan->strlen(argv[1]) + 1;
+
+		if (size > EngineState::kMemorySegmentMax)
+			size = EngineState::kMemorySegmentMax;
+
+		s->_memorySegmentSize = size;
+
+		// We assume that this won't be called on pointers
+		s->_segMan->memcpy(s->_memorySegment, argv[1], size);
+		break;
+	}
+	case K_MEMORYSEGMENT_RESTORE_DATA:
+		s->_segMan->memcpy(argv[1], s->_memorySegment, s->_memorySegmentSize);
+		break;
+	default:
+		error("Unknown MemorySegment operation %04x", argv[0].toUint16());
+	}
+
+	return argv[1];
+}
+
 reg_t kFlushResources(EngineState *s, int argc, reg_t *argv) {
 	run_gc(s);
 	debugC(2, kDebugLevelRoom, "Entering room number %d", argv[0].toUint16());
diff --git a/engines/sci/engine/savegame.cpp b/engines/sci/engine/savegame.cpp
index 9c0fd9dc47..9d36914c4a 100644
--- a/engines/sci/engine/savegame.cpp
+++ b/engines/sci/engine/savegame.cpp
@@ -952,6 +952,10 @@ void gamestate_restore(EngineState *s, Common::SeekableReadStream *fh) {
 	// Copy some old data
 	retval->_soundCmd = s->_soundCmd;
 
+	// Copy memory segment
+	retval->_memorySegmentSize = s->_memorySegmentSize;
+	memcpy(retval->_memorySegment, s->_memorySegment, s->_memorySegmentSize);
+
 	retval->saveLoadWithSerializer(ser);	// FIXME: Error handling?
 
 #ifdef USE_OLD_MUSIC_FUNCTIONS
diff --git a/engines/sci/engine/state.cpp b/engines/sci/engine/state.cpp
index 81d9fe9449..a773894254 100644
--- a/engines/sci/engine/state.cpp
+++ b/engines/sci/engine/state.cpp
@@ -84,6 +84,8 @@ EngineState::EngineState(ResourceManager *res, Kernel *kernel, Vocabulary *voc,
 	_sci21KernelType = SCI_VERSION_NONE;
 #endif
 
+	_memorySegmentSize = 0;
+
 	_usesCdTrack = Common::File::exists("cdaudio.map");
 
 	_soundCmd = 0;
diff --git a/engines/sci/engine/state.h b/engines/sci/engine/state.h
index 299e6ac1d6..9d7a7a5ab4 100644
--- a/engines/sci/engine/state.h
+++ b/engines/sci/engine/state.h
@@ -140,6 +140,10 @@ public:
 	EngineState(ResourceManager *res, Kernel *kernel, Vocabulary *voc, SegManager *segMan, SciGui *gui, AudioPlayer *audio);
 	virtual ~EngineState();
 
+	enum {
+		kMemorySegmentMax = 256
+	};
+
 	virtual void saveLoadWithSerializer(Common::Serializer &ser);
 
 	kLanguage getLanguage();
@@ -287,6 +291,9 @@ public:
 
 	MessageState *_msgState;
 
+	uint _memorySegmentSize;
+	byte _memorySegment[kMemorySegmentMax];
+
 	EngineState *successor; /**< Successor of this state: Used for restoring */
 
 	Common::String getLanguageString(const char *str, kLanguage lang) const;