We have several functions where we need to find the pointer to a program or an

instrument. These are found using the lookup tables in _soundData on offsets 0
and 500 respectively. Added helper functions for that, which makes the code a
lot tidier. Particularly in update_setupRhythmSection(), where it's now much
clearer where it's getting all those "unk" values from.

Use the checkValue() function (which limits the "total level" to its valid
range) for the calculateOpLevel1() and 2() functions as well.

Renamed updateCallback16() to update_waitForEndOfProgram().

svn-id: r21337

1 files changed, 39 insertions, 51 deletions

diff --git a/engines/kyra/sound_adlib.cpp b/engines/kyra/sound_adlib.cpp
index 3bb5e99f43..24299abdcb 100644
--- a/engines/kyra/sound_adlib.cpp
+++ b/engines/kyra/sound_adlib.cpp
@@ -204,11 +204,24 @@ private:
 	uint16 checkValue(int16 val) {
 		if (val < 0)
 			val = 0;
-		if (val > 0x3F)
+		else if (val > 0x3F)
 			val = 0x3F;
 		return val;
 	}
 
+	// The sound data has at least two lookup tables:
+	//
+	// * One for programs, starting at offset 0.
+	// * One for instruments, starting at offset 500.
+
+	uint8 *getProgram(int progId) {
+		return _soundData + READ_LE_UINT16(_soundData + 2 * progId);
+	}
+
+	uint8 *getInstrument(int instrumentId) {
+		return _soundData + READ_LE_UINT16(_soundData + 500 + 2 * instrumentId);
+	}
+
 	void setupPrograms();
 	void executePrograms();
 
@@ -235,7 +248,7 @@ private:
 	int update_setBaseNote(uint8 *&dataptr, Channel &channel, uint8 value);
 	int update_setupSecondaryEffect1(uint8 *&dataptr, Channel &channel, uint8 value);
 	int update_stopOtherChannel(uint8 *&dataptr, Channel &channel, uint8 value);
-	int updateCallback16(uint8 *&dataptr, Channel &channel, uint8 value);
+	int update_waitForEndOfProgram(uint8 *&dataptr, Channel &channel, uint8 value);
 	int update_setupInstrument(uint8 *&dataptr, Channel &channel, uint8 value);
 	int update_setupPrimaryEffect1(uint8 *&dataptr, Channel &channel, uint8 value);
 	int update_removePrimaryEffect1(uint8 *&dataptr, Channel &channel, uint8 value);
@@ -468,11 +481,12 @@ int AdlibDriver::snd_startSong(va_list &list) {
 	int songId = va_arg(list, int);
 	_flags |= 8;
 	_flagTrigger = 1;
-	uint16 offset = READ_LE_UINT16(&_soundData[songId << 1]);
-	uint8 firstByte = *(_soundData + offset);
+
+	uint8 *ptr = getProgram(songId);
+	uint8 chan = *ptr;
 
 	if ((songId << 1) != 0) {
-		if (firstByte == 9) {
+		if (chan == 9) {
 			if (_flags & 2)
 				return 0;
 		} else {
@@ -593,8 +607,7 @@ void AdlibDriver::callback() {
 
 void AdlibDriver::setupPrograms() {
 	while (_lastProcessed != _soundsPlaying) {
-		uint16 add = _soundIdTable[_lastProcessed] << 1;
-		uint8 *ptr = _soundData + READ_LE_UINT16(_soundData + add);
+		uint8 *ptr = getProgram(_soundIdTable[_lastProcessed]);
 		uint8 chan = *ptr++;
 		uint8 priority = *ptr++;
 
@@ -1152,16 +1165,9 @@ uint8 AdlibDriver::calculateOpLevel1(Channel &channel) {
 		value += channel.opExtraLevel3;
 	}
 
-	// Don't allow the total level to overflow into the scaling level bits.
-
-	if (value > 0x3F) {
-		value = 0x3F;
-	} else if (value < 0)
-		value = 0;
-
 	// Preserve the scaling level bits from opLevel1
 
-	return value | (channel.opLevel1 & 0xC0);
+	return checkValue(value) | (channel.opLevel1 & 0xC0);
 }
 
 uint8 AdlibDriver::calculateOpLevel2(Channel &channel) {
@@ -1171,16 +1177,9 @@ uint8 AdlibDriver::calculateOpLevel2(Channel &channel) {
 	value += channel.opExtraLevel2;
 	value += channel.opExtraLevel3;
 
-	// Don't allow the total level to overflow into the scaling level bits.
-
-	if (value > 0x3F) {
-		value = 0x3F;
-	} else if (value < 0)
-		value = 0;
-
 	// Preserve the scaling level bits from opLevel2
 
-	return value | (channel.opLevel2 & 0xC0);
+	return checkValue(value) | (channel.opLevel2 & 0xC0);
 }
 
 // parser opcodes
@@ -1203,8 +1202,7 @@ int AdlibDriver::update_setupProgram(uint8 *&dataptr, Channel &channel, uint8 va
 	if (value == 0xFF)
 		return 0;
 
-	uint16 add = value << 1;
-	uint8 *ptr = _soundData + READ_LE_UINT16(_soundData + add);
+	uint8 *ptr = getProgram(value);
 	uint8 chan = *ptr++;
 	uint8 priority = *ptr++;
 
@@ -1304,21 +1302,20 @@ int AdlibDriver::update_stopOtherChannel(uint8 *&dataptr, Channel &channel, uint
 	return 0;
 }
 
-int AdlibDriver::updateCallback16(uint8 *&dataptr, Channel &channel, uint8 value) {
-	uint8 *ptr = _soundData;
-	ptr += READ_LE_UINT16(&_soundData[value << 1]);
-	Channel &channel2 = _channels[*ptr];
-	if (!channel2.dataptr) {
+int AdlibDriver::update_waitForEndOfProgram(uint8 *&dataptr, Channel &channel, uint8 value) {
+	uint8 *ptr = getProgram(value);
+	uint8 chan = *ptr;
+
+	if (!_channels[chan].dataptr) {
 		return 0;
 	}
+
 	dataptr -= 2;
 	return 2;
 }
 
 int AdlibDriver::update_setupInstrument(uint8 *&dataptr, Channel &channel, uint8 value) {
-	uint8 *ptr = _soundData;
-	ptr += READ_LE_UINT16(_soundData + (value << 1) + 0x1F4);
-	setupInstrument(_curRegOffset, ptr, channel);
+	setupInstrument(_curRegOffset, getInstrument(value), channel);
 	return 0;
 }
 
@@ -1592,34 +1589,25 @@ int AdlibDriver::update_setupRhythmSection(uint8 *&dataptr, Channel &channel, ui
 	int channelBackUp = _curChannel;
 	int regOffsetBackUp = _curRegOffset;
 
-	uint8 entry = value << 1;
-	uint8 *ptr = _soundData + READ_LE_UINT16(_soundData + entry + 0x1F4);
-
 	_curChannel = 6;
 	_curRegOffset = _regOffset[6];
 
-	_unkValue6 = *(ptr + 6);
-	setupInstrument(_curRegOffset, ptr, channel);
-
-	entry = *dataptr++ << 1;
-	ptr = _soundData + READ_LE_UINT16(_soundData + entry + 0x1F4);
+	setupInstrument(_curRegOffset, getInstrument(value), channel);
+	_unkValue6 = channel.opLevel2;
 
 	_curChannel = 7;
 	_curRegOffset = _regOffset[7];
 
-	_unkValue7 = entry = *(ptr + 5);
-	_unkValue8 = entry = *(ptr + 6);
-	setupInstrument(_curRegOffset, ptr, channel);
-
-	entry = *dataptr++ << 1;
-	ptr = _soundData + READ_LE_UINT16(_soundData + entry + 0x1F4);
+	setupInstrument(_curRegOffset, getInstrument(*dataptr++), channel);
+	_unkValue7 = channel.opLevel1;
+	_unkValue8 = channel.opLevel2;
 
 	_curChannel = 8;
 	_curRegOffset = _regOffset[8];
 
-	_unkValue9 = entry = *(ptr + 5);
-	_unkValue10 = entry = *(ptr + 6);
-	setupInstrument(_curRegOffset, ptr, channel);
+	setupInstrument(_curRegOffset, getInstrument(*dataptr++), channel);
+	_unkValue9 = channel.opLevel1;
+	_unkValue10 = channel.opLevel2;
 
 	// Octave / F-Number / Key-On for channels 6, 7 and 8
 
@@ -1905,7 +1893,7 @@ const AdlibDriver::ParserOpcode AdlibDriver::_parserOpcodeTable[] = {
 	COMMAND(update_setBaseNote),
 	COMMAND(update_setupSecondaryEffect1),
 	COMMAND(update_stopOtherChannel),
-	COMMAND(updateCallback16),
+	COMMAND(update_waitForEndOfProgram),
 
 	// 16
 	COMMAND(update_setupInstrument),