GOB: Gave tons of opcode explicit names. As a result, found potential bugs in parse_v2.cpp (related to OP_LOAD_VAR_UINT8 and OP_LOAD_VAR_UINT16, see FIXME comments in parse.h)

svn-id: r39889

4 files changed, 379 insertions, 314 deletions

diff --git a/engines/gob/parse.cpp b/engines/gob/parse.cpp
index 3dfcc0bb47..7bcdfb4f79 100644
--- a/engines/gob/parse.cpp
+++ b/engines/gob/parse.cpp
@@ -82,10 +82,10 @@ void Parse::skipExpr(char stopToken) {
 	int16 dim;
 
 	num = 0;
-	while (1) {
+	while (true) {
 		operation = *_vm->_global->_inter_execPtr++;
 
-		if ((operation >= 14) && (operation <= 29)) {
+		if ((operation >= 14) && (operation <= OP_FUNC)) {
 			switch (operation) {
 			case 14:
 				_vm->_global->_inter_execPtr += 4;
@@ -95,26 +95,26 @@ void Parse::skipExpr(char stopToken) {
 
 			case 17:
 			case 18:
-			case 20:
+			case OP_LOAD_IMM_INT16:
 			case 23:
 			case 24:
 				_vm->_global->_inter_execPtr += 2;
 				break;
 
-			case 19:
+			case OP_LOAD_IMM_INT32:
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 21:
+			case OP_LOAD_IMM_INT8:
 				_vm->_global->_inter_execPtr += 1;
 				break;
 
-			case 22:
+			case OP_LOAD_IMM_STR:
 				_vm->_global->_inter_execPtr +=
 					strlen((char *) _vm->_global->_inter_execPtr) + 1;
 				break;
 
-			case 25:
+			case OP_LOAD_VAR_STR:
 				_vm->_global->_inter_execPtr += 2;
 				if (*_vm->_global->_inter_execPtr == 13) {
 					_vm->_global->_inter_execPtr++;
@@ -125,10 +125,10 @@ void Parse::skipExpr(char stopToken) {
 			case 15:
 				_vm->_global->_inter_execPtr += 2;
 
-			case 16:
-			case 26:
-			case 27:
-			case 28:
+			case OP_ARRAY_UINT8:
+			case OP_ARRAY_UINT32:
+			case OP_ARRAY_UINT16:
+			case OP_ARRAY_STR:
 				dimCount = _vm->_global->_inter_execPtr[2];
 				// skip header and dimensions
 				_vm->_global->_inter_execPtr += 3 + dimCount;
@@ -136,31 +136,31 @@ void Parse::skipExpr(char stopToken) {
 				for (dim = 0; dim < dimCount; dim++)
 					skipExpr(12);
 
-				if ((operation == 28) && (*_vm->_global->_inter_execPtr == 13)) {
+				if ((operation == OP_ARRAY_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 					_vm->_global->_inter_execPtr++;
 					skipExpr(12);
 				}
 				break;
 
-			case 29:
+			case OP_FUNC:
 				_vm->_global->_inter_execPtr++;
 				skipExpr(10);
 			}
 			continue;
-		} // if ((operation >= 16) && (operation <= 29))
+		} // if ((operation >= OP_ARRAY_UINT8) && (operation <= OP_FUNC))
 
-		if (operation == 9) {
+		if (operation == OP_BEGIN_EXPR) {
 			num++;
 			continue;
 		}
 
-		if ((operation == 11) || ((operation >= 1) && (operation <= 8)))
+		if ((operation == OP_NOT) || ((operation >= OP_NEG) && (operation <= 8)))
 			continue;
 
-		if ((operation >= 30) && (operation <= 37))
+		if ((operation >= OP_OR) && (operation <= OP_NEQ))
 			continue;
 
-		if (operation == 10)
+		if (operation == OP_END_EXPR)
 			num--;
 
 		if (operation != stopToken)
@@ -191,10 +191,10 @@ void Parse::printExpr_internal(char stopToken) {
 	byte func;
 
 	num = 0;
-	while (1) {
+	while (true) {
 		operation = *_vm->_global->_inter_execPtr++;
 
-		if ((operation >= 16) && (operation <= 29)) {
+		if ((operation >= OP_ARRAY_UINT8) && (operation <= OP_FUNC)) {
 			// operands
 
 			switch (operation) {
@@ -206,20 +206,20 @@ void Parse::printExpr_internal(char stopToken) {
 				debugN(5, "var8_%d", _vm->_inter->load16());
 				break;
 
-			case 19: // int32/uint32 immediate
+			case OP_LOAD_IMM_INT32: // int32/uint32 immediate
 				debugN(5, "%d", READ_LE_UINT32(_vm->_global->_inter_execPtr));
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 20: // int16 immediate
+			case OP_LOAD_IMM_INT16: // int16 immediate
 				debugN(5, "%d", _vm->_inter->load16());
 				break;
 
-			case 21: // int8 immediate
+			case OP_LOAD_IMM_INT8: // int8 immediate
 				debugN(5, "%d", (int8) *_vm->_global->_inter_execPtr++);
 				break;
 
-			case 22: // string immediate
+			case OP_LOAD_IMM_STR: // string immediate
 				debugN(5, "\42%s\42", _vm->_global->_inter_execPtr);
 				_vm->_global->_inter_execPtr +=
 					strlen((char *) _vm->_global->_inter_execPtr) + 1;
@@ -230,7 +230,7 @@ void Parse::printExpr_internal(char stopToken) {
 				debugN(5, "var_%d", _vm->_inter->load16());
 				break;
 
-			case 25: // string variable load
+			case OP_LOAD_VAR_STR: // string variable load
 				debugN(5, "(&var_%d)", _vm->_inter->load16());
 				if (*_vm->_global->_inter_execPtr == 13) {
 					_vm->_global->_inter_execPtr++;
@@ -239,12 +239,12 @@ void Parse::printExpr_internal(char stopToken) {
 				}
 				break;
 
-			case 16: // uint8 array access
-			case 26: // uint32 array access
-			case 27: // uint16 array access
-			case 28: // string array access
+			case OP_ARRAY_UINT8: // uint8 array access
+			case OP_ARRAY_UINT32: // uint32 array access
+			case OP_ARRAY_UINT16: // uint16 array access
+			case OP_ARRAY_STR: // string array access
 				debugN(5, "\n");
-				if (operation == 28)
+				if (operation == OP_ARRAY_STR)
 					debugN(5, "(&");
 
 				debugN(5, "var_%d[", _vm->_inter->load16());
@@ -258,25 +258,25 @@ void Parse::printExpr_internal(char stopToken) {
 						debugN(5, ",");
 				}
 				debugN(5, "]");
-				if (operation == 28)
+				if (operation == OP_ARRAY_STR)
 					debugN(5, ")");
 
-				if ((operation == 28) && (*_vm->_global->_inter_execPtr == 13)) {
+				if ((operation == OP_ARRAY_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 					_vm->_global->_inter_execPtr++;
 					debugN(5, "{");
 					printExpr_internal(12); // this also prints the closing }
 				}
 				break;
 
-			case 29: // function
+			case OP_FUNC: // function
 				func = *_vm->_global->_inter_execPtr++;
-				if (func == 5)
+				if (func == FUNC_SQR)
 					debugN(5, "sqr(");
-				else if (func == 10)
+				else if (func == FUNC_RAND)
 					debugN(5, "rand(");
-				else if (func == 7)
+				else if (func == FUNC_ABS)
 					debugN(5, "abs(");
-				else if ((func == 0) || (func == 1) || (func == 6))
+				else if ((func == FUNC_SQRT1) || (func == FUNC_SQRT2) || (func == FUNC_SQRT3))
 					debugN(5, "sqrt(");
 				else
 					debugN(5, "id(");
@@ -284,23 +284,23 @@ void Parse::printExpr_internal(char stopToken) {
 				break;
 			}
 			continue;
-		}		// if ((operation >= 16) && (operation <= 29))
+		}		// if ((operation >= OP_ARRAY_UINT8) && (operation <= OP_FUNC))
 
 		// operators
 		switch (operation) {
-		case 9:
+		case OP_BEGIN_EXPR:
 			debugN(5, "(");
 			break;
 
-		case 11:
+		case OP_NOT:
 			debugN(5, "!");
 			break;
 
-		case 10:
+		case OP_END_EXPR:
 			debugN(5, ")");
 			break;
 
-		case 1:
+		case OP_NEG:
 			debugN(5, "-");
 			break;
 
@@ -332,7 +332,7 @@ void Parse::printExpr_internal(char stopToken) {
 			debugN(5, "&");
 			break;
 
-		case 30:
+		case OP_OR:
 			debugN(5, "||");
 			break;
 
@@ -340,27 +340,27 @@ void Parse::printExpr_internal(char stopToken) {
 			debugN(5, "&&");
 			break;
 
-		case 32:
+		case OP_LESS:
 			debugN(5, "<");
 			break;
 
-		case 33:
+		case OP_LEQ:
 			debugN(5, "<=");
 			break;
 
-		case 34:
+		case OP_GREATER:
 			debugN(5, ">");
 			break;
 
-		case 35:
+		case OP_GEQ:
 			debugN(5, ">=");
 			break;
 
-		case 36:
+		case OP_EQ:
 			debugN(5, "==");
 			break;
 
-		case 37:
+		case OP_NEQ:
 			debugN(5, "!=");
 			break;
 
@@ -381,18 +381,18 @@ void Parse::printExpr_internal(char stopToken) {
 			break;
 		}
 
-		if (operation == 9) {
+		if (operation == OP_BEGIN_EXPR) {
 			num++;
 			continue;
 		}
 
-		if ((operation == 11) || ((operation >= 1) && (operation <= 8)))
+		if ((operation == OP_NOT) || ((operation >= OP_NEG) && (operation <= 8)))
 			continue;
 
-		if ((operation >= 30) && (operation <= 37))
+		if ((operation >= OP_OR) && (operation <= OP_NEQ))
 			continue;
 
-		if (operation == 10)
+		if (operation == OP_END_EXPR)
 			num--;
 
 		if (operation == stopToken) {
@@ -416,18 +416,18 @@ void Parse::printVarIndex() {
 	operation = *_vm->_global->_inter_execPtr++;
 	switch (operation) {
 	case 23:
-	case 25:
+	case OP_LOAD_VAR_STR:
 		temp = _vm->_inter->load16() * 4;
 		debugN(5, "&var_%d", temp);
-		if ((operation == 25) && (*_vm->_global->_inter_execPtr == 13)) {
+		if ((operation == OP_LOAD_VAR_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 			_vm->_global->_inter_execPtr++;
 			debugN(5, "+");
 			printExpr(12);
 		}
 		break;
 
-	case 26:
-	case 28:
+	case OP_ARRAY_UINT32:
+	case OP_ARRAY_STR:
 		debugN(5, "&var_%d[", _vm->_inter->load16());
 		dimCount = *_vm->_global->_inter_execPtr++;
 		arrDesc = _vm->_global->_inter_execPtr;
@@ -440,7 +440,7 @@ void Parse::printVarIndex() {
 		}
 		debugN(5, "]");
 
-		if ((operation == 28) && (*_vm->_global->_inter_execPtr == 13)) {
+		if ((operation == OP_ARRAY_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 			_vm->_global->_inter_execPtr++;
 			debugN(5, "+");
 			printExpr(12);
@@ -459,9 +459,9 @@ void Parse::printVarIndex() {
 int Parse::cmpHelper(byte *operPtr, int32 *valPtr) {
 	byte var_C = operPtr[-3];
 	int cmpTemp;
-	if (var_C == 20) {
+	if (var_C == OP_LOAD_IMM_INT16) {
 		cmpTemp = (int)valPtr[-3] - (int)valPtr[-1];
-	} else if (var_C == 22) {
+	} else if (var_C == OP_LOAD_IMM_STR) {
 		if ((char *)decodePtr(valPtr[-3]) != _vm->_global->_inter_resStr) {
 			strcpy(_vm->_global->_inter_resStr, (char *)decodePtr(valPtr[-3]));
 			valPtr[-3] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);
diff --git a/engines/gob/parse.h b/engines/gob/parse.h
index 9bd8f6afab..e0696fa0bb 100644
--- a/engines/gob/parse.h
+++ b/engines/gob/parse.h
@@ -29,13 +29,70 @@
 namespace Gob {
 
 enum {
+	OP_NEG = 1,
 	OP_ADD = 2,
 	OP_SUB = 3,
 	OP_BITOR = 4,
 	OP_MUL = 5,
 	OP_DIV = 6,
 	OP_MOD = 7,
-	OP_BITAND = 8
+	OP_BITAND = 8,
+	OP_BEGIN_EXPR = 9,
+	OP_END_EXPR = 10,
+	OP_NOT = 11,
+
+
+	OP_ARRAY_UINT8 = 16,
+
+	// FIXME: OP_LOAD_VAR_UINT16 comment says "uint16 variable load" in
+	// Parse::printExpr_internal, and does that in Parse_v2::parseExpr,
+	// but reads int8 in Parse_v2::parseValExpr
+	OP_LOAD_VAR_UINT16 = 17,
+	// FIXME: OP_LOAD_VAR_UINT8 comment says "uint8 variable load" in
+	// Parse::printExpr_internal, but reads int8 in Parse_v2::parseValExpr
+	OP_LOAD_VAR_UINT8 = 18,
+	OP_LOAD_IMM_INT32 = 19,
+	OP_LOAD_IMM_INT16 = 20,
+	OP_LOAD_IMM_INT8 = 21,
+	OP_LOAD_IMM_STR = 22,
+
+	OP_LOAD_VAR_UINT32 = 23,		// ???
+	OP_LOAD_VAR_UINT32_AS_UINT16 = 24,		// ???
+	OP_LOAD_VAR_STR = 25,
+
+	OP_ARRAY_UINT32 = 26,
+	OP_ARRAY_UINT16 = 27,
+	OP_ARRAY_STR = 28,
+
+	OP_FUNC = 29,
+
+	OP_OR = 30,	// Logical OR
+	OP_AND = 31,	// Logical AND
+	OP_LESS = 32,
+	OP_LEQ = 33,
+	OP_GREATER = 34,
+	OP_GEQ = 35,
+	OP_EQ = 36,
+	OP_NEQ = 37
+};
+
+enum {
+	FUNC_SQRT1 = 0,
+	FUNC_SQRT2 = 1,
+	FUNC_SQRT3 = 6,
+
+	FUNC_SQR = 5,
+	FUNC_ABS = 7,
+	FUNC_RAND = 10
+};
+
+enum {
+	// FIXME: The following two 'truth values' are stored inside the list
+	// of "operators". So they somehow coincide with OP_LOAD_VAR_UINT32
+	// and OP_LOAD_VAR_UINT32_AS_UINT16. I haven't yet quite understood 
+	// how, resp. what that means. You have been warned.
+	GOB_TRUE = 24,
+	GOB_FALSE = 23
 };
 
 class Parse {
diff --git a/engines/gob/parse_v1.cpp b/engines/gob/parse_v1.cpp
index d25b2beb23..5352e9a611 100644
--- a/engines/gob/parse_v1.cpp
+++ b/engines/gob/parse_v1.cpp
@@ -49,12 +49,12 @@ int16 Parse_v1::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 	debugC(5, kDebugParser, "var parse = %d", operation);
 	switch (operation) {
 	case 23:
-	case 25:
+	case OP_LOAD_VAR_STR:
 		temp = _vm->_inter->load16() * 4;
 		debugC(5, kDebugParser, "oper = %d",
 				(int16) *_vm->_global->_inter_execPtr);
 
-		if ((operation == 25) && (*_vm->_global->_inter_execPtr == 13)) {
+		if ((operation == OP_LOAD_VAR_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 			_vm->_global->_inter_execPtr++;
 			val = parseValExpr(12);
 			temp += val;
@@ -62,8 +62,8 @@ int16 Parse_v1::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 		}
 		return temp;
 
-	case 26:
-	case 28:
+	case OP_ARRAY_UINT32:
+	case OP_ARRAY_STR:
 		temp = _vm->_inter->load16() * 4;
 		dimCount = *_vm->_global->_inter_execPtr++;
 		arrDesc = _vm->_global->_inter_execPtr;
@@ -74,7 +74,7 @@ int16 Parse_v1::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 			offset = arrDesc[dim] * offset + temp2;
 		}
 		offset *= 4;
-		if (operation != 28)
+		if (operation != OP_ARRAY_STR)
 			return temp + offset;
 
 		if (*_vm->_global->_inter_execPtr == 13) {
@@ -115,21 +115,21 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 	operPtr = operStack - 1;
 	valPtr = values - 1;
 
-	while (1) {
+	while (true) {
 		stkPos++;
 		operPtr++;
 		valPtr++;
 
 		operation = *_vm->_global->_inter_execPtr++;
-		if ((operation >= 19) && (operation <= 29)) {
-			*operPtr = 20;
+		if ((operation >= OP_LOAD_IMM_INT32) && (operation <= OP_FUNC)) {
+			*operPtr = OP_LOAD_IMM_INT16;
 			switch (operation) {
-			case 19:
+			case OP_LOAD_IMM_INT32:
 				*valPtr = READ_LE_UINT32(_vm->_global->_inter_execPtr);
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 20:
+			case OP_LOAD_IMM_INT16:
 				*valPtr = _vm->_inter->load16();
 				break;
 
@@ -137,15 +137,15 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 				*valPtr = (uint16) VAR(_vm->_inter->load16());
 				break;
 
-			case 25:
+			case OP_LOAD_VAR_STR:
 				temp = _vm->_inter->load16() * 4;
 				_vm->_global->_inter_execPtr++;
 				temp += parseValExpr(12);
 				*valPtr = READ_VARO_UINT8(temp);
 				break;
 
-			case 26:
-			case 28:
+			case OP_ARRAY_UINT32:
+			case OP_ARRAY_STR:
 				temp = _vm->_inter->load16();
 				dimCount = *_vm->_global->_inter_execPtr++;
 				arrDesc = _vm->_global->_inter_execPtr;
@@ -155,7 +155,7 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 					temp2 = parseValExpr(12);
 					offset = arrDesc[dim] * offset + temp2;
 				}
-				if (operation == 26) {
+				if (operation == OP_ARRAY_UINT32) {
 					*valPtr = (uint16) VAR(temp + offset);
 				} else {
 					_vm->_global->_inter_execPtr++;
@@ -165,17 +165,17 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 				}
 				break;
 
-			case 29:
+			case OP_FUNC:
 				operation = *_vm->_global->_inter_execPtr++;
 				parseExpr(10, 0);
 
-				if (operation == 5) {
+				if (operation == FUNC_SQR) {
 					_vm->_global->_inter_resVal =
 						_vm->_global->_inter_resVal * _vm->_global->_inter_resVal;
-				} else if (operation == 7) {
+				} else if (operation == FUNC_ABS) {
 					if (_vm->_global->_inter_resVal < 0)
 						_vm->_global->_inter_resVal = -_vm->_global->_inter_resVal;
-				} else if (operation == 10) {
+				} else if (operation == FUNC_RAND) {
 					_vm->_global->_inter_resVal =
 						_vm->_util->getRandom(_vm->_global->_inter_resVal);
 				}
@@ -183,15 +183,15 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 				break;
 
 			}	// switch
-			if ((stkPos > 0) && (operPtr[-1] == 1)) {
+			if ((stkPos > 0) && (operPtr[-1] == OP_NEG)) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
-				operPtr[0] = 20;
+				operPtr[0] = OP_LOAD_IMM_INT16;
 				valPtr[0] = -valPtr[1];
 			}
 
-			if ((stkPos > 0) && (operPtr[-1] > 4) && (operPtr[-1] < 9)) {
+			if ((stkPos > 0) && (operPtr[-1] >= OP_MUL) && (operPtr[-1] <= OP_BITAND)) {
 				stkPos -= 2;
 				operPtr -= 2;
 				valPtr -= 2;
@@ -213,25 +213,25 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 					valPtr[0] &= valPtr[2];
 					break;
 				}
-			}	// if ((stkPos > 0) && (cmdPtr[-1] > 4) && (cmdPtr[-1] < 9))
+			}	// if ((stkPos > 0) && (cmdPtr[-1] >= OP_MUL) && (cmdPtr[-1] <= OP_BITAND))
 			continue;
 		}
 
-		if ((operation >= 1) && (operation <= 9)) {
+		if ((operation >= OP_NEG) && (operation <= OP_BEGIN_EXPR)) {
 			*operPtr = operation;
 			continue;
 		}
 
 		while (stkPos >= 2) {
-			if (operPtr[-2] == 9) {
+			if (operPtr[-2] == OP_BEGIN_EXPR) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
 
 				operPtr[-1] = operPtr[0];
 				valPtr[-1] = valPtr[0];
-				if ((stkPos > 1) && (operPtr[-2] == 1)) {
-					valPtr[-2] = 20;
+				if ((stkPos > 1) && (operPtr[-2] == OP_NEG)) {
+					valPtr[-2] = OP_LOAD_IMM_INT16;
 					valPtr[-2] = -valPtr[-1];
 
 					stkPos--;
@@ -239,7 +239,7 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 					valPtr--;
 				}
 
-				if ((stkPos > 2) && (operPtr[-2] > 4) && (operPtr[-2] < 9)) {
+				if ((stkPos > 2) && (operPtr[-2] >= OP_MUL) && (operPtr[-2] <= OP_BITAND)) {
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
@@ -261,16 +261,16 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 						break;
 					}
 				}
-				if (operation == 10)
+				if (operation == OP_END_EXPR)
 					break;
-			}	// operPtr[-2] == 9
+			}	// operPtr[-2] == OP_BEGIN_EXPR
 
 			for (brackPos = (stkPos - 2); (brackPos > 0) &&
-			    (operStack[brackPos] < 30) && (operStack[brackPos] != 9);
+			    (operStack[brackPos] < OP_OR) && (operStack[brackPos] != OP_BEGIN_EXPR);
 					brackPos--)
 				;
 
-			if ((operStack[brackPos] >= 30) || (operStack[brackPos] == 9))
+			if ((operStack[brackPos] >= OP_OR) || (operStack[brackPos] == OP_BEGIN_EXPR))
 				brackPos++;
 
 			if ((operPtr[-2] < 2) || (operPtr[-2] > 8))
@@ -304,7 +304,7 @@ int16 Parse_v1::parseValExpr(byte stopToken) {
 			}
 		}
 
-		if (operation != 10) {
+		if (operation != OP_END_EXPR) {
 			if (operation != stopToken)
 				debugC(5, kDebugParser, "stoptoken error: %d != %d",
 						operation, stopToken);
@@ -342,51 +342,51 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 	operPtr = operStack - 1;
 	valPtr = values - 1;
 
-	while (1) {
+	while (true) {
 		stkPos++;
 		operPtr++;
 		valPtr++;
 		operation = *_vm->_global->_inter_execPtr++;
-		if ((operation >= 19) && (operation <= 29)) {
+		if ((operation >= OP_LOAD_IMM_INT32) && (operation <= OP_FUNC)) {
 			switch (operation) {
-			case 19:
-				*operPtr = 20;
+			case OP_LOAD_IMM_INT32:
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = READ_LE_UINT32(_vm->_global->_inter_execPtr);
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 20:
-				*operPtr = 20;
+			case OP_LOAD_IMM_INT16:
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = _vm->_inter->load16();
 				break;
 
-			case 22:
-				*operPtr = 22;
+			case OP_LOAD_IMM_STR:
+				*operPtr = OP_LOAD_IMM_STR;
 				*valPtr = encodePtr(_vm->_global->_inter_execPtr, kExecPtr);
 				_vm->_global->_inter_execPtr +=
 					strlen((char *) _vm->_global->_inter_execPtr) + 1;
 				break;
 
 			case 23:
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = VAR(_vm->_inter->load16());
 				break;
 
-			case 25:
-				*operPtr = 22;
+			case OP_LOAD_VAR_STR:
+				*operPtr = OP_LOAD_IMM_STR;
 				temp = _vm->_inter->load16() * 4;
 				*valPtr = encodePtr(_vm->_inter->_variables->getAddressOff8(temp, 0),
 						kInterVar);
 				if (*_vm->_global->_inter_execPtr == 13) {
 					_vm->_global->_inter_execPtr++;
 					temp += parseValExpr(12);
-					*operPtr = 20;
+					*operPtr = OP_LOAD_IMM_INT16;
 					*valPtr = READ_VARO_UINT8(temp);
 				}
 				break;
 
-			case 26:
-			case 28:
+			case OP_ARRAY_UINT32:
+			case OP_ARRAY_STR:
 				*operPtr = operation - 6;
 				temp = _vm->_inter->load16();
 				dimCount = *_vm->_global->_inter_execPtr++;
@@ -399,7 +399,7 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 					offset = offset * arrDescPtr[dim] + temp2;
 				}
 
-				if (operation == 26) {
+				if (operation == OP_ARRAY_UINT32) {
 					*valPtr = VAR(temp + offset);
 					break;
 				}
@@ -409,25 +409,25 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 				if (*_vm->_global->_inter_execPtr == 13) {
 					_vm->_global->_inter_execPtr++;
 					temp2 = parseValExpr(12);
-					*operPtr = 20;
+					*operPtr = OP_LOAD_IMM_INT16;
 					*valPtr = READ_VARO_UINT8(temp * 4 +
 							offset * 4 * _vm->_global->_inter_animDataSize + temp2);
 				}
 				break;
 
-			case 29:
+			case OP_FUNC:
 				operation = *_vm->_global->_inter_execPtr++;
 				parseExpr(10, 0);
 
 				switch (operation) {
-				case 5:
+				case FUNC_SQR:
 					_vm->_global->_inter_resVal =
 						_vm->_global->_inter_resVal * _vm->_global->_inter_resVal;
 					break;
 
-				case 0:
-				case 1:
-				case 6:
+				case FUNC_SQRT1:
+				case FUNC_SQRT2:
+				case FUNC_SQRT3:
 					curVal = 1;
 					prevVal = 1;
 
@@ -439,33 +439,33 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 					_vm->_global->_inter_resVal = curVal;
 					break;
 
-				case 10:
+				case FUNC_RAND:
 					_vm->_global->_inter_resVal =
 						_vm->_util->getRandom(_vm->_global->_inter_resVal);
 					break;
 
-				case 7:
+				case FUNC_ABS:
 					if (_vm->_global->_inter_resVal < 0)
 						_vm->_global->_inter_resVal = -_vm->_global->_inter_resVal;
 					break;
 				}
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = _vm->_global->_inter_resVal;
 			}
 
-			if ((stkPos > 0) && ((operPtr[-1] == 1) || (operPtr[-1] == 11))) {
+			if ((stkPos > 0) && ((operPtr[-1] == OP_NEG) || (operPtr[-1] == OP_NOT))) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
 
-				if (*operPtr == 1) {
-					*operPtr = 20;
+				if (*operPtr == OP_NEG) {
+					*operPtr = OP_LOAD_IMM_INT16;
 					valPtr[0] = -valPtr[1];
-				} else if (*operPtr == 11) {
-					if (operPtr[1] == 23)
-						*operPtr = 24;
+				} else if (*operPtr == OP_NOT) {
+					if (operPtr[1] == GOB_FALSE)
+						*operPtr = GOB_TRUE;
 					else
-						*operPtr = 23;
+						*operPtr = GOB_FALSE;
 				}
 			}
 
@@ -474,7 +474,7 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 
 			switch (operPtr[-1]) {
 			case 2:
-				if (operPtr[-2] == 22) {
+				if (operPtr[-2] == OP_LOAD_IMM_STR) {
 					if ((char *) decodePtr(valPtr[-2]) != _vm->_global->_inter_resStr) {
 						strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-2]));
 						valPtr[-2] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);
@@ -515,16 +515,16 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 				break;
 			}
 			continue;
-		} // (op >= 19) && (op <= 29)
+		} // (op >= OP_LOAD_IMM_INT32) && (op <= OP_FUNC)
 
-		if ((operation == stopToken) || (operation == 30) ||
-		    (operation == 31) || (operation == 10)) {
+		if ((operation == stopToken) || (operation == OP_OR) ||
+		    (operation == OP_AND) || (operation == OP_END_EXPR)) {
 			while (stkPos >= 2) {
 				var_1A = false;
-				if ((operPtr[-2] == 9) &&
-						((operation == 10) || (operation == stopToken))) {
+				if ((operPtr[-2] == OP_BEGIN_EXPR) &&
+						((operation == OP_END_EXPR) || (operation == stopToken))) {
 					operPtr[-2] = operPtr[-1];
-					if ((operPtr[-2] == 20) || (operPtr[-2] == 22))
+					if ((operPtr[-2] == OP_LOAD_IMM_INT16) || (operPtr[-2] == OP_LOAD_IMM_STR))
 						valPtr[-2] = valPtr[-1];
 
 					stkPos--;
@@ -532,17 +532,17 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 					valPtr--;
 
 					if (stkPos > 1) {
-						if (operPtr[-2] == 1) {
-							operPtr[-2] = 20;
+						if (operPtr[-2] == OP_NEG) {
+							operPtr[-2] = OP_LOAD_IMM_INT16;
 							valPtr[-2] = -valPtr[-1];
 							stkPos--;
 							operPtr--;
 							valPtr--;
-						} else if (operPtr[-2] == 11) {
-							if (operPtr[-1] == 23)
-								operPtr[-2] = 24;
+						} else if (operPtr[-2] == OP_NOT) {
+							if (operPtr[-1] == GOB_FALSE)
+								operPtr[-2] = GOB_TRUE;
 							else
-								operPtr[-2] = 23;
+								operPtr[-2] = GOB_FALSE;
 
 							stkPos--;
 							operPtr--;
@@ -583,21 +583,21 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 
 					if (operation != stopToken)
 						break;
-				}	// if ((operPtr[-2] == 9) && ...)
+				}	// if ((operPtr[-2] == OP_BEGIN_EXPR) && ...)
 
 				for (brackStart = (stkPos - 2); (brackStart > 0) &&
-				    (operStack[brackStart] < 30) && (operStack[brackStart] != 9);
+				    (operStack[brackStart] < OP_OR) && (operStack[brackStart] != OP_BEGIN_EXPR);
 						brackStart--)
 					;
 
-				if ((operStack[brackStart] >= 30) || (operStack[brackStart] == 9))
+				if ((operStack[brackStart] >= OP_OR) || (operStack[brackStart] == OP_BEGIN_EXPR))
 					brackStart++;
 
 				switch (operPtr[-2]) {
 				case OP_ADD:
-					if (operStack[brackStart] == 20) {
+					if (operStack[brackStart] == OP_LOAD_IMM_INT16) {
 						values[brackStart] += valPtr[-1];
-					} else if (operStack[brackStart] == 22) {
+					} else if (operStack[brackStart] == OP_LOAD_IMM_STR) {
 						if ((char *) decodePtr(values[brackStart]) != _vm->_global->_inter_resStr) {
 							strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(values[brackStart]));
 							values[brackStart] =
@@ -652,59 +652,63 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 					valPtr -= 2;
 					break;
 
-				case 30:
-					if (operPtr[-3] == 23)
+				case OP_OR:
+					// (x OR false) == x
+					// (x OR true) == true
+					if (operPtr[-3] == GOB_FALSE)
 						operPtr[-3] = operPtr[-1];
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 31:
-					if (operPtr[-3] == 24)
+				case OP_AND:
+					// (x AND false) == false
+					// (x AND true) == x
+					if (operPtr[-3] == GOB_TRUE)
 						operPtr[-3] = operPtr[-1];
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 32:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) < 0) ? 24 : 23;
+				case OP_LESS:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) < 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 33:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) <= 0) ? 24 : 23;
+				case OP_LEQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) <= 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 34:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) > 0) ? 24 : 23;
+				case OP_GREATER:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) > 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 35:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) >= 0) ? 24 : 23;
+				case OP_GEQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) >= 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 36:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) == 0) ? 24 : 23;
+				case OP_EQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) == 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 37:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) != 0) ? 24 : 23;
+				case OP_NEQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) != 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
@@ -719,17 +723,17 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 					break;
 			}	// while (stkPos >= 2)
 
-			if ((operation == 30) || (operation == 31)) {
-				if (operPtr[-1] == 20) {
+			if ((operation == OP_OR) || (operation == OP_AND)) {
+				if (operPtr[-1] == OP_LOAD_IMM_INT16) {
 					if (valPtr[-1] != 0)
-						operPtr[-1] = 24;
+						operPtr[-1] = GOB_TRUE;
 					else
-						operPtr[-1] = 23;
+						operPtr[-1] = GOB_FALSE;
 				}
 
-				if (((operation == 30) && (operPtr[-1] == 24)) ||
-				    ((operation == 31) && (operPtr[-1] == 23))) {
-					if ((stkPos > 1) && (operPtr[-2] == 9)) {
+				if (((operation == OP_OR) && (operPtr[-1] == GOB_TRUE)) ||
+				    ((operation == OP_AND) && (operPtr[-1] == GOB_FALSE))) {
+					if ((stkPos > 1) && (operPtr[-2] == OP_BEGIN_EXPR)) {
 						skipExpr(10);
 						operPtr[-2] = operPtr[-1];
 						stkPos -= 2;
@@ -739,11 +743,11 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 						skipExpr(stopToken);
 
 					operation = _vm->_global->_inter_execPtr[-1];
-					if ((stkPos > 0) && (operPtr[-1] == 11)) {
-						if (operPtr[0] == 23)
-							operPtr[-1] = 24;
+					if ((stkPos > 0) && (operPtr[-1] == OP_NOT)) {
+						if (operPtr[0] == GOB_FALSE)
+							operPtr[-1] = GOB_TRUE;
 						else
-							operPtr[-1] = 23;
+							operPtr[-1] = GOB_FALSE;
 
 						stkPos--;
 						operPtr--;
@@ -764,16 +768,16 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 				*arg_2 = operStack[0];
 
 			switch (operStack[0]) {
-			case 20:
+			case OP_LOAD_IMM_INT16:
 				_vm->_global->_inter_resVal = values[0];
 				break;
 
-			case 22:
+			case OP_LOAD_IMM_STR:
 				if ((char *) decodePtr(values[0]) != _vm->_global->_inter_resStr)
 					strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(values[0]));
 				break;
 
-			case 11:
+			case OP_NOT:
 				if (arg_2 != 0)
 					*arg_2 ^= 1;
 				break;
@@ -785,21 +789,21 @@ int16 Parse_v1::parseExpr(byte stopToken, byte *arg_2) {
 			default:
 				_vm->_global->_inter_resVal = 0;
 				if (arg_2 != 0)
-					*arg_2 = 20;
+					*arg_2 = OP_LOAD_IMM_INT16;
 				break;
 			}
 			return 0;
-		}		// (operation == stopToken) || (operation == 30) || (operation == 31) || (operation == 10)
+		}		// (operation == stopToken) || (operation == OP_OR) || (operation == OP_AND) || (operation == OP_END_EXPR)
 
-		if (operation < 1 || operation > 11) {
-			if (operation < 32 || operation > 37)
+		if (operation < OP_NEG || operation > OP_NOT) {
+			if (operation < OP_LESS || operation > OP_NEQ)
 				continue;
 
 			if (stkPos > 2) {
 				if (operPtr[-2] == OP_ADD) {
-					if (operPtr[-3] == 20) {
+					if (operPtr[-3] == OP_LOAD_IMM_INT16) {
 						valPtr[-3] += valPtr[-1];
-					} else if (operPtr[-3] == 22) {
+					} else if (operPtr[-3] == OP_LOAD_IMM_STR) {
 						if ((char *) decodePtr(valPtr[-3]) != _vm->_global->_inter_resStr) {
 							strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-3]));
 							valPtr[-3] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);
diff --git a/engines/gob/parse_v2.cpp b/engines/gob/parse_v2.cpp
index 1e06b26b5a..296e135fa1 100644
--- a/engines/gob/parse_v2.cpp
+++ b/engines/gob/parse_v2.cpp
@@ -112,10 +112,10 @@ int16 Parse_v2::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 
 	debugC(5, kDebugParser, "var parse = %d", operation);
 	switch (operation) {
-	case 16:
-	case 26:
-	case 27:
-	case 28:
+	case OP_ARRAY_UINT8:
+	case OP_ARRAY_UINT32:
+	case OP_ARRAY_UINT16:
+	case OP_ARRAY_STR:
 		temp = _vm->_inter->load16();
 		dimCount = *_vm->_global->_inter_execPtr++;
 		arrDesc = _vm->_global->_inter_execPtr;
@@ -125,11 +125,11 @@ int16 Parse_v2::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 			temp2 = parseValExpr(12);
 			offset = arrDesc[dim] * offset + temp2;
 		}
-		if (operation == 16)
+		if (operation == OP_ARRAY_UINT8)
 			return varPos + temp + offset;
-		if (operation == 26)
+		if (operation == OP_ARRAY_UINT32)
 			return varPos + (temp + offset) * 4;
-		if (operation == 27)
+		if (operation == OP_ARRAY_UINT16)
 			return varPos + (temp + offset) * 2;
 		temp *= 4;
 		offset *= 4;
@@ -147,11 +147,11 @@ int16 Parse_v2::parseVarIndex(uint16 *arg_0, uint16 *arg_4) {
 
 	case 23:
 	case 24:
-	case 25:
+	case OP_LOAD_VAR_STR:
 		temp = _vm->_inter->load16() * 4;
 		debugC(5, kDebugParser, "oper = %d",
 				(int16) *_vm->_global->_inter_execPtr);
-		if ((operation == 25) && (*_vm->_global->_inter_execPtr == 13)) {
+		if ((operation == OP_LOAD_VAR_STR) && (*_vm->_global->_inter_execPtr == 13)) {
 			_vm->_global->_inter_execPtr++;
 			val = parseValExpr(12);
 			temp += val;
@@ -237,13 +237,13 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 		operPtr++;
 		valPtr++;
 
-		if ((operation >= 16) && (operation <= 29)) {
-			*operPtr = 20;
+		if ((operation >= OP_ARRAY_UINT8) && (operation <= OP_FUNC)) {
+			*operPtr = OP_LOAD_IMM_INT16;
 			switch (operation) {
-			case 16:
-			case 26:
-			case 27:
-			case 28:
+			case OP_ARRAY_UINT8:
+			case OP_ARRAY_UINT32:
+			case OP_ARRAY_UINT16:
+			case OP_ARRAY_STR:
 				temp = _vm->_inter->load16();
 				dimCount = *_vm->_global->_inter_execPtr++;
 				arrDesc = _vm->_global->_inter_execPtr;
@@ -253,13 +253,13 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 					temp2 = parseValExpr(12);
 					offset = arrDesc[dim] * offset + temp2;
 				}
-				if (operation == 16)
+				if (operation == OP_ARRAY_UINT8)
 					*valPtr = (int8) READ_VARO_UINT8(varPos + temp + offset);
-				else if (operation == 26)
+				else if (operation == OP_ARRAY_UINT32)
 					*valPtr = (uint16) READ_VARO_UINT32(varPos + temp * 4 + offset * 4);
-				else if (operation == 27)
+				else if (operation == OP_ARRAY_UINT16)
 					*valPtr = READ_VARO_UINT16(varPos + temp * 2 + offset * 2);
-				else if (operation == 28) {
+				else if (operation == OP_ARRAY_STR) {
 					_vm->_global->_inter_execPtr++;
 					temp2 = parseValExpr(12);
 					*valPtr = READ_VARO_UINT8(varPos + temp * 4 +
@@ -275,16 +275,16 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 				*valPtr = (int8) READ_VARO_UINT8(varPos + _vm->_inter->load16());
 				break;
 
-			case 19:
+			case OP_LOAD_IMM_INT32:
 				*valPtr = (uint16) READ_LE_UINT32(varPos + _vm->_global->_inter_execPtr);
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 20:
+			case OP_LOAD_IMM_INT16:
 				*valPtr = _vm->_inter->load16();
 				break;
 
-			case 21:
+			case OP_LOAD_IMM_INT8:
 				*valPtr = (int8) *_vm->_global->_inter_execPtr++;
 				break;
 
@@ -296,24 +296,24 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 				*valPtr = READ_VARO_UINT16(varPos + _vm->_inter->load16() * 4);
 				break;
 
-			case 25:
+			case OP_LOAD_VAR_STR:
 				temp = _vm->_inter->load16() * 4;
 				_vm->_global->_inter_execPtr++;
 				temp += parseValExpr(12);
 				*valPtr = READ_VARO_UINT8(varPos + temp);
 				break;
 
-			case 29:
+			case OP_FUNC:
 				operation = *_vm->_global->_inter_execPtr++;
 				parseExpr(10, 0);
 
-				if (operation == 5) {
+				if (operation == FUNC_SQR) {
 					_vm->_global->_inter_resVal =
 						_vm->_global->_inter_resVal * _vm->_global->_inter_resVal;
-				} else if (operation == 7) {
+				} else if (operation == FUNC_ABS) {
 					if (_vm->_global->_inter_resVal < 0)
 						_vm->_global->_inter_resVal = -_vm->_global->_inter_resVal;
-				} else if (operation == 10) {
+				} else if (operation == FUNC_RAND) {
 					_vm->_global->_inter_resVal =
 						_vm->_util->getRandom(_vm->_global->_inter_resVal);
 				}
@@ -321,15 +321,15 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 				break;
 
 			}	// switch
-			if ((stkPos > 0) && (operPtr[-1] == 1)) {
+			if ((stkPos > 0) && (operPtr[-1] == OP_NEG)) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
-				operPtr[0] = 20;
+				operPtr[0] = OP_LOAD_IMM_INT16;
 				valPtr[0] = -valPtr[1];
 			}
 
-			if ((stkPos > 0) && (operPtr[-1] > 4) && (operPtr[-1] < 9)) {
+			if ((stkPos > 0) && (operPtr[-1] >= OP_MUL) && (operPtr[-1] <= OP_BITAND)) {
 				stkPos -= 2;
 				operPtr -= 2;
 				valPtr -= 2;
@@ -351,26 +351,26 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 					valPtr[0] &= valPtr[2];
 					break;
 				}
-			}	// if ((stkPos > 0) && (cmdPtr[-1] > 4) && (cmdPtr[-1] < 9))
+			}	// if ((stkPos > 0) && (cmdPtr[-1] >= OP_MUL) && (cmdPtr[-1] <= OP_BITAND))
 			varPos = 0;
 			continue;
 		}
 
-		if ((operation >= 1) && (operation <= 9)) {
+		if ((operation >= OP_NEG) && (operation <= OP_BEGIN_EXPR)) {
 			*operPtr = operation;
 			continue;
 		}
 
 		while (stkPos >= 2) {
-			if (operPtr[-2] == 9) {
+			if (operPtr[-2] == OP_BEGIN_EXPR) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
 
 				operPtr[-1] = operPtr[0];
 				valPtr[-1] = valPtr[0];
-				if ((stkPos > 1) && (operPtr[-2] == 1)) {
-					operPtr[-2] = 20;
+				if ((stkPos > 1) && (operPtr[-2] == OP_NEG)) {
+					operPtr[-2] = OP_LOAD_IMM_INT16;
 					valPtr[-2] = -valPtr[-1];
 
 					stkPos--;
@@ -378,7 +378,7 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 					valPtr--;
 				}
 
-				if ((stkPos > 2) && (operPtr[-2] > 4) && (operPtr[-2] < 9)) {
+				if ((stkPos > 2) && (operPtr[-2] >= OP_MUL) && (operPtr[-2] <= OP_BITAND)) {
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
@@ -400,16 +400,16 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 						break;
 					}
 				}
-				if (operation == 10)
+				if (operation == OP_END_EXPR)
 					break;
-			}	// operPtr[-2] == 9
+			}	// operPtr[-2] == OP_BEGIN_EXPR
 
 			for (brackPos = (stkPos - 2); (brackPos > 0) &&
-			    (operStack[brackPos] < 30) && (operStack[brackPos] != 9);
+			    (operStack[brackPos] < OP_OR) && (operStack[brackPos] != OP_BEGIN_EXPR);
 					brackPos--)
 				;
 
-			if ((operStack[brackPos] >= 30) || (operStack[brackPos] == 9))
+			if ((operStack[brackPos] >= OP_OR) || (operStack[brackPos] == OP_BEGIN_EXPR))
 				brackPos++;
 
 			if ((operPtr[-2] < 2) || (operPtr[-2] > 8))
@@ -443,7 +443,7 @@ int16 Parse_v2::parseValExpr(byte stopToken) {
 			}
 		}
 
-		if (operation != 10) {
+		if (operation != OP_END_EXPR) {
 			if (operation != stopToken) {
 				debugC(5, kDebugParser, "stoptoken error: %d != %d",
 						operation, stopToken);
@@ -484,7 +484,7 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 	operPtr = operStack - 1;
 	valPtr = values - 1;
 
-	while (1) {
+	while (true) {
 		operation = *_vm->_global->_inter_execPtr++;
 
 		while ((operation == 14) || (operation == 15)) {
@@ -530,13 +530,13 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 		operPtr++;
 		valPtr++;
 
-		if ((operation >= 16) && (operation <= 29)) {
+		if ((operation >= OP_ARRAY_UINT8) && (operation <= OP_FUNC)) {
 			switch (operation) {
-			case 16:
-			case 26:
-			case 27:
-			case 28:
-				*operPtr = (operation == 28) ? 22 : 20;
+			case OP_ARRAY_UINT8:
+			case OP_ARRAY_UINT32:
+			case OP_ARRAY_UINT16:
+			case OP_ARRAY_STR:
+				*operPtr = (operation == OP_ARRAY_STR) ? OP_LOAD_IMM_STR : OP_LOAD_IMM_INT16;
 				temp = _vm->_inter->load16();
 				dimCount = *_vm->_global->_inter_execPtr++;
 				arrDescPtr = _vm->_global->_inter_execPtr;
@@ -546,20 +546,20 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 					temp2 = parseValExpr(12);
 					offset = offset * arrDescPtr[dim] + temp2;
 				}
-				if (operation == 16)
+				if (operation == OP_ARRAY_UINT8)
 					*valPtr = (int8) READ_VARO_UINT8(varPos + temp + offset);
-				else if (operation == 26)
+				else if (operation == OP_ARRAY_UINT32)
 					*valPtr = READ_VARO_UINT32(varPos + temp * 4 + offset * 4);
-				else if (operation == 27)
+				else if (operation == OP_ARRAY_UINT16)
 					*valPtr = (int16) READ_VARO_UINT16(varPos + temp * 2 + offset * 2);
-				else if (operation == 28) {
+				else if (operation == OP_ARRAY_STR) {
 					*valPtr = encodePtr(_vm->_inter->_variables->getAddressOff8(
 								varPos + temp * 4 + offset * _vm->_global->_inter_animDataSize * 4, 0),
 							kInterVar);
 					if (*_vm->_global->_inter_execPtr == 13) {
 						_vm->_global->_inter_execPtr++;
 						temp2 = parseValExpr(12);
-						*operPtr = 20;
+						*operPtr = OP_LOAD_IMM_INT16;
 						*valPtr = READ_VARO_UINT8(varPos + temp * 4 +
 								offset * 4 * _vm->_global->_inter_animDataSize + temp2);
 					}
@@ -567,68 +567,68 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 				break;
 
 			case 17:
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = (int16) READ_VARO_UINT16(varPos + _vm->_inter->load16() * 2);
 				break;
 
 			case 18:
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = (int8) READ_VARO_UINT8(varPos + _vm->_inter->load16());
 				break;
 
-			case 19:
-				*operPtr = 20;
+			case OP_LOAD_IMM_INT32:
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = READ_LE_UINT32(varPos + _vm->_global->_inter_execPtr);
 				_vm->_global->_inter_execPtr += 4;
 				break;
 
-			case 20:
-				*operPtr = 20;
+			case OP_LOAD_IMM_INT16:
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = _vm->_inter->load16();
 				break;
 
-			case 21:
-				*operPtr = 20;
+			case OP_LOAD_IMM_INT8:
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = (int8) *_vm->_global->_inter_execPtr++;
 				break;
 
-			case 22:
-				*operPtr = 22;
+			case OP_LOAD_IMM_STR:
+				*operPtr = OP_LOAD_IMM_STR;
 				*valPtr = encodePtr(_vm->_global->_inter_execPtr, kExecPtr);
 				_vm->_global->_inter_execPtr +=
 					strlen((char *) _vm->_global->_inter_execPtr) + 1;
 				break;
 
 			case 23:
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = READ_VARO_UINT32(varPos + _vm->_inter->load16() * 4);
 				break;
 
 			case 24:
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = (int16) READ_VARO_UINT16(varPos + _vm->_inter->load16() * 4);
 				break;
 
-			case 25:
-				*operPtr = 22;
+			case OP_LOAD_VAR_STR:
+				*operPtr = OP_LOAD_IMM_STR;
 				temp = _vm->_inter->load16() * 4;
 				*valPtr = encodePtr(_vm->_inter->_variables->getAddressOff8(varPos + temp, 0), kInterVar);
 				if (*_vm->_global->_inter_execPtr == 13) {
 					_vm->_global->_inter_execPtr++;
 					temp += parseValExpr(12);
-					*operPtr = 20;
+					*operPtr = OP_LOAD_IMM_INT16;
 					*valPtr = READ_VARO_UINT8(varPos + temp);
 				}
 				break;
 
-			case 29:
+			case OP_FUNC:
 				operation = *_vm->_global->_inter_execPtr++;
 				parseExpr(10, 0);
 
 				switch (operation) {
-				case 0:
-				case 1:
-				case 6:
+				case FUNC_SQRT1:
+				case FUNC_SQRT2:
+				case FUNC_SQRT3:
 					curVal = 1;
 					prevVal = 1;
 
@@ -640,37 +640,37 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 					_vm->_global->_inter_resVal = curVal;
 					break;
 
-				case 5:
+				case FUNC_SQR:
 					_vm->_global->_inter_resVal =
 						_vm->_global->_inter_resVal * _vm->_global->_inter_resVal;
 					break;
 
-				case 7:
+				case FUNC_ABS:
 					if (_vm->_global->_inter_resVal < 0)
 						_vm->_global->_inter_resVal = -_vm->_global->_inter_resVal;
 					break;
 
-				case 10:
+				case FUNC_RAND:
 					_vm->_global->_inter_resVal =
 						_vm->_util->getRandom(_vm->_global->_inter_resVal);
 					break;
 				}
 
-				*operPtr = 20;
+				*operPtr = OP_LOAD_IMM_INT16;
 				*valPtr = _vm->_global->_inter_resVal;
 				break;
 			}
 
-			if ((stkPos > 0) && ((operPtr[-1] == 1) || (operPtr[-1] == 11))) {
+			if ((stkPos > 0) && ((operPtr[-1] == OP_NEG) || (operPtr[-1] == OP_NOT))) {
 				stkPos--;
 				operPtr--;
 				valPtr--;
 
-				if (*operPtr == 1) {
-					*operPtr = 20;
+				if (*operPtr == OP_NEG) {
+					*operPtr = OP_LOAD_IMM_INT16;
 					valPtr[0] = -valPtr[1];
 				} else
-					*operPtr = (operPtr[1] == 23) ? 24 : 23;
+					*operPtr = (operPtr[1] == GOB_FALSE) ? GOB_TRUE : GOB_FALSE;
 			}
 
 			if (stkPos <= 0) {
@@ -679,8 +679,8 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 			}
 
 			switch (operPtr[-1]) {
-			case 2:
-				if (operPtr[-2] == 22) {
+			case OP_ADD:
+				if (operPtr[-2] == OP_LOAD_IMM_STR) {
 					if ((char *) decodePtr(valPtr[-2]) != _vm->_global->_inter_resStr) {
 						strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-2]));
 						valPtr[-2] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);
@@ -722,16 +722,16 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 			}
 			varPos = 0;
 			continue;
-		} // (op >= 16) && (op <= 29)
+		} // (op >= OP_ARRAY_UINT8) && (op <= OP_FUNC)
 
-		if ((operation == stopToken) || (operation == 30) ||
-				(operation == 31) || (operation == 10)) {
+		if ((operation == stopToken) || (operation == OP_OR) ||
+				(operation == OP_AND) || (operation == OP_END_EXPR)) {
 			while (stkPos >= 2) {
 				var_1A = false;
-				if ((operPtr[-2] == 9) &&
-						((operation == 10) || (operation == stopToken))) {
+				if ((operPtr[-2] == OP_BEGIN_EXPR) &&
+						((operation == OP_END_EXPR) || (operation == stopToken))) {
 					operPtr[-2] = operPtr[-1];
-					if ((operPtr[-2] == 20) || (operPtr[-2] == 22))
+					if ((operPtr[-2] == OP_LOAD_IMM_INT16) || (operPtr[-2] == OP_LOAD_IMM_STR))
 						valPtr[-2] = valPtr[-1];
 
 					stkPos--;
@@ -739,14 +739,14 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 					valPtr--;
 
 					if (stkPos > 1) {
-						if (operPtr[-2] == 1) {
-							operPtr[-2] = 20;
+						if (operPtr[-2] == OP_NEG) {
+							operPtr[-2] = OP_LOAD_IMM_INT16;
 							valPtr[-2] = -valPtr[-1];
 							stkPos--;
 							operPtr--;
 							valPtr--;
-						} else if (operPtr[-2] == 11) {
-							operPtr[-2] = (operPtr[-1] == 23) ? 24 : 23;
+						} else if (operPtr[-2] == OP_NOT) {
+							operPtr[-2] = (operPtr[-1] == GOB_FALSE) ? GOB_TRUE : GOB_FALSE;
 							stkPos--;
 							operPtr--;
 							valPtr--;
@@ -787,23 +787,23 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 
 					if (operation != stopToken)
 						break;
-				}	// if ((operPtr[-2] == 9) && ...)
+				}	// if ((operPtr[-2] == OP_BEGIN_EXPR) && ...)
 
 				for (brackStart = (stkPos - 2); (brackStart > 0) &&
-				    (operStack[brackStart] < 30) && (operStack[brackStart] != 9);
+				    (operStack[brackStart] < OP_OR) && (operStack[brackStart] != OP_BEGIN_EXPR);
 						brackStart--)
 					;
 
-				if ((operStack[brackStart] >= 30) || (operStack[brackStart] == 9))
+				if ((operStack[brackStart] >= OP_OR) || (operStack[brackStart] == OP_BEGIN_EXPR))
 					brackStart++;
 
 				int cmpTemp;
 
 				switch (operPtr[-2]) {
 				case OP_ADD:
-					if (operStack[brackStart] == 20) {
+					if (operStack[brackStart] == OP_LOAD_IMM_INT16) {
 						values[brackStart] += valPtr[-1];
-					} else if (operStack[brackStart] == 22) {
+					} else if (operStack[brackStart] == OP_LOAD_IMM_STR) {
 						if ((char *) decodePtr(values[brackStart]) != _vm->_global->_inter_resStr) {
 							strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(values[brackStart]));
 							values[brackStart] =
@@ -858,61 +858,65 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 					valPtr -= 2;
 					break;
 
-				case 30:
-					if (operPtr[-3] == 23)
+				case OP_OR:
+					// (x OR false) == x
+					// (x OR true) == true
+					if (operPtr[-3] == GOB_FALSE)
 						operPtr[-3] = operPtr[-1];
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 31:
-					if (operPtr[-3] == 24)
+				case OP_AND:
+					// (x AND false) == false
+					// (x AND true) == x
+					if (operPtr[-3] == GOB_TRUE)
 						operPtr[-3] = operPtr[-1];
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 32:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) < 0) ? 24 : 23;
+				case OP_LESS:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) < 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 33:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) <= 0) ? 24 : 23;
+				case OP_LEQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) <= 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 34:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) > 0) ? 24 : 23;
+				case OP_GREATER:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) > 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 35:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) >= 0) ? 24 : 23;
+				case OP_GEQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) >= 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 36:
-					operPtr[-3] = (cmpHelper(operPtr, valPtr) == 0) ? 24 : 23;
+				case OP_EQ:
+					operPtr[-3] = (cmpHelper(operPtr, valPtr) == 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
 					break;
 
-				case 37:
-					if (operPtr[-3] == 20) {
+				case OP_NEQ:
+					if (operPtr[-3] == OP_LOAD_IMM_INT16) {
 						cmpTemp = valPtr[-3] - valPtr[-1];
-					} else if (operPtr[-3] == 22) {
+					} else if (operPtr[-3] == OP_LOAD_IMM_STR) {
 						if ((char *) decodePtr(valPtr[-3]) != _vm->_global->_inter_resStr) {
 							strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-3]));
 							valPtr[-3] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);
@@ -920,8 +924,8 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 						// FIXME: Why scumm_stricmp here and strcmp everywhere else?
 						cmpTemp = scumm_stricmp(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-1]));
 					}
-					operPtr[-3] = (cmpTemp != 0) ? 24 : 23;
-					//operPtr[-3] = (cmpHelper(operPtr, valPtr) != 0) ? 24 : 23;
+					operPtr[-3] = (cmpTemp != 0) ? GOB_TRUE : GOB_FALSE;
+					//operPtr[-3] = (cmpHelper(operPtr, valPtr) != 0) ? GOB_TRUE : GOB_FALSE;
 					stkPos -= 2;
 					operPtr -= 2;
 					valPtr -= 2;
@@ -936,17 +940,17 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 					break;
 			}	// while (stkPos >= 2)
 
-			if ((operation == 30) || (operation == 31)) {
-				if (operPtr[-1] == 20) {
+			if ((operation == OP_OR) || (operation == OP_AND)) {
+				if (operPtr[-1] == OP_LOAD_IMM_INT16) {
 					if (valPtr[-1] != 0)
-						operPtr[-1] = 24;
+						operPtr[-1] = GOB_TRUE;
 					else
-						operPtr[-1] = 23;
+						operPtr[-1] = GOB_FALSE;
 				}
 
-				if (((operation == 30) && (operPtr[-1] == 24)) ||
-				    ((operation == 31) && (operPtr[-1] == 23))) {
-					if ((stkPos > 1) && (operPtr[-2] == 9)) {
+				if (((operation == OP_OR) && (operPtr[-1] == GOB_TRUE)) ||
+				    ((operation == OP_AND) && (operPtr[-1] == GOB_FALSE))) {
+					if ((stkPos > 1) && (operPtr[-2] == OP_BEGIN_EXPR)) {
 						skipExpr(10);
 						operPtr[-2] = operPtr[-1];
 						stkPos -= 2;
@@ -956,11 +960,11 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 						skipExpr(stopToken);
 					}
 					operation = _vm->_global->_inter_execPtr[-1];
-					if ((stkPos > 0) && (operPtr[-1] == 11)) {
-						if (operPtr[0] == 23)
-							operPtr[-1] = 24;
+					if ((stkPos > 0) && (operPtr[-1] == OP_NOT)) {
+						if (operPtr[0] == GOB_FALSE)
+							operPtr[-1] = GOB_TRUE;
 						else
-							operPtr[-1] = 23;
+							operPtr[-1] = GOB_FALSE;
 
 						stkPos--;
 						operPtr--;
@@ -981,16 +985,16 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 				*arg_2 = operStack[0];
 
 			switch (operStack[0]) {
-			case 11:
+			case OP_NOT:
 				if (arg_2 != 0)
 					*arg_2 ^= 1;
 				break;
 
-			case 20:
+			case OP_LOAD_IMM_INT16:
 				_vm->_global->_inter_resVal = values[0];
 				break;
 
-			case 22:
+			case OP_LOAD_IMM_STR:
 				if ((char *) decodePtr(values[0]) != _vm->_global->_inter_resStr)
 					strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(values[0]));
 				break;
@@ -1002,21 +1006,21 @@ int16 Parse_v2::parseExpr(byte stopToken, byte *arg_2) {
 			default:
 				_vm->_global->_inter_resVal = 0;
 				if (arg_2 != 0)
-					*arg_2 = 20;
+					*arg_2 = OP_LOAD_IMM_INT16;
 				break;
 			}
 			return 0;
-		}		// (operation == stopToken) || (operation == 30) || (operation == 31) || (operation == 10)
+		}		// (operation == stopToken) || (operation == OP_OR) || (operation == OP_AND) || (operation == OP_END_EXPR)
 
-		if ((operation < 1) || (operation > 11)) {
-			if ((operation < 32) || (operation > 37))
+		if ((operation < OP_NEG) || (operation > OP_NOT)) {
+			if ((operation < OP_LESS) || (operation > OP_NEQ))
 				continue;
 
 			if (stkPos > 2) {
 				if (operPtr[-2] == OP_ADD) {
-					if (operPtr[-3] == 20) {
+					if (operPtr[-3] == OP_LOAD_IMM_INT16) {
 						valPtr[-3] += valPtr[-1];
-					} else if (operPtr[-3] == 22) {
+					} else if (operPtr[-3] == OP_LOAD_IMM_STR) {
 						if ((char *) decodePtr(valPtr[-3]) != _vm->_global->_inter_resStr) {
 							strcpy(_vm->_global->_inter_resStr, (char *) decodePtr(valPtr[-3]));
 							valPtr[-3] = encodePtr((byte *) _vm->_global->_inter_resStr, kResStr);