SCI: Renamed execution_stack -> _executionStack and turned it into a Common::Array

svn-id: r40182

8 files changed, 91 insertions, 108 deletions

diff --git a/engines/sci/engine/game.cpp b/engines/sci/engine/game.cpp
index 48e70eb801..0130ee7afe 100644
--- a/engines/sci/engine/game.cpp
+++ b/engines/sci/engine/game.cpp
@@ -444,7 +444,7 @@ int script_init_engine(EngineState *s, sci_version_t version) {
 	s->r_acc = s->r_prev = NULL_REG;
 	s->r_amp_rest = 0;
 
-	s->execution_stack = NULL;    // Start without any execution stack
+	s->_executionStack.clear();    // Start without any execution stack
 	s->execution_stack_base = -1; // No vm is running yet
 	s->execution_stack_pos = -1;   // Start at execution stack position 0
 
@@ -620,7 +620,7 @@ int game_init(EngineState *s) {
 }
 
 int game_exit(EngineState *s) {
-	free(s->execution_stack);
+	s->_executionStack.clear();
 
 	if (!s->successor) {
 		sfx_exit(&s->sound);
diff --git a/engines/sci/engine/gc.cpp b/engines/sci/engine/gc.cpp
index ae0b9fefed..c3fcfff75f 100644
--- a/engines/sci/engine/gc.cpp
+++ b/engines/sci/engine/gc.cpp
@@ -153,10 +153,10 @@ reg_t_hash_map *find_all_used_references(EngineState *s) {
 	// Init: Value Stack
 	// We do this one by hand since the stack doesn't know the current execution stack
 	{
-		ExecStack *xs = s->execution_stack + s->execution_stack_pos;
+		ExecStack &xs = s->_executionStack[s->execution_stack_pos];
 		reg_t *pos;
 
-		for (pos = s->stack_base; pos < xs->sp; pos++)
+		for (pos = s->stack_base; pos < xs.sp; pos++)
 			worklist_push(&worklist, nonnormal_map, *pos);
 	}
 #ifdef DEBUG_GC_VERBOSE
@@ -165,13 +165,13 @@ reg_t_hash_map *find_all_used_references(EngineState *s) {
 
 	// Init: Execution Stack
 	for (i = 0; i <= s->execution_stack_pos; i++) {
-		ExecStack *es = s->execution_stack + i;
+		ExecStack &es = s->_executionStack[i];
 
-		if (es->type != EXEC_STACK_TYPE_KERNEL) {
-			worklist_push(&worklist, nonnormal_map, es->objp);
-			worklist_push(&worklist, nonnormal_map, es->sendp);
-			if (es->type == EXEC_STACK_TYPE_VARSELECTOR)
-				worklist_push(&worklist, nonnormal_map, *(es->addr.varp));
+		if (es.type != EXEC_STACK_TYPE_KERNEL) {
+			worklist_push(&worklist, nonnormal_map, es.objp);
+			worklist_push(&worklist, nonnormal_map, es.sendp);
+			if (es.type == EXEC_STACK_TYPE_VARSELECTOR)
+				worklist_push(&worklist, nonnormal_map, *(es.addr.varp));
 		}
 	}
 #ifdef DEBUG_GC_VERBOSE
diff --git a/engines/sci/engine/kscripts.cpp b/engines/sci/engine/kscripts.cpp
index df40781c95..9559c792c9 100644
--- a/engines/sci/engine/kscripts.cpp
+++ b/engines/sci/engine/kscripts.cpp
@@ -271,12 +271,12 @@ reg_t kDisposeScript(EngineState *s, int funct_nr, int argc, reg_t *argv) {
 	if (s->seg_manager->scriptIsLoaded(script, SCRIPT_ID)) {
 		int id = s->seg_manager->segGet(script);
 
-		if (s->execution_stack[s->execution_stack_pos].addr.pc.segment != id)
+		if (s->_executionStack[s->execution_stack_pos].addr.pc.segment != id)
 			s->seg_manager->setLockers(1, script, SCRIPT_ID);
 	}
 
 	script_uninstantiate(s, script);
-	s->execution_stack_pos_changed = 1;
+	s->_executionStackPosChanged = true;
 	return s->r_acc;
 }
 
diff --git a/engines/sci/engine/scriptconsole.cpp b/engines/sci/engine/scriptconsole.cpp
index b6f09ce8bc..decfd167dc 100644
--- a/engines/sci/engine/scriptconsole.cpp
+++ b/engines/sci/engine/scriptconsole.cpp
@@ -227,10 +227,10 @@ int parse_reg_t(EngineState *s, const char *str, reg_t *dest) { // Returns 0 on
 		rel_offsetting = 1;
 
 		if (!scumm_strnicmp(str + 1, "PC", 2)) {
-			*dest = s->execution_stack[s->execution_stack_pos].addr.pc;
+			*dest = s->_executionStack[s->execution_stack_pos].addr.pc;
 			offsetting = str + 3;
 		} else if (!scumm_strnicmp(str + 1, "P", 1)) {
-			*dest = s->execution_stack[s->execution_stack_pos].addr.pc;
+			*dest = s->_executionStack[s->execution_stack_pos].addr.pc;
 			offsetting = str + 2;
 		} else if (!scumm_strnicmp(str + 1, "PREV", 4)) {
 			*dest = s->r_prev;
@@ -242,10 +242,10 @@ int parse_reg_t(EngineState *s, const char *str, reg_t *dest) { // Returns 0 on
 			*dest = s->r_acc;
 			offsetting = str + 2;
 		} else if (!scumm_strnicmp(str + 1, "OBJ", 3)) {
-			*dest = s->execution_stack[s->execution_stack_pos].objp;
+			*dest = s->_executionStack[s->execution_stack_pos].objp;
 			offsetting = str + 4;
 		} else if (!scumm_strnicmp(str + 1, "O", 1)) {
-			*dest = s->execution_stack[s->execution_stack_pos].objp;
+			*dest = s->_executionStack[s->execution_stack_pos].objp;
 			offsetting = str + 2;
 		} else
 			return 1; // No matching register
diff --git a/engines/sci/engine/scriptdebug.cpp b/engines/sci/engine/scriptdebug.cpp
index 27c41795ec..76ac53ec81 100644
--- a/engines/sci/engine/scriptdebug.cpp
+++ b/engines/sci/engine/scriptdebug.cpp
@@ -693,21 +693,16 @@ int c_seginfo(EngineState *s) {
 }
 
 int c_debuginfo(EngineState *s) {
-	ExecStack *eframe = NULL;
-
 	if (!_debugstate_valid) {
 		sciprintf("Not in debug state\n");
 		return 1;
 	}
 
-	if (s->execution_stack && s->execution_stack_pos >= 0)
-		eframe = s->execution_stack + s->execution_stack_pos;
-
 	sciprintf("acc="PREG" prev="PREG" &rest=%x\n", PRINT_REG(s->r_acc), PRINT_REG(s->r_prev), *p_restadjust);
 
-	if (eframe)
+	if (!s->_executionStack.empty() && s->execution_stack_pos >= 0) {
 		sciprintf("pc="PREG" obj="PREG" fp="PSTK" sp="PSTK"\n", PRINT_REG(*p_pc), PRINT_REG(*p_objp), PRINT_STK(*p_pp), PRINT_STK(*p_sp));
-	else
+	} else
 		sciprintf("<no execution stack: pc,obj,fp omitted>\n");
 
 	return 0;
@@ -1155,26 +1150,23 @@ int c_restart_game(EngineState *s) {
 }
 
 int c_stack(EngineState *s) {
-	int i;
-	ExecStack *xs;
-
 	if (!s) {
 		sciprintf("Not in debug state\n");
 		return 1;
 	}
 
-	if (s->execution_stack_pos >= 0)
-		xs = s->execution_stack + s->execution_stack_pos;
-	else {
+	if (s->execution_stack_pos < 0) {
 		sciprintf("No exec stack!");
 		return 1;
 	}
 
-	for (i = cmd_params[0].val ; i > 0; i--) {
-		if ((xs->sp - xs->fp - i) == 0)
+	ExecStack &xs = s->_executionStack[s->execution_stack_pos];
+
+	for (int i = cmd_params[0].val ; i > 0; i--) {
+		if ((xs.sp - xs.fp - i) == 0)
 			sciprintf("-- temp variables --\n");
-		if (xs->sp - i >= s->stack_base)
-			sciprintf(PSTK" = "PREG"\n", PRINT_STK(xs->sp - i), PRINT_REG(xs->sp[-i]));
+		if (xs.sp - i >= s->stack_base)
+			sciprintf(PSTK" = "PREG"\n", PRINT_STK(xs.sp - i), PRINT_REG(xs.sp[-i]));
 	}
 
 	return 0;
@@ -1547,58 +1539,58 @@ static int c_backtrace(EngineState *s) {
 
 	sciprintf("Call stack (current base: 0x%x):\n", s->execution_stack_base);
 	for (i = 0; i <= s->execution_stack_pos; i++) {
-		ExecStack *call = &(s->execution_stack[i]);
-		const char *objname = obj_get_name(s, call->sendp);
+		ExecStack &call = s->_executionStack[i];
+		const char *objname = obj_get_name(s, call.sendp);
 		int paramc, totalparamc;
 
-		switch (call->type) {
+		switch (call.type) {
 
 		case EXEC_STACK_TYPE_CALL: {// Normal function
-			sciprintf(" %x:[%x]  %s::%s(", i, call->origin, objname, (call->selector == -1) ? "<call[be]?>" :
-			          selector_name(s, call->selector));
+			sciprintf(" %x:[%x]  %s::%s(", i, call.origin, objname, (call.selector == -1) ? "<call[be]?>" :
+			          selector_name(s, call.selector));
 		}
 		break;
 
 		case EXEC_STACK_TYPE_KERNEL: // Kernel function
-			sciprintf(" %x:[%x]  k%s(", i, call->origin, s->_kernelNames[-(call->selector)-42].c_str());
+			sciprintf(" %x:[%x]  k%s(", i, call.origin, s->_kernelNames[-(call.selector)-42].c_str());
 			break;
 
 		case EXEC_STACK_TYPE_VARSELECTOR:
-			sciprintf(" %x:[%x] vs%s %s::%s (", i, call->origin, (call->argc) ? "write" : "read",
-			          objname, s->_selectorNames[call->selector].c_str());
+			sciprintf(" %x:[%x] vs%s %s::%s (", i, call.origin, (call.argc) ? "write" : "read",
+			          objname, s->_selectorNames[call.selector].c_str());
 			break;
 		}
 
-		totalparamc = call->argc;
+		totalparamc = call.argc;
 
 		if (totalparamc > 16)
 			totalparamc = 16;
 
 		for (paramc = 1; paramc <= totalparamc; paramc++) {
-			sciprintf(PREG, PRINT_REG(call->variables_argp[paramc]));
+			sciprintf(PREG, PRINT_REG(call.variables_argp[paramc]));
 
-			if (paramc < call->argc)
+			if (paramc < call.argc)
 				sciprintf(", ");
 		}
 
-		if (call->argc > 16)
+		if (call.argc > 16)
 			sciprintf("...");
 
-		sciprintf(")\n    obj@"PREG, PRINT_REG(call->objp));
-		if (call->type == EXEC_STACK_TYPE_CALL) {
-			sciprintf(" pc="PREG, PRINT_REG(call->addr.pc));
-			if (call->sp == CALL_SP_CARRY)
+		sciprintf(")\n    obj@"PREG, PRINT_REG(call.objp));
+		if (call.type == EXEC_STACK_TYPE_CALL) {
+			sciprintf(" pc="PREG, PRINT_REG(call.addr.pc));
+			if (call.sp == CALL_SP_CARRY)
 				sciprintf(" sp,fp:carry");
 			else {
-				sciprintf(" sp="PSTK, PRINT_STK(call->sp));
-				sciprintf(" fp="PSTK, PRINT_STK(call->fp));
+				sciprintf(" sp="PSTK, PRINT_STK(call.sp));
+				sciprintf(" fp="PSTK, PRINT_STK(call.fp));
 			}
 		} else
 			sciprintf(" pc:none");
 
-		sciprintf(" argp:"PSTK, PRINT_STK(call->variables_argp));
-		if (call->type == EXEC_STACK_TYPE_CALL)
-			sciprintf(" script: %d", s->seg_manager->heap[call->addr.pc.segment]->data.script.nr);
+		sciprintf(" argp:"PSTK, PRINT_STK(call.variables_argp));
+		if (call.type == EXEC_STACK_TYPE_CALL)
+			sciprintf(" script: %d", s->seg_manager->heap[call.addr.pc.segment]->data.script.nr);
 		sciprintf("\n");
 	}
 
@@ -2153,7 +2145,7 @@ static int c_set_acc(EngineState *s) {
 static int c_send(EngineState *s) {
 	reg_t object = cmd_params[0].reg;
 	char *selector_name = cmd_params[1].str;
-	StackPtr stackframe = s->execution_stack->sp;
+	StackPtr stackframe = s->_executionStack[0].sp;
 	int selector_id;
 	unsigned int i;
 	ExecStack *xstack;
@@ -2187,8 +2179,8 @@ static int c_send(EngineState *s) {
 	for (i = 2; i < cmd_paramlength; i++)
 		stackframe[i] = cmd_params[i].reg;
 
-	xstack = add_exec_stack_entry(s, fptr, s->execution_stack->sp + cmd_paramlength, object, cmd_paramlength - 2,
-									s->execution_stack->sp - 1, 0, object, s->execution_stack_pos, SCI_XS_CALLEE_LOCALS);
+	xstack = add_exec_stack_entry(s, fptr, s->_executionStack[0].sp + cmd_paramlength, object, cmd_paramlength - 2,
+									s->_executionStack[0].sp - 1, 0, object, s->execution_stack_pos, SCI_XS_CALLEE_LOCALS);
 	xstack->selector = selector_id;
 	xstack->type = selector_type == kSelectorVariable ? EXEC_STACK_TYPE_VARSELECTOR : EXEC_STACK_TYPE_CALL;
 
@@ -2198,7 +2190,7 @@ static int c_send(EngineState *s) {
 	xstack->sp += cmd_paramlength;
 	xstack->fp += cmd_paramlength;
 
-	s->execution_stack_pos_changed = 1;
+	s->_executionStackPosChanged = true;
 
 	return 0;
 }
@@ -2934,7 +2926,7 @@ void script_debug(EngineState *s, reg_t *pc, StackPtr *sp, StackPtr *pp, reg_t *
 					return;
 				if ((op & 0x3) > 1)
 					return; // param or temp
-				if ((op & 0x3) && s->execution_stack[s->execution_stack_pos].local_segment > 0)
+				if ((op & 0x3) && s->_executionStack[s->execution_stack_pos].local_segment > 0)
 					return; // locals and not running in script.000
 				if (paramf1 != _debug_seek_special)
 					return; // CORRECT global?
diff --git a/engines/sci/engine/state.cpp b/engines/sci/engine/state.cpp
index e6266c65a2..21f0452aee 100644
--- a/engines/sci/engine/state.cpp
+++ b/engines/sci/engine/state.cpp
@@ -111,11 +111,9 @@ EngineState::EngineState() : _dirseeker(this) {
 
 	kernel_opt_flags = 0;
 
-	execution_stack = 0;
-	execution_stack_size = 0;
 	execution_stack_pos = 0;
 	execution_stack_base = 0;
-	execution_stack_pos_changed = 0;
+	_executionStackPosChanged = false;
 
 	r_acc = NULL_REG;
 	r_amp_rest = 0;
diff --git a/engines/sci/engine/state.h b/engines/sci/engine/state.h
index e522176a9b..849076fa3e 100644
--- a/engines/sci/engine/state.h
+++ b/engines/sci/engine/state.h
@@ -209,15 +209,14 @@ public:
 
 	/* VM Information */
 
-	ExecStack *execution_stack; /**< The execution stack */
-	int execution_stack_size;      /**< Number of stack frames allocated */
+	Common::Array<ExecStack> _executionStack; /**< The execution stack */
 	int execution_stack_pos;       /**< Position on the execution stack */
 	/**
 	 * When called from kernel functions, the vm is re-started recursively on
 	 * the same stack. This variable contains the stack base for the current vm.
 	 */
 	int execution_stack_base;
-	int execution_stack_pos_changed;   /**< Set to 1 if the execution stack position should be re-evaluated by the vm */
+	bool _executionStackPosChanged;   /**< Set to true if the execution stack position should be re-evaluated by the vm */
 
 	reg_t r_acc; /**< Accumulator */
 	unsigned int r_amp_rest; /**< &rest register (only used for save games) */
diff --git a/engines/sci/engine/vm.cpp b/engines/sci/engine/vm.cpp
index 6f93da093e..e776b9e598 100644
--- a/engines/sci/engine/vm.cpp
+++ b/engines/sci/engine/vm.cpp
@@ -297,14 +297,14 @@ static void _exec_varselectors(EngineState *s) {
 	// Executes all varselector read/write ops on the TOS
 	// Now check the TOS to execute all varselector entries
 	if (s->execution_stack_pos >= 0)
-		while (s->execution_stack[s->execution_stack_pos].type == EXEC_STACK_TYPE_VARSELECTOR) {
+		while (s->_executionStack[s->execution_stack_pos].type == EXEC_STACK_TYPE_VARSELECTOR) {
 			// varselector access?
-			if (s->execution_stack[s->execution_stack_pos].argc) { // write?
-				reg_t temp = s->execution_stack[s->execution_stack_pos].variables_argp[1];
-				*(s->execution_stack[s->execution_stack_pos].addr.varp) = temp;
+			if (s->_executionStack[s->execution_stack_pos].argc) { // write?
+				reg_t temp = s->_executionStack[s->execution_stack_pos].variables_argp[1];
+				*(s->_executionStack[s->execution_stack_pos].addr.varp) = temp;
 
 			} else // No, read
-				s->r_acc = *(s->execution_stack[s->execution_stack_pos].addr.varp);
+				s->r_acc = *(s->_executionStack[s->execution_stack_pos].addr.varp);
 
 			--(s->execution_stack_pos);
 		}
@@ -321,7 +321,6 @@ ExecStack *send_selector(EngineState *s, reg_t send_obj, reg_t work_obj, StackPt
 	int selector;
 	int argc;
 	int origin = s->execution_stack_pos; // Origin: Used for debugging
-	ExecStack *retval = s->execution_stack + s->execution_stack_pos;
 	int print_send_action = 0;
 	// We return a pointer to the new active ExecStack
 
@@ -460,18 +459,17 @@ ExecStack *send_selector(EngineState *s, reg_t send_obj, reg_t work_obj, StackPt
 	while (!sendCalls.empty()) {
 		CallsStruct call = sendCalls.pop();
 		if (call.type == EXEC_STACK_TYPE_VARSELECTOR) // Write/read variable?
-			retval = add_exec_stack_varselector(s, work_obj, call.argc, call.argp,
+			add_exec_stack_varselector(s, work_obj, call.argc, call.argp,
 			                                    call.selector, call.address.var, origin);
 		else
-			retval = add_exec_stack_entry(s, call.address.func, call.sp, work_obj,
+			add_exec_stack_entry(s, call.address.func, call.sp, work_obj,
 			                         call.argc, call.argp,
 			                         call.selector, send_obj, origin, SCI_XS_CALLEE_LOCALS);
 	}
 
 	_exec_varselectors(s);
 
-	retval = s->execution_stack + s->execution_stack_pos;
-	return retval;
+	return &(s->_executionStack[s->execution_stack_pos]);
 }
 
 ExecStack *add_exec_stack_varselector(EngineState *s, reg_t objp, int argc, StackPtr argp, Selector selector, reg_t *address, int origin) {
@@ -488,17 +486,14 @@ ExecStack *add_exec_stack_entry(EngineState *s, reg_t pc, StackPtr sp, reg_t obj
 								   StackPtr argp, Selector selector, reg_t sendp, int origin, SegmentId locals_segment) {
 	// Returns new TOS element for the execution stack
 	// locals_segment may be -1 if derived from the called object
-	ExecStack *xstack = NULL;
 
-	if (!s->execution_stack)
-		s->execution_stack = (ExecStack *)sci_malloc(sizeof(ExecStack) * (s->execution_stack_size = 16));
+	++s->execution_stack_pos;
+	if (s->execution_stack_pos >= (int)s->_executionStack.size()) // Out of stack space?
+		s->_executionStack.resize(s->execution_stack_pos+1);
 
-	if (++(s->execution_stack_pos) == s->execution_stack_size) // Out of stack space?
-		s->execution_stack = (ExecStack*)sci_realloc(s->execution_stack, sizeof(ExecStack) * (s->execution_stack_size += 8));
+	//sciprintf("Exec stack: [%d/%d], origin %d, at %p\n", s->execution_stack_pos, s->_executionStack.size(), origin, s->execution_stack);
 
-	//sciprintf("Exec stack: [%d/%d], origin %d, at %p\n", s->execution_stack_pos, s->execution_stack_size, origin, s->execution_stack);
-
-	xstack = s->execution_stack + s->execution_stack_pos;
+	ExecStack *xstack = &(s->_executionStack[s->execution_stack_pos]);
 
 	xstack->objp = objp;
 	if (locals_segment != SCI_XS_CALLEE_LOCALS)
@@ -596,7 +591,7 @@ void run_vm(EngineState *s, int restoring) {
 	int restadjust = s->r_amp_rest;
 	// &rest adjusts the parameter count by this value
 	// Current execution data:
-	ExecStack *xs = s->execution_stack + s->execution_stack_pos;
+	ExecStack *xs = &(s->_executionStack[s->execution_stack_pos]);
 	ExecStack *xs_new = NULL;
 	Object *obj = obj_get(s, xs->objp);
 	Script *local_script = script_locate_by_segment(s, xs->local_segment);
@@ -637,7 +632,7 @@ void run_vm(EngineState *s, int restoring) {
 
 
 
-	s->execution_stack_pos_changed = 1; // Force initialization
+	s->_executionStackPosChanged = true; // Force initialization
 
 	while (1) {
 		byte opcode;
@@ -649,10 +644,10 @@ void run_vm(EngineState *s, int restoring) {
 
 		old_pc_offset = xs->addr.pc.offset;
 
-		if (s->execution_stack_pos_changed) {
+		if (s->_executionStackPosChanged) {
 			Script *scr;
-			xs = s->execution_stack + s->execution_stack_pos;
-			s->execution_stack_pos_changed = 0;
+			xs = &(s->_executionStack[s->execution_stack_pos]);
+			s->_executionStackPosChanged = false;
 
 			scr = script_locate_by_segment(s, xs->addr.pc.segment);
 			if (!scr) {
@@ -1003,7 +998,7 @@ void run_vm(EngineState *s, int restoring) {
 			restadjust = 0; // Used up the &rest adjustment
 			xs->sp = call_base;
 
-			s->execution_stack_pos_changed = 1;
+			s->_executionStackPosChanged = true;
 			break;
 		}
 
@@ -1037,8 +1032,8 @@ void run_vm(EngineState *s, int restoring) {
 				// Calculate xs again: The kernel function might
 				// have spawned a new VM
 
-				xs_new = s->execution_stack + s->execution_stack_pos;
-				s->execution_stack_pos_changed = 1;
+				xs_new = &(s->_executionStack[s->execution_stack_pos]);
+				s->_executionStackPosChanged = true;
 
 				if (s->version >= SCI_VERSION_FTU_NEW_SCRIPT_HEADER)
 					restadjust = s->r_amp_rest;
@@ -1055,7 +1050,7 @@ void run_vm(EngineState *s, int restoring) {
 			xs_new = execute_method(s, 0, opparams[0], s_temp, xs->objp, xs->sp[0].offset, xs->sp);
 			restadjust = 0; // Used up the &rest adjustment
 			if (xs_new)    // in case of error, keep old stack
-				s->execution_stack_pos_changed = 1;
+				s->_executionStackPosChanged = true;
 			break;
 
 		case 0x23: // calle
@@ -1068,21 +1063,21 @@ void run_vm(EngineState *s, int restoring) {
 			restadjust = 0; // Used up the &rest adjustment
 
 			if (xs_new)  // in case of error, keep old stack
-				s->execution_stack_pos_changed = 1;
+				s->_executionStackPosChanged = true;
 			break;
 
 		case 0x24: // ret
 			do {
 				StackPtr old_sp2 = xs->sp;
 				StackPtr old_fp = xs->fp;
-				ExecStack *old_xs = s->execution_stack + s->execution_stack_pos;
+				ExecStack *old_xs = &(s->_executionStack[s->execution_stack_pos]);
 
 				if (s->execution_stack_pos == s->execution_stack_base) { // Have we reached the base?
 					s->execution_stack_base = old_execution_stack_base; // Restore stack base
 
 					--(s->execution_stack_pos);
 
-					s->execution_stack_pos_changed = 1;
+					s->_executionStackPosChanged = true;
 					s->r_amp_rest = restadjust; // Update &rest
 					return; // "Hard" return
 				}
@@ -1098,8 +1093,8 @@ void run_vm(EngineState *s, int restoring) {
 				// Not reached the base, so let's do a soft return
 				--(s->execution_stack_pos);
 				xs = old_xs - 1;
-				s->execution_stack_pos_changed = 1;
-				xs = s->execution_stack + s->execution_stack_pos;
+				s->_executionStackPosChanged = true;
+				xs = &(s->_executionStack[s->execution_stack_pos]);
 
 				if (xs->sp == CALL_SP_CARRY // Used in sends to 'carry' the stack pointer
 				        || xs->type != EXEC_STACK_TYPE_CALL) {
@@ -1109,7 +1104,7 @@ void run_vm(EngineState *s, int restoring) {
 
 			} while (xs->type == EXEC_STACK_TYPE_VARSELECTOR);
 			// Iterate over all varselector accesses
-			s->execution_stack_pos_changed = 1;
+			s->_executionStackPosChanged = true;
 			xs_new = xs;
 
 			break;
@@ -1122,7 +1117,7 @@ void run_vm(EngineState *s, int restoring) {
 			xs_new = send_selector(s, s->r_acc, s->r_acc, s_temp, (int)(opparams[0] >> 1) + (uint16)restadjust, xs->sp);
 
 			if (xs_new && xs_new != xs)
-				s->execution_stack_pos_changed = 1;
+				s->_executionStackPosChanged = true;
 
 			restadjust = 0;
 
@@ -1140,7 +1135,7 @@ void run_vm(EngineState *s, int restoring) {
 			xs_new = send_selector(s, xs->objp, xs->objp, s_temp, (int)(opparams[0] >> 1) + (uint16)restadjust, xs->sp);
 
 			if (xs_new && xs_new != xs)
-				s->execution_stack_pos_changed = 1;
+				s->_executionStackPosChanged = true;
 
 			restadjust = 0;
 			break;
@@ -1158,7 +1153,7 @@ void run_vm(EngineState *s, int restoring) {
 				xs_new = send_selector(s, r_temp, xs->objp, s_temp, (int)(opparams[1] >> 1) + (uint16)restadjust, xs->sp);
 
 				if (xs_new && xs_new != xs)
-					s->execution_stack_pos_changed = 1;
+					s->_executionStackPosChanged = true;
 
 				restadjust = 0;
 			}
@@ -1457,12 +1452,12 @@ void run_vm(EngineState *s, int restoring) {
 
 		} // switch(opcode >> 1)
 
-		if (s->execution_stack_pos_changed) // Force initialization
+		if (s->_executionStackPosChanged) // Force initialization
 			xs = xs_new;
 
 #ifndef DISABLE_VALIDATIONS
-		if (xs != s->execution_stack + s->execution_stack_pos) {
-			sciprintf("Error: xs is stale (%d vs %d); last command was %02x\n", (int)(xs - s->execution_stack), s->execution_stack_pos, opnumber);
+		if (xs != &(s->_executionStack[s->execution_stack_pos])) {
+			sciprintf("Error: xs is stale (%d vs %d); last command was %02x\n", (int)(xs - &s->_executionStack[0]), s->execution_stack_pos, opnumber);
 		}
 #endif
 		if (script_error_flag) {
@@ -2018,14 +2013,13 @@ static EngineState *_game_run(EngineState *s, int restoring) {
 	EngineState *successor = NULL;
 	int game_is_finished = 0;
 	do {
-		s->execution_stack_pos_changed = 0;
+		s->_executionStackPosChanged = false;
 		run_vm(s, (successor || restoring) ? 1 : 0);
 		if (s->restarting_flags & SCI_GAME_IS_RESTARTING_NOW) { // Restart was requested?
 			successor = NULL;
-			free(s->execution_stack);
-			s->execution_stack = NULL;
+			s->_executionStack.clear();
 			s->execution_stack_pos = -1;
-			s->execution_stack_pos_changed = 0;
+			s->_executionStackPosChanged = false;
 
 			game_exit(s);
 			script_free_engine(s);