Function Script_Run

src/script/script.c:314–565

* Run the next opcode of a script. * * @param script The script engine to run. * @return Returns false if and only if there was an scripting error, like * invalid opcode. */

 *   invalid opcode.
 */
bool Script_Run(ScriptEngine *script)
{
	ScriptInfo *scriptInfo;
	uint16 current, parameter;
	uint8 opcode;

	if (!Script_IsLoaded(script)) return false;
	scriptInfo = script->scriptInfo;

	current = BETOH16(*script->script);
	script->script++;

	opcode    = (current >> 8) & 0x1F;
	parameter = 0;

	if ((current & 0x8000) != 0) {
		/* When this flag is set, the instruction is a GOTO with a 13bit address */
		opcode = 0;
		parameter = current & 0x7FFF;
	} else if ((current & 0x4000) != 0) {
		/* When this flag is set, the parameter is part of the instruction */
		parameter = (int16)(int8)(current & 0xFF);
	} else if ((current & 0x2000) != 0) {
		/* When this flag is set, the parameter is in the next opcode */
		parameter = BETOH16(*script->script);
		script->script++;
	}

	switch (opcode) {
		case SCRIPT_JUMP: {
			script->script = scriptInfo->start + parameter;
			return true;
		}

		case SCRIPT_SETRETURNVALUE: {
			script->returnValue = parameter;
			return true;
		}

		case SCRIPT_PUSH_RETURN_OR_LOCATION: {
			if (parameter == 0) { /* PUSH RETURNVALUE */
				STACK_PUSH(script->returnValue);
				return true;
			}

			if (parameter == 1) { /* PUSH NEXT LOCATION + FRAMEPOINTER */
				uint32 location;
				location = (uint32)(script->script - scriptInfo->start) + 1;

				STACK_PUSH(location);
				STACK_PUSH(script->framePointer);
				script->framePointer = script->stackPointer + 2;

				return true;
			}

			Script_Error("Unknown parameter %d for opcode 2", parameter);
			script->script = NULL;