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-rw-r--r--engines/draci/script.cpp64
-rw-r--r--engines/draci/script.h7
2 files changed, 54 insertions, 17 deletions
diff --git a/engines/draci/script.cpp b/engines/draci/script.cpp
index 9047d6c8cc..c676ef9d46 100644
--- a/engines/draci/script.cpp
+++ b/engines/draci/script.cpp
@@ -41,9 +41,9 @@ void Script::setupCommandList() {
static const GPL2Command gplCommands[] = {
{ 0, 0, "gplend", 0, { 0 }, NULL },
{ 0, 1, "exit", 0, { 0 }, NULL },
- { 1, 1, "goto", 1, { 3 }, NULL },
- { 2, 1, "Let", 2, { 3, 4 }, NULL },
- { 3, 1, "if", 2, { 4, 3 }, NULL },
+ { 1, 1, "goto", 1, { 3 }, &Script::c_Goto },
+ { 2, 1, "Let", 2, { 3, 4 }, &Script::c_Let },
+ { 3, 1, "if", 2, { 4, 3 }, &Script::c_If },
{ 4, 1, "Start", 2, { 3, 2 }, &Script::start },
{ 5, 1, "Load", 2, { 3, 2 }, &Script::load },
{ 5, 2, "StartPlay", 2, { 3, 2 }, NULL },
@@ -246,6 +246,27 @@ void Script::start(Common::Queue<int> &params) {
_vm->_anims->play(animID);
}
+void Script::c_If(Common::Queue<int> &params) {
+ int expression = params.pop();
+ int jump = params.pop();
+
+ if (expression)
+ _jump = jump;
+}
+
+void Script::c_Goto(Common::Queue<int> &params) {
+ int jump = params.pop();
+
+ _jump = jump;
+}
+
+void Script::c_Let(Common::Queue<int> &params) {
+ int var = params.pop() - 1;
+ int value = params.pop();
+
+ _vm->_game->setVariable(var, value);
+}
+
/**
* @brief Evaluates mathematical expressions
* @param reader Stream reader set to the beginning of the expression
@@ -258,7 +279,7 @@ int Script::handleMathExpression(Common::MemoryReadStream &reader) {
GPL2Function func;
// Read in initial math object
- obj = (mathExpressionObject)reader.readUint16LE();
+ obj = (mathExpressionObject)reader.readSint16LE();
int value;
int arg1, arg2, res;
@@ -277,13 +298,13 @@ int Script::handleMathExpression(Common::MemoryReadStream &reader) {
// If the object type is not known, assume that it's a number
default:
case kMathNumber:
- value = reader.readUint16LE();
+ value = reader.readSint16LE();
stk.push(value);
debugC(3, kDraciBytecodeDebugLevel, "\t\tnumber: %d", value);
break;
case kMathOperator:
- value = reader.readUint16LE();
+ value = reader.readSint16LE();
arg1 = stk.pop();
arg2 = stk.pop();
@@ -301,7 +322,7 @@ int Script::handleMathExpression(Common::MemoryReadStream &reader) {
break;
case kMathVariable:
- value = reader.readUint16LE();
+ value = reader.readSint16LE();
stk.push(_vm->_game->getVariable(value-1));
@@ -310,7 +331,7 @@ int Script::handleMathExpression(Common::MemoryReadStream &reader) {
break;
case kMathFunctionCall:
- value = reader.readUint16LE();
+ value = reader.readSint16LE();
// Fetch function
func = _functionList[value-1];
@@ -337,7 +358,7 @@ int Script::handleMathExpression(Common::MemoryReadStream &reader) {
break;
}
- obj = (mathExpressionObject) reader.readUint16LE();
+ obj = (mathExpressionObject) reader.readSint16LE();
}
return stk.pop();
@@ -374,12 +395,12 @@ const GPL2Command *Script::findCommand(byte num, byte subnum) {
}
/**
- * @brief GPL2 bytecode disassembler
+ * @brief GPL2 bytecode interpreter
* @param program GPL program in the form of a GPL2Program struct
* offset Offset into the program where execution should begin
*
* GPL2 is short for Game Programming Language 2 which is the script language
- * used by Draci Historie. This is a simple disassembler for the language.
+ * used by Draci Historie. This is the interpreter for the language.
*
* A compiled GPL2 program consists of a stream of bytes representing commands
* and their parameters. The syntax is as follows:
@@ -423,6 +444,17 @@ int Script::run(GPL2Program program, uint16 offset) {
const GPL2Command *cmd;
do {
+ debugC(3, kDraciBytecodeDebugLevel,
+ "Program length = %d Current position = %d "
+ "Jump = %d New Position = %d", program._length,
+ reader.pos(), _jump, reader.pos() + _jump);
+
+ // Account for GPL jump that some commands set
+ reader.seek(reader.pos() + _jump);
+
+ // Reset jump
+ _jump = 0;
+
// Clear any parameters left on the stack from the previous command
// This likely won't be needed once all commands are implemented
params.clear();
@@ -440,22 +472,22 @@ int Script::run(GPL2Program program, uint16 offset) {
int tmp;
// Print command name
- debugC(2, kDraciBytecodeDebugLevel, "%s", cmd->_name.c_str());
+ debugC(1, kDraciBytecodeDebugLevel, "%s", cmd->_name.c_str());
for (int i = 0; i < cmd->_numParams; ++i) {
if (cmd->_paramTypes[i] == 4) {
- debugC(3, kDraciBytecodeDebugLevel, "\t<MATHEXPR>");
+ debugC(2, kDraciBytecodeDebugLevel, "\t<MATHEXPR>");
params.push(handleMathExpression(reader));
}
else {
- tmp = reader.readUint16LE();
+ tmp = reader.readSint16LE();
params.push(tmp);
- debugC(3, kDraciBytecodeDebugLevel, "\t%hu", tmp);
+ debugC(2, kDraciBytecodeDebugLevel, "\t%d", tmp);
}
}
}
else {
- debugC(2, kDraciBytecodeDebugLevel, "Unknown opcode %hu, %hu",
+ debugC(1, kDraciBytecodeDebugLevel, "Unknown opcode %d, %d",
num, subnum);
}
diff --git a/engines/draci/script.h b/engines/draci/script.h
index 89109aebc5..7007e563c4 100644
--- a/engines/draci/script.h
+++ b/engines/draci/script.h
@@ -86,17 +86,22 @@ struct GPL2Program {
class Script {
public:
- Script(DraciEngine *vm) : _vm(vm) { setupCommandList(); };
+ Script(DraciEngine *vm) : _vm(vm), _jump(0) { setupCommandList(); };
int run(GPL2Program program, uint16 offset);
private:
+ int _jump;
+
/** List of all GPL commands. Initialised in the constructor. */
const GPL2Command *_commandList;
const GPL2Operator *_operatorList;
const GPL2Function *_functionList;
+ void c_If(Common::Queue<int> &params);
+ void c_Goto(Common::Queue<int> &params);
+ void c_Let(Common::Queue<int> &params);
void load(Common::Queue<int> &params);
void start(Common::Queue<int> &params);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-17 10:21:16 +0000