GLK: ADVSYS: Implementing VM opcodes

3 files changed, 44 insertions, 4 deletions

diff --git a/engines/glk/advsys/game.cpp b/engines/glk/advsys/game.cpp
index a20178d9e2..22b1d11476 100644
--- a/engines/glk/advsys/game.cpp
+++ b/engines/glk/advsys/game.cpp
@@ -220,13 +220,15 @@ int Game::getObjectProperty(int obj, int prop) {
 	return NIL;
 }
 
-void Game::setObjectProperty(int obj, int prop, int val) {
+int Game::setObjectProperty(int obj, int prop, int val) {
 	int field;
 
 	for (; obj; obj = getObjectField(obj, O_CLASS)) {
 		if ((field = findProperty(obj, prop)) != 0)
 			return setObjectField(obj, field, val);
 	}
+
+	return NIL;
 }
 
 int Game::getObjectLocation(int obj) const {
diff --git a/engines/glk/advsys/game.h b/engines/glk/advsys/game.h
index 40b4fb65ec..5ffb31b20e 100644
--- a/engines/glk/advsys/game.h
+++ b/engines/glk/advsys/game.h
@@ -250,7 +250,7 @@ public:
 	/**
 	 * Sets an object property
 	 */
-	void setObjectProperty(int obj, int prop, int val);
+	int setObjectProperty(int obj, int prop, int val);
 
 	/**
 	 * Gets a field from an object
@@ -262,8 +262,9 @@ public:
 	/**
 	 * Sets a field in an object
 	 */
-	void setObjectField(int obj, int offset, int val) {
+	int setObjectField(int obj, int offset, int val) {
 		WRITE_LE_UINT16(_residentBase + getObjectLocation(obj) + offset, val);
+		return val;
 	}
 
 	/**
diff --git a/engines/glk/advsys/vm.cpp b/engines/glk/advsys/vm.cpp
index a467a592d2..46d2133dd0 100644
--- a/engines/glk/advsys/vm.cpp
+++ b/engines/glk/advsys/vm.cpp
@@ -25,6 +25,8 @@
 namespace Glk {
 namespace AdvSys {
 
+#define TRUE -1
+
 OpcodeMethod VM::_METHODS[0x34] = {
 	&VM::opBRT,
 	&VM::opBRF,
@@ -117,71 +119,105 @@ void VM::executeOpcode() {
 		error("Unknown opcode %x at offset %d", opcode, _pc);
 	}
 }
-
 void VM::opBRT() {
+	_pc = _stack.back() ? readCodeWord() : _pc + 2;
 }
 
 void VM::opBRF() {
+	_pc = !_stack.back() ? readCodeWord() : _pc + 2;
 }
 
 void VM::opBR() {
+	_pc = readCodeWord();
 }
 
 void VM::opT() {
+	_stack.back() = TRUE;
 }
 
 void VM::opNIL() {
+	_stack.back() = NIL;
 }
 
 void VM::opPUSH() {
+	_stack.push(NIL);
 }
 
 void VM::opNOT() {
+	_stack.back() = _stack.back() ? NIL : TRUE;
 }
 
 void VM::opADD() {
+	int v = _stack.pop();
+	_stack.back() += v;
 }
 
 void VM::opSUB() {
+	int v = _stack.pop();
+	_stack.back() -= v;
 }
 
 void VM::opMUL() {
+	int v = _stack.pop();
+	_stack.back() *= v;
 }
 
 void VM::opDIV() {
+	int v = _stack.pop();
+	_stack.back() = (v == 0) ? 0 : _stack.back() / v;
 }
 
 void VM::opREM() {
+	int v = _stack.pop();
+	_stack.back() = (v == 0) ? 0 : _stack.back() % v;
 }
 
 void VM::opBAND() {
+	int v = _stack.pop();
+	_stack.back() &= v;
 }
 
 void VM::opBOR() {
+	int v = _stack.pop();
+	_stack.back() |= v;
 }
 
 void VM::opBNOT() {
+	_stack.back() = ~_stack.back();
 }
 
 void VM::opLT() {
+	int v = _stack.pop();
+	_stack.back() = (_stack.back() < v) ? TRUE : NIL;
 }
 
 void VM::opEQ() {
+	int v = _stack.pop();
+	_stack.back() = (_stack.back() == v) ? TRUE : NIL;
 }
 
 void VM::opGT() {
+	int v = _stack.pop();
+	_stack.back() = (_stack.back() > v) ? TRUE : NIL;
 }
 
 void VM::opLIT() {
+	_stack.back() = readCodeWord();
 }
 
 void VM::opVAR() {
+	_stack.back() = getVariable(readCodeWord());
 }
 
 void VM::opGETP() {
+	int v = _stack.pop();
+	_stack.back() = getObjectProperty(_stack.back(), v);
 }
 
 void VM::opSETP() {
+	int v3 = _stack.pop();
+	int v2 = _stack.pop();
+	_stack.back() = setObjectProperty(_stack.back(), v2, v3);
 }
 
 void VM::opSET() {
@@ -215,6 +251,7 @@ void VM::opCALL() {
 }
 
 void VM::opSVAR() {
+	_stack.back() = getVariable(readCodeByte());
 }
 
 void VM::opSSET() {