Variable refactoring pt.1 - Change union to pointer.

Depfile

@@ -2,7 +2,7 @@
 Artifact=kernel
 TempDir=obj
 SourceDir=asm src
-Files=trainscript/trainscript.y trainscript/trainscript.l trainscript/tsvm.cpp
+Files=trainscript/trainscript.y trainscript/trainscript.l trainscript/tsvm.cpp trainscript/variable.cpp
 AdditionalObjects=obj/main.o
 
 LexUseCpp

Makefile

@@ -12,8 +12,8 @@ YACC = bison
 # File Lists
 SRCS_AS  = asm/dynamic.S asm/intr_common_handler.S asm/multiboot.S asm/start.S
 SRCS_CC  = src/console.c src/init.c src/interrupts.c src/malloc.c src/pmm.c src/serial.c src/stdlib.c src/timer.c src/vmm.c
-SRCS_CXX = trainscript/tsvm.cpp src/cplusplus.cpp src/vm.cpp obj/trainscript.yy.cpp obj/trainscript.tab.cpp
+SRCS_CXX = trainscript/tsvm.cpp trainscript/variable.cpp src/cplusplus.cpp src/vm.cpp obj/trainscript.yy.cpp obj/trainscript.tab.cpp
-OBJS     = obj/tsvm.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
+OBJS     = obj/tsvm.o obj/variable.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
 
 # Flags
 FLAGS    = -m32 -Dnullptr=0 -D__cdecl="__attribute__((cdecl))" -mno-sse -mno-sse2 -mno-mmx
@@ -27,10 +27,10 @@ all: kernel
 
 .PHONY: clean
 clean:
-	$(RM) obj/trainscript.yy.cpp obj/trainscript.tab.cpp obj/tsvm.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
+	$(RM) obj/trainscript.yy.cpp obj/trainscript.tab.cpp obj/tsvm.o obj/variable.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
 
-kernel: obj/tsvm.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
+kernel: obj/tsvm.o obj/variable.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
-	$(LD) $(FLAGS) $(LDFLAGS) -o $@ obj/tsvm.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
+	$(LD) $(FLAGS) $(LDFLAGS) -o $@ obj/tsvm.o obj/variable.o obj/dynamic.o obj/intr_common_handler.o obj/multiboot.o obj/start.o obj/console.o obj/init.o obj/interrupts.o obj/malloc.o obj/pmm.o obj/serial.o obj/stdlib.o obj/timer.o obj/vmm.o obj/cplusplus.o obj/vm.o obj/trainscript.yy.o obj/trainscript.tab.o obj/main.o
 
 # src/console.c
 obj/console.o: src/console.c include/console.h include/stdlib.h \
@@ -96,6 +96,13 @@ obj/tsvm.o: trainscript/tsvm.cpp include/stdlib.h include/varargs.h \
  obj/trainscript.tab.hpp trainscript/trainscript.l.h include/string.h
 	$(CXX) -iquoteobj  $(FLAGS) $(CXXFLAGS) -o $@ -c trainscript/tsvm.cpp
 
+# trainscript/variable.cpp
+obj/variable.o: trainscript/variable.cpp include/kernel.h \
+ trainscript/variable.hpp trainscript/type.hpp trainscript/types.hpp \
+ include/ker/string.hpp include/stdlib.h include/varargs.h \
+ include/config.h include/malloc.h trainscript/typeid.hpp
+	$(CXX) -iquoteobj  $(FLAGS) $(CXXFLAGS) -o $@ -c trainscript/variable.cpp
+
 # src/cplusplus.cpp
 obj/cplusplus.o: src/cplusplus.cpp include/stdlib.h include/varargs.h \
  include/config.h include/malloc.h include/console.h include/ker/new.hpp

README.md

@@ -48,7 +48,26 @@ It also features a surveillance mode that logs all allocations / frees. It can b
 |0x20 - 0x27| IRQ0 - IRQ7       |
 |0x28 - 0x2F| IRQ8 - IRQ15      |
 
-### 
+## Virtual Machine Architecture
+
+### Type Format
+The virtual machine supports 5 base types:
+
+| Name    | Description                                    | Size   |
+|---------|------------------------------------------------|--------|
+| Void    | A type that specifies a non-existent value.    | 0      |
+| Int     | An integral number.                            | 32     |
+| Real    | A decimal number.                              | 32/64¹ |
+| Text    | A string value containing a sequence of bytes. | any²   |
+| Bool    | A boolen value, either `true` or `false`.      | 1³     |
+
+¹) A real number is either a float (32 bits) or a double (64 bits) depending on the configuration in `types.hpp`.
+²) A string value is sized the length of the string in bytes plus the size of the length specifier (32 bits).
+³) A boolean is representet as a 1 bit value but due to architecture limitations it is stored with 32 bits.
+
+### Variable Format
+Variables are stored in a `type+pointer` format where `type` stores the type of the variable and `pointer` either a pointer to the variable value or, if `type` is a pointer type, the pointer value of the variable.
+
 
 ## OS Architecture
 To be done.

src/vm.cpp

@@ -82,33 +82,22 @@ Variable NativeMethod::invoke(Vector<Variable> arguments)
 	// Copy arguments
 	size_t stackSize = 0;
 	for(size_t i = 0; i < arguments.length(); i++) {
-		if(arguments[i].type != this->parameters[i]) {
+		if(arguments[i].type() != this->parameters[i]) {
 			// die_extra("NativeMethod.InvalidArgumentType", arguments[i].type.name());
 		}
-		switch(arguments[i].type.id) {
+		stackSize += arguments[i].type().size();
-			case TypeID::Bool: stackSize += sizeof(Int); break;
-			case TypeID::Int:  stackSize += sizeof(Int); break;
-			case TypeID::Real: stackSize += sizeof(Real); break;
-			default: die_extra("NativeMethod.InvalidArgument", arguments[i].type.name()); break;
-		}
 	}
 
 	uint8_t *stack = (uint8_t*)malloc(stackSize);
 	uint8_t *stackPtr = stack;
 	for(size_t i = 0; i < arguments.length(); i++) {
-		switch(arguments[i].type.id) {
+
-			case TypeID::Bool:
+		size_t size = arguments[i].type().size();
-				*reinterpret_cast<Int*>(stackPtr) = arguments[i].boolean ? 1 : 0;
+		void *data = arguments[i].data();
-				stackPtr += sizeof(Int);
+
-				break;
+		if(size > 0) {
-			case TypeID::Int:
+			memcpy(stackPtr, data, size);
-				*reinterpret_cast<Int*>(stackPtr) = arguments[i].integer;
+			stackPtr += size;
-				stackPtr += sizeof(Int);
-				break;
-			case TypeID::Real:
-				*reinterpret_cast<Real*>(stackPtr) = arguments[i].real;
-				stackPtr += sizeof(Real);
-				break;
 		}
 	}
 
@@ -116,7 +105,7 @@ Variable NativeMethod::invoke(Vector<Variable> arguments)
 
 	free(stack);
 
-	return mkvar((Int)0);
+	return Type::Int.createInstance();
 }
 
 extern "C" void __cdecl printInt(int i) {

trainOS.pro

@@ -16,7 +16,8 @@ SOURCES += \
     src/timer.c \
     src/cplusplus.cpp \
     src/vm.cpp \
-    src/serial.c
+    src/serial.c \
+    trainscript/variable.cpp
 
 HEADERS += \
 	include/console.h \

trainscript/common.h

@@ -49,7 +49,7 @@ struct ParserData
 struct VariableDeclaration
 {
 	char *name;
-	trainscript::Variable variable;
+	trainscript::Type type;
 };
 
 struct LocalVariable

trainscript/instructions.hpp

@@ -46,7 +46,7 @@ namespace trainscript
 		}
 
 		Type expectedResult(ExecutionContext &) const override {
-			return this->value.type;
+			return this->value.type();
 		}
 	};
 
@@ -79,7 +79,7 @@ namespace trainscript
 			if(var == nullptr) {
 				return Type::Invalid;
 			} else {
-				return var->type;
+				return var->type();
 			}
 		}
 	};
@@ -109,18 +109,13 @@ namespace trainscript
 				die_extra("VariableAssignmentExpression.VariableNotFound", this->variableName.str());
 			}
 
-			if(target->type != result.type) {
+			if(target->type() != result.type()) {
-				die_extra("VariableAssignmentExpression.ExpectedType", result.type.name());
+				die_extra("VariableAssignmentExpression.ExpectedType", result.type().name());
 			}
 
-			switch(target->type.id) {
+			*target = result;
-				case TypeID::Int: target->integer = result.integer; break;
-				case TypeID::Real: target->real = result.real; break;
-				case TypeID::Bool: target->boolean = result.boolean; break;
-				default: break;
-			}
 
-			return result;
+			return *target;
 		}
 
 		bool validate(ExecutionContext &context, ker::String &errorCode) const override {
@@ -143,7 +138,7 @@ namespace trainscript
 				errorCode = "Variable " + this->variableName + " not found.";
 				return false;
 			}
-			if(var->type != result) {
+			if(var->type() != result) {
 				errorCode = "Variable assignment has invalid type.";
 				return false;
 			}
@@ -248,14 +243,14 @@ namespace trainscript
 			Variable left = this->lhs->execute(context);
 			Variable right = this->rhs->execute(context);
 
-			if(left.type != right.type) {
+			if(left.type() != right.type()) {
 				die("ArithmeticExpression.TypeMismatch");
 			}
 
 			Variable result = OP(left, right);
 
-			if(result.type.usable() == false) {
+			if(result.type().usable() == false) {
-				die_extra("ArithmeticExpression.InvalidResult", result.type.name());
+				die_extra("ArithmeticExpression.InvalidResult", result.type().name());
 			}
 			return result;
 		}
@@ -324,13 +319,13 @@ namespace trainscript
 			}
 
 			Variable result = this->condition->execute(context);
-			if(result.type != Type::Boolean) {
+			if(result.type() != Type::Bool) {
-				die_extra("IfExpression.TypeMismatch", result.type.name());
+				die_extra("IfExpression.TypeMismatch", result.type().name());
 			}
-			if((result.boolean == true) && (this->blockTrue != nullptr)) {
+			if((result.value<Bool>() == true) && (this->blockTrue != nullptr)) {
 				this->blockTrue->execute(context);
 			}
-			if((result.boolean == false) && (this->blockFalse != nullptr)) {
+			if((result.value<Bool>() == false) && (this->blockFalse != nullptr)) {
 				this->blockFalse->execute(context);
 			}
 			return Variable::Void;
@@ -389,10 +384,10 @@ namespace trainscript
 			while(true)
 			{
 				Variable cond = this->condition->execute(context);
-				if(cond.type != Type::Boolean) {
+				if(cond.type() != Type::Bool) {
 					return Variable::Invalid;
 				}
-				if(cond.boolean == false) {
+				if(cond.value<Bool>() == false) {
 					break;
 				}
 

trainscript/trainscript.y

@@ -145,7 +145,7 @@ void yyerror(void *scanner, const char *s);
 input:
 	%empty
 |   input variableDeclaration SEMICOLON {
-        auto *var = new Variable($2.variable);
+		auto *var = new Variable($2.type.createInstance());
         context->module->variables.add( ker::String($2.name), var );
 	}
 |   input method {
@@ -328,9 +328,9 @@ elseIfLoop:
 ;
 
 expression:
-	INT                                         { $$ = new ConstantExpression(mkvar($1)); }
+	INT                                         { $$ = new ConstantExpression(Variable::fromInt($1)); }
-|	REAL                                        { $$ = new ConstantExpression(mkvar($1)); }
+|	REAL                                        { $$ = new ConstantExpression(Variable::fromReal($1)); }
-// |   TEXT                                     { $$ = new ConstantExpression(mkvar($1)); }
+// |   TEXT                                     { $$ = new ConstantExpression(Variable::fromText($1)); }
 |   IDENTIFIER                                  { $$ = new VariableExpression($1); }
 |   IDENTIFIER LBRACKET expressionList RBRACKET {
 		auto *call = new MethodInvokeExpression($1);
@@ -379,8 +379,7 @@ expressionList:
 variableDeclaration:
 	KW_VAR IDENTIFIER COLON typeName {
 		$$.name = $2;
-		$$.variable.type = $4;
+		$$.type = $4;
-		$$.variable.integer = 0; // Initialize with zeroes
 	}
 ;
 

trainscript/tsvm.cpp

@@ -15,14 +15,14 @@ namespace trainscript
 	const Type Type::Int = { TypeID::Int, 0 };
 	const Type Type::Real = { TypeID::Real, 0 };
 	const Type Type::Text = { TypeID::Text, 0 };
-	const Type Type::Boolean = { TypeID::Bool, 0 };
+	const Type Type::Bool = { TypeID::Bool, 0 };
 
     const Variable Variable::Invalid = { Type::Invalid, 0 };
     const Variable Variable::Void = { Type::Void, 0 };
     const Variable Variable::Int = { Type::Int, 0 };
     const Variable Variable::Real = { Type::Real, 0 };
     const Variable Variable::Text = { Type::Text, 0 };
-    const Variable Variable::Boolean = { Type::Boolean, 0 };
+	const Variable Variable::Bool = { Type::Bool, 0 };
 
 	bool Module::validate(ker::String &errorCode) const
 	{
@@ -101,9 +101,7 @@ namespace trainscript
 			context.add(var.first, var.second);
 		}
 
-		Variable returnVariable = {
+		Variable returnVariable = this->mReturnValue.second.createInstance();
-			this->mReturnValue.second, 0
-		};
 
 		if(this->mReturnValue.second.usable()) {
 			context.add(this->mReturnValue.first, &returnVariable);
@@ -112,7 +110,7 @@ namespace trainscript
 			die_extra("ScriptMethod::invoke", "Invalid argument count.");
 		}
 		for(size_t i = 0; i < this->mArguments.length(); i++) {
-			if(this->mArguments[i].second != arguments[i].type) {
+			if(this->mArguments[i].second != arguments[i].type()) {
 				die_extra("ScriptMethod::invoke", "Invalid argument type.");
 			}
 			auto *v = new Variable(arguments[i]);
@@ -120,7 +118,7 @@ namespace trainscript
 			context.add(this->mArguments[i].first, v);
 		}
 		for(auto local : this->mLocals) {
-			auto *v = new Variable { local.second, 0 };
+			auto *v = new Variable(local.second.createInstance());
 			temporaries.append(v);
 			context.add(local.first, v);
 		}
@@ -148,9 +146,7 @@ namespace trainscript
 			context.add(var.first, var.second);
 		}
 
-		Variable returnVariable = {
+		Variable returnVariable = this->mReturnValue.second.createInstance();
-			this->mReturnValue.second, 0
-		};
 
 		if(this->mReturnValue.second.usable()) {
 			if(context.get(this->mReturnValue.first) != nullptr) {
@@ -165,14 +161,14 @@ namespace trainscript
 				errorCode = "Parameter overlaps a variable.";
 				return false;
 			}
-			context.add(this->mArguments[i].first, new Variable { this->mArguments[i].second, 0 });
+			context.add(this->mArguments[i].first, new Variable(this->mArguments[i].second.createInstance()));
 		}
 		for(auto local : this->mLocals) {
 			if(context.get(local.first) != nullptr) {
 				errorCode = "Local variable overlaps a variable.";
 				return false;
 			}
-			context.add(local.first, new Variable { local.second, 0 });
+			context.add(local.first, new Variable(local.second.createInstance()));
 		}
 
 		if(this->block->validate(context, errorCode) == false) {
@@ -184,6 +180,7 @@ namespace trainscript
 
 	namespace ops
 	{
+		/*
 		Variable add(Variable lhs, Variable rhs)
 		{
 			switch(lhs.type.id) {
@@ -297,5 +294,7 @@ namespace trainscript
 					return Variable::Invalid;
 			}
 		}
+
+		*/
 	}
 }

trainscript/type.hpp

@@ -6,6 +6,8 @@
 
 namespace trainscript
 {
+	class Variable;
+
 	struct Type
 	{
 		TypeID id;
@@ -35,6 +37,12 @@ namespace trainscript
 		}
 
 		const char *name() const {
+			if(this->pointer > 0) {
+				static char str[64];
+				strcpy(str, this->dereference().name());
+				strcat(str, "*");
+				return str;
+			} else {
 				switch(id) {
 					case TypeID::Invalid: return "INVALID";
 					case TypeID::Void: return "VOID";
@@ -42,15 +50,36 @@ namespace trainscript
 					case TypeID::Real: return "REAL";
 					case TypeID::Text: return "TEXT";
 					case TypeID::Bool: return "BOOL";
-				default: return "unknown";
+					default: return "<UNKNOWN>";
 				}
 			}
+		}
+
+		size_t size() const
+		{
+			if(this->pointer > 0) {
+				return sizeof(void*);
+			} else {
+				switch(id) {
+					case TypeID::Invalid: return 0;
+					case TypeID::Void: return 0;
+					case TypeID::Int: return sizeof(Int);
+					case TypeID::Real: return sizeof(Real);
+					case TypeID::Text: return sizeof(Text);
+					case TypeID::Bool: return sizeof(Bool);
+					default: die("Type::size.UnknownTypeID");
+				}
+			}
+			return 0;
+		}
+
+		Variable createInstance() const;
 
 		static const Type Invalid;
 		static const Type Void;
 		static const Type Int;
 		static const Type Real;
 		static const Type Text;
-		static const Type Boolean;
+		static const Type Bool;
 	};
 }

trainscript/variable.cpp

@@ -0,0 +1,77 @@
+#include <kernel.h>
+#include "variable.hpp"
+
+namespace trainscript
+{
+	Variable::~Variable()
+	{
+		// Only free non-pointer types.
+		if(this->mType.pointer == 0) {
+			switch(this->mType.id) {
+#define DELETE(type) case TypeID::type: \
+					delete reinterpret_cast<trainscript::type*>(this->mValue); \
+					break
+				DELETE(Bool);
+				DELETE(Int);
+				DELETE(Real);
+				DELETE(Text);
+#undef DELETE
+			}
+		}
+	}
+
+	Variable &Variable::operator =(const Variable &other)
+	{
+		if(this->mType != other.mType) {
+			die_extra("Variable.operator=", "Type mismatch.");
+		}
+		if(this->mType.pointer == 0) {
+			switch(this->mType.id) {
+#define COPY(type) case TypeID::type: \
+					*reinterpret_cast<trainscript::type*>(this->mValue) = *reinterpret_cast<trainscript::type*>(other.mValue); \
+					break
+			COPY(Bool);
+			COPY(Int);
+			COPY(Real);
+			COPY(Text);
+#undef COPY
+			}
+		} else {
+			this->mValue = other.mValue;
+		}
+		return *this;
+	}
+
+	Variable Type::createInstance() const
+	{
+		void *value = nullptr;
+		if(this->pointer > 0) {
+			switch(this->id) {
+#define CREATE(type, initial) case TypeID::type: \
+					value = new trainscript::type(initial); \
+					break
+				CREATE(Bool, false);
+				CREATE(Int, 0);
+				CREATE(Real, 0.0);
+				CREATE(Text, "");
+				default:
+					die("Type::createInstance.InvalidTypeID");
+			}
+		}
+
+		return Variable(*this, value);
+	}
+
+
+#define fromType(type) Variable Variable::from##type(trainscript::type i) \
+	{ \
+		Variable var = Type::type.createInstance(); \
+		var.value<trainscript::type>() = i; \
+		return var; \
+	}
+
+	fromType(Int)
+	fromType(Real)
+	fromType(Text)
+	fromType(Bool)
+}

trainscript/variable.hpp

@@ -5,15 +5,66 @@
 
 namespace trainscript
 {
-	struct Variable
+	class Variable
 	{
-		Type type;
+		friend class Type;
-		union {
+	private:
-			Int integer;
+		Type mType;
-			Real real;
+		void *mValue;
-			// Text text;
+	private:
-			Bool boolean;
+		// To be called by Type::createInstance
-		};
+		Variable(const Type &type, void *value) :
+			mType(type),
+			mValue(value)
+		{
+
+		}
+	public:
+		Variable() :
+			mType(Type::Invalid),
+			mValue(nullptr)
+		{
+
+		}
+
+		Variable(const Variable &other) :
+			mType(other.mType),
+			mValue(nullptr)
+		{
+			*this = other;
+		}
+
+		Variable(Variable &&other) :
+			mType(other.mType),
+			mValue(other.mValue)
+		{
+			other.mType = Type::Invalid;
+			other.mValue = nullptr;
+		}
+		~Variable();
+
+		Variable &operator =(const Variable &other);
+
+		void *data() const
+		{
+			return this->mValue;
+		}
+
+		template<typename T>
+		T& value()
+		{
+			return *reinterpret_cast<T*>(this->mValue);
+		}
+
+		template<typename T>
+		const T& value() const
+		{
+			return *reinterpret_cast<T*>(this->mValue);
+		}
+
+		const Type &type() const {
+			return this->mType;
+		}
 
 #if defined(TSVM_PRINTVAL)
 		void printval() const
@@ -27,29 +78,16 @@ namespace trainscript
 		}
 #endif
 
+		static Variable fromInt(trainscript::Int i);
+		static Variable fromReal(trainscript::Real r);
+		static Variable fromText(trainscript::Text t);
+		static Variable fromBool(Bool b);
+
 		static const Variable Invalid;
 		static const Variable Void;
 		static const Variable Int;
 		static const Variable Real;
 		static const Variable Text;
-		static const Variable Boolean;
+		static const Variable Bool;
 	};
-
-	static inline Variable mkvar(Int value) {
-		Variable v = Variable::Int;
-		v.integer = value;
-		return v;
-	}
-
-	static inline Variable mkvar(Real value) {
-		Variable v = Variable::Real;
-		v.real = value;
-		return v;
-	}
-
-	static inline Variable mkbool(Bool value) {
-		Variable v = Variable::Boolean;
-		v.boolean = value;
-		return v;
-	}
 }