malloc tools for VM

Author: Robert Lindner

Programs/DynamicAlloc/DynAlloc.bca

@@ -0,0 +1,35 @@
+LITERAL 15
+ALLOC
+LITERAL #a
+STORE
+
+LITERAL 8
+ALLOC
+LITERAL #b
+STORE
+
+LITERAL #a
+LOAD
+FREE
+
+LITERAL 5
+ALLOC
+LITERAL #a
+STORE
+
+LITERAL 7
+ALLOC
+LITERAL #c
+STORE
+
+LITERAL #b
+LOAD
+FREE
+
+LITERAL #a
+LOAD
+FREE
+
+LITERAL #c
+LOAD
+FREE

build/genie.lua

@@ -27,7 +27,7 @@ project "Bytecode"
         objdir "obj/debug"
         defines { "_DEBUG" }
         flags { "Symbols" }
-		debugargs { "cRun", "./Programs/Functions/Functions.bca" }
+		debugargs { "cRun", "./Programs/DynamicAlloc/DynAlloc.bca" }
     configuration "Release"
         targetdir "../bin/release/"
         objdir "obj/debug"

source/VirtualMachine.cpp

@@ -67,7 +67,11 @@ void VirtualMachine::SetProgram(std::vector<uint8> bytecode)
 	m_HeapBase = m_FirstSegmentPtr+sizeof(uint32);
 	Pack<uint32>(m_FirstSegmentPtr, m_HeapBase);
 	Pack<uint32>(m_HeapBase, MAX_RAM - m_HeapBase);
-	Pack<uint32>(m_HeapBase+sizeof(uint32), 0);
+	Pack<uint32>(m_HeapBase + sizeof(uint32), 0);
+
+	#ifdef VM_DEBUG_HEAP
+		PrintHeap();
+	#endif
 
     ProgramLoaded = true;
 }
@@ -87,7 +91,7 @@ void VirtualMachine::Interpret()
 
         Opcode operation = static_cast<Opcode>(m_RAM[m_ProgramCounter]);
 
-		//std::cout << "[DBG] operation: " << GetOpString(operation) << std::endl;
+		std::cout << "[DBG] operation: " << GetOpString(operation) << std::endl;
 
         switch(operation)
         {
@@ -200,6 +204,11 @@ void VirtualMachine::Interpret()
 					Pack<uint32>(prevNextPtr, Unpack<uint32>(bestFitPtr+sizeof(uint32)));//Link the previous segment to next segment
 				}
 				Push(bestFitPtr+sizeof(uint32));
+                ++m_ProgramCounter;
+
+				#ifdef VM_DEBUG_HEAP
+					PrintHeap();
+				#endif
             }
             continue;
             //Mark the space at (a) as unused
@@ -210,7 +219,7 @@ void VirtualMachine::Interpret()
 
 				uint32 existingNextPtr = m_FirstSegmentPtr;
 				uint32 nextSegment = Unpack<uint32>(existingNextPtr);
-				uint32 existingSegment;
+				uint32 existingSegment = existingNextPtr;
 
 				bool earlyOut = false;
 				while (nextSegment != 0 && !earlyOut)
@@ -219,7 +228,7 @@ void VirtualMachine::Interpret()
 					{
 						//insert
 						bool standalone = true;
-						if ((existingNextPtr != m_FirstSegmentPtr) && (existingSegment + Unpack<uint32>(existingSegment) == segmentPtr))//Merge EXISTING+INSERTED
+						if ((nextSegment != m_FirstSegmentPtr) && (existingSegment + Unpack<uint32>(existingSegment) == segmentPtr))//Merge EXISTING+INSERTED
 						{
 							//simply expand the existing segment to accomodate our size
 							segmentPtr = existingSegment;
@@ -248,7 +257,13 @@ void VirtualMachine::Interpret()
 				if (!earlyOut)
 				{
 					std::cerr << "[VM] Failed to free memory at " << segmentPtr << "; " << segmentSize << " bytes" << std::endl;
+					return;
 				}
+                ++m_ProgramCounter;
+
+				#ifdef VM_DEBUG_HEAP
+					PrintHeap();
+				#endif
             }
             continue;
 
@@ -464,3 +479,18 @@ void VirtualMachine::Pack(uint32 address, T value)
    m_RAM[address+3] = n & 0xFF;
 #endif
 }
+
+void VirtualMachine::PrintHeap(bool baseOffset)
+{
+	uint32 offset = baseOffset ? m_HeapBase : 0;
+	uint32 nextSegment = Unpack<uint32>(m_FirstSegmentPtr);
+
+	std::cout << "[DBG Heap]: "<< m_FirstSegmentPtr-offset << " first: " << nextSegment-offset << " \t";
+	while (nextSegment != 0)
+	{
+		std::cout << "@" << nextSegment-offset << "{s: " << Unpack<uint32>(nextSegment);
+		nextSegment = Unpack<uint32>(nextSegment + sizeof(uint32));
+		std::cout << "; n: " << nextSegment-offset << "} ";
+	}
+	std::cout << std::endl;
+}

source/VirtualMachine.h

@@ -5,6 +5,8 @@
 
 #include "AtomicTypes.h"
 
+#define VM_DEBUG_HEAP
+
 class VirtualMachine
 {
 public:
@@ -29,6 +31,8 @@ class VirtualMachine
     template<typename T>
     void Pack(uint32 address, T value);
 
+	void PrintHeap(bool baseOffset = false);
+
 private:
     //Static Sizes
     static const uint32 MAX_RAM = 536870912; //500 MB