diff --git a/common/SC_AllocPool.cpp b/common/SC_AllocPool.cpp
index b10c91c5221..3ed832adc46 100644
--- a/common/SC_AllocPool.cpp
+++ b/common/SC_AllocPool.cpp
@@ -535,7 +535,7 @@ void* AllocPool::Realloc(void* inPtr, size_t inReqSize)
 void AllocPool::LinkFree(AllocChunkPtr inChunk)
 {
 	size_t size = inChunk->Size();
-	int index = BinIndex(size);
+	size_t index = BinIndex(size);
 
 	AllocChunkPtr bin = mBins + index;
 
diff --git a/include/common/SC_AllocPool.h b/include/common/SC_AllocPool.h
index b9cdf668d9c..c3f6ce19276 100644
--- a/include/common/SC_AllocPool.h
+++ b/include/common/SC_AllocPool.h
@@ -203,11 +203,11 @@ class AllocPool
 		return (bits << 3) + (inSize >> bits) ;
 	}
 
-	void MarkBinBlock(int inIndex)
+	void MarkBinBlock(size_t inIndex)
 		{
-			unsigned long word = inIndex >> 5;
-			unsigned long bitPosition = inIndex & 31;
-			unsigned long bitValue = 1L << bitPosition;
+			size_t word = inIndex >> 5;
+			size_t bitPosition = inIndex & 31;
+			size_t bitValue = 1L << bitPosition;
 			mBinBlocks[word] |= bitValue;
 		}
 
diff --git a/include/lang/ByteCodeArray.h b/include/lang/ByteCodeArray.h
index 5e23ed288fe..9cd1b3fbc4f 100644
--- a/include/lang/ByteCodeArray.h
+++ b/include/lang/ByteCodeArray.h
@@ -29,7 +29,7 @@ typedef unsigned char Byte;
 typedef struct {
 	Byte *bytes;
 	Byte *ptr;
-	long size;
+	size_t size;
 } ByteCodeArray, *ByteCodes;
 
 extern ByteCodes gCompilingByteCodes;
@@ -42,7 +42,7 @@ void copyByteCodes(Byte *dest, ByteCodes byteCodes);
 ByteCodes getByteCodes();
 ByteCodes saveByteCodeArray();
 void restoreByteCodeArray(ByteCodes byteCodes);
-int byteCodeLength(ByteCodes byteCodes);
+size_t byteCodeLength(ByteCodes byteCodes);
 void compileByteCodes(ByteCodes byteCodes);
 ByteCodes allocByteCodes();
 void reallocByteCodes(ByteCodes byteCodes);
diff --git a/lang/LangSource/ByteCodeArray.cpp b/lang/LangSource/ByteCodeArray.cpp
index 6b583a24f6e..80ff41e4c73 100644
--- a/lang/LangSource/ByteCodeArray.cpp
+++ b/lang/LangSource/ByteCodeArray.cpp
@@ -128,7 +128,7 @@ void restoreByteCodeArray(ByteCodes byteCodes)
 	gCompilingByteCodes = byteCodes;
 }
 
-int byteCodeLength(ByteCodes byteCodes)
+size_t byteCodeLength(ByteCodes byteCodes)
 {
     if (!byteCodes) return 0;
     return (byteCodes->ptr - byteCodes->bytes);
@@ -176,13 +176,12 @@ ByteCodes allocByteCodes()
 void reallocByteCodes(ByteCodes byteCodes)
 {
 	Byte		*newBytes;
-	int		newLen;
 
 	if (byteCodes->size != (byteCodes->ptr - byteCodes->bytes)) {
 		error("reallocByteCodes called with size != byteCode len");
 	}
 
-	newLen = byteCodes->size << 1;
+	size_t newLen = byteCodes->size << 1;
 	// pyrmalloc: I think that all bytecodes are copied to objects
 	// lifetime: kill after compile
 	newBytes = (Byte *)pyr_pool_compile->Alloc(newLen);
diff --git a/lang/LangSource/PyrInterpreter3.cpp b/lang/LangSource/PyrInterpreter3.cpp
index 88e6903c4e3..606625688e5 100644
--- a/lang/LangSource/PyrInterpreter3.cpp
+++ b/lang/LangSource/PyrInterpreter3.cpp
@@ -200,7 +200,7 @@ PyrProcess* newPyrProcess(VMGlobals *g, PyrClass *procclassobj)
 	}
 
 	PyrSymbol * contextsym = getsym("functionCompileContext");
-	int index = slotRawInt(&class_interpreter->classIndex) + contextsym->u.index;
+	size_t index = slotRawInt(&class_interpreter->classIndex) + contextsym->u.index;
 	PyrMethod * meth = gRowTable[index];
 	if (!meth || slotRawSymbol(&meth->name) != contextsym) {
 		error("compile context method 'functionCompileContext' not found.\n");
@@ -537,7 +537,8 @@ HOT void Interpret(VMGlobals *g)
 	// byte code values
 	unsigned char *ip;
 	unsigned char op1;
-	int op2, op3, index, tag;
+	size_t index;
+	int op2, op3, tag;
 	// interpreter globals
 
 	// temporary variables used in the interpreter
@@ -2754,7 +2755,6 @@ void DumpDetailedBackTrace(VMGlobals *g)
 
 void DumpStack(VMGlobals *g, PyrSlot *sp)
 {
-	int i;
 	PyrSlot *slot;
 	char str[128];
 #if BCSTAT
@@ -2763,7 +2763,7 @@ void DumpStack(VMGlobals *g, PyrSlot *sp)
 	postfl("STACK:\n");
 	slot = sp - 64;
 	if (slot < g->gc->Stack()->slots) slot = g->gc->Stack()->slots;
-	for (i=slot - g->gc->Stack()->slots; slot<=sp; slot++, ++i) {
+	for (size_t i=slot - g->gc->Stack()->slots; slot<=sp; slot++, ++i) {
 		slotString(slot, str);
 		post("   %2d  %s\n", i, str);
 	}