diff --git a/include/c64/rasterirq.c b/include/c64/rasterirq.c
index e9783d0..55ab464 100644
--- a/include/c64/rasterirq.c
+++ b/include/c64/rasterirq.c
@@ -593,8 +593,18 @@ void rirq_sort(void)
 		rasterIRQIndex[j] = ri;
 	}
 #endif
+
+#if NUM_IRQS & 3
 	for(sbyte i=NUM_IRQS-1; i>=0; i--)
 		rasterIRQNext[i] = rasterIRQRows[rasterIRQIndex[i + 1]];
+#else
+	for(sbyte i=NUM_IRQS/4-1; i>=0; i--)
+	{
+		#pragma unroll(full)
+		for(int j=0; j<4; j++)
+			rasterIRQNext[i + j * NUM_IRQS / 4] = rasterIRQRows[rasterIRQIndex[i + j * NUM_IRQS / 4 + 1]];
+	}
+#endif
 
 	npos++;
 	byte	yp = rasterIRQNext[nextIRQ];
diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index 2195fd6..5a9c891 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -11414,6 +11414,10 @@ NativeCodeBasicBlock* NativeCodeBasicBlock::BinaryOperator(InterCodeProcedure* p
 					}
 					else
 					{
+						uint32	mask = 0xffff;
+						if (ins->mSrc[1].IsPositive() && ins->mSrc[1].mRange.mMaxState == IntegerValueRange::S_BOUND)
+							mask = uint32(ins->mSrc[1].mRange.mMaxValue);
+
 						if (ins->mSrc[1].mTemp != ins->mDst.mTemp)
 						{
 							mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ZERO_PAGE, BC_REG_TMP + proc->mTempOffset[ins->mSrc[1].mTemp] + 1));
@@ -11429,8 +11433,14 @@ NativeCodeBasicBlock* NativeCodeBasicBlock::BinaryOperator(InterCodeProcedure* p
 						mIns.Push(NativeCodeInstruction(ins, ASMIT_ROR, ASMIM_IMPLIED));
 						for (int i = 1; i < shift; i++)
 						{
-							mIns.Push(NativeCodeInstruction(ins, ASMIT_LSR, ASMIM_ZERO_PAGE, treg + 1));
-							mIns.Push(NativeCodeInstruction(ins, ASMIT_ROR, ASMIM_IMPLIED));
+							mask >>= 1;
+							if (mask > 0xff)
+							{
+								mIns.Push(NativeCodeInstruction(ins, ASMIT_LSR, ASMIM_ZERO_PAGE, treg + 1));
+								mIns.Push(NativeCodeInstruction(ins, ASMIT_ROR, ASMIM_IMPLIED));
+							}
+							else
+								mIns.Push(NativeCodeInstruction(ins, ASMIT_LSR, ASMIM_IMPLIED));
 						}
 						mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg));
 					}
diff --git a/oscar64/oscar64.cpp b/oscar64/oscar64.cpp
index af9f463..a28de03 100644
--- a/oscar64/oscar64.cpp
+++ b/oscar64/oscar64.cpp
@@ -120,14 +120,14 @@ int main2(int argc, const char** argv)
 			strcpy_s(crtFileNamePath, basePath);
 			strcat_s(crtFileNamePath, "include/crt.h");
 
-			if ((crtFile = fopen(crtFileNamePath, "r")))
+			if (!fopen_s(&crtFile, crtFileNamePath, "r"))
 				strcat_s(includePath, "include/");
 			else
 			{
 				strcpy_s(crtFileNamePath, basePath);
 				strcat_s(crtFileNamePath, "include/oscar64/crt.h");
 
-				if ((crtFile = fopen(crtFileNamePath, "r")))
+				if (!fopen_s(&crtFile, crtFileNamePath, "r"))
 					strcat_s(includePath, "include/oscar64/");
 				else
 				{