diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib b/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib
index c05cc35cd..50926faf4 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Options.xib	
@@ -12,7 +12,7 @@
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
         <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="gsl-7V-TTU" customClass="Atari2600OptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
-            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" HUD="YES"/>
+            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES" HUD="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="83" y="102" width="200" height="121"/>
             <rect key="screenRect" x="0.0" y="0.0" width="1366" height="768"/>
diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/ElectronOptions.xib b/OSBindings/Mac/Clock Signal/Base.lproj/ElectronOptions.xib
index 39521bbd1..20ebefd9a 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/ElectronOptions.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/ElectronOptions.xib	
@@ -12,7 +12,7 @@
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
         <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="ZW7-Bw-4RP" customClass="ElectronOptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
-            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" HUD="YES"/>
+            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES" HUD="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="83" y="102" width="200" height="83"/>
             <rect key="screenRect" x="0.0" y="0.0" width="1366" height="768"/>
diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/Vic20Options.xib b/OSBindings/Mac/Clock Signal/Base.lproj/Vic20Options.xib
index 4c477e080..2284abe76 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/Vic20Options.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/Vic20Options.xib	
@@ -12,7 +12,7 @@
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
         <window title="Options" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" hidesOnDeactivate="YES" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" frameAutosaveName="" animationBehavior="default" id="ota-g7-hOL" customClass="Vic20OptionsPanel" customModule="Clock_Signal" customModuleProvider="target">
-            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" HUD="YES"/>
+            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES" HUD="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="83" y="102" width="200" height="134"/>
             <rect key="screenRect" x="0.0" y="0.0" width="1366" height="768"/>
diff --git a/OSBindings/Mac/Clock SignalTests/DPLLTests.swift b/OSBindings/Mac/Clock SignalTests/DPLLTests.swift
index 366b39da2..67113b928 100644
--- a/OSBindings/Mac/Clock SignalTests/DPLLTests.swift	
+++ b/OSBindings/Mac/Clock SignalTests/DPLLTests.swift	
@@ -56,6 +56,6 @@ class DPLLTests: XCTestCase {
 		}
 
 		let endOfStream = (pll?.stream)!&0xffffffff;
-		XCTAssert(endOfStream == 0xaaaaaaaa || endOfStream == 0x55555555, "PLL should have synchronised and clocked repeating 0xa or 0x5 nibbles; got \(String(pll?.stream, radix: 16, uppercase: false))")
+		XCTAssert(endOfStream == 0xaaaaaaaa || endOfStream == 0x55555555, "PLL should have synchronised and clocked repeating 0xa or 0x5 nibbles; got \(String(pll!.stream, radix: 16, uppercase: false))")
 	}
 }
diff --git a/OSBindings/Mac/Clock SignalTests/WolfgangLorenzTests.swift b/OSBindings/Mac/Clock SignalTests/WolfgangLorenzTests.swift
index 8bd25ecc3..e30dae422 100644
--- a/OSBindings/Mac/Clock SignalTests/WolfgangLorenzTests.swift	
+++ b/OSBindings/Mac/Clock SignalTests/WolfgangLorenzTests.swift	
@@ -208,7 +208,7 @@ class WolfgangLorenzTests: XCTestCase, CSTestMachineJamHandler {
 
 				let dataPointer = (testData as NSData).bytes.bindMemory(to: UInt8.self, capacity: testData.count)
 				let loadAddress = UInt16(dataPointer[0]) | (UInt16(dataPointer[1]) << 8)
-				let contents = testData.subdata(in: NSMakeRange(2, testData.count - 2))
+				let contents = testData.subdata(in: 2..<(testData.count - 2))
 
 				machine.setData(contents, atAddress: loadAddress)
 
diff --git a/Processors/6502/CPU6502.hpp b/Processors/6502/CPU6502.hpp
index baa2a5882..1d2f3e977 100644
--- a/Processors/6502/CPU6502.hpp
+++ b/Processors/6502/CPU6502.hpp
@@ -833,25 +833,22 @@ template <class T> class Processor {
 						case OperationADC:
 							if(_decimalFlag) {
 								const uint16_t decimalResult = (uint16_t)_a + (uint16_t)_operand + (uint16_t)_carryFlag;
-								uint16_t temp16;
 
-								temp16 = (_a&0xf) + (_operand&0xf) + _carryFlag;
-								if(temp16 > 0x9) temp16 += 0x6;
-								temp16 = (temp16&0x0f) + ((temp16 > 0x0f) ? 0x10 : 0x00) + (_a&0xf0) + (_operand&0xf0);
+								uint8_t low_nibble = (_a & 0xf) + (_operand & 0xf) + _carryFlag;
+								if(low_nibble >= 0xa) low_nibble = ((low_nibble + 0x6) & 0xf) + 0x10;
+								uint16_t result = (uint16_t)(_a & 0xf0) + (uint16_t)(_operand & 0xf0) + (uint16_t)low_nibble;
+								_negativeResult = (uint8_t)result;
+								_overflowFlag =  (( (result^_a)&(result^_operand) )&0x80) >> 1;
+								if(result >= 0xa0) result += 0x60;
 
-								_overflowFlag =  (( (decimalResult^_a)&(decimalResult^_operand) )&0x80) >> 1;
-								_negativeResult = (uint8_t)temp16;
+								_carryFlag = (result >> 8) ? 1 : 0;
+								_a = (uint8_t)result;
 								_zeroResult = (uint8_t)decimalResult;
-
-								if(temp16 > 0x9f) temp16 += 0x60;
-
-								_carryFlag = (temp16 > 0xff) ? Flag::Carry : 0;
-								_a = (uint8_t)temp16;
 							} else {
-								const uint16_t decimalResult = (uint16_t)_a + (uint16_t)_operand + (uint16_t)_carryFlag;
-								_overflowFlag =  (( (decimalResult^_a)&(decimalResult^_operand) )&0x80) >> 1;
-								_negativeResult = _zeroResult = _a = (uint8_t)decimalResult;
-								_carryFlag = (decimalResult >> 8)&1;
+								const uint16_t result = (uint16_t)_a + (uint16_t)_operand + (uint16_t)_carryFlag;
+								_overflowFlag =  (( (result^_a)&(result^_operand) )&0x80) >> 1;
+								_negativeResult = _zeroResult = _a = (uint8_t)result;
+								_carryFlag = (result >> 8)&1;
 							}
 
 							// fix up in case this was INS