Introduced enough logic that the Atari 2600 is being run, at least. No output yet though because (i) it has no-one to send output to; and (ii) there's nobody that knows how to display output. Hmmm.

OSBindings/Mac/Clock Signal/Atari2600Document.swift

@@ -8,15 +8,17 @@
 
 import Cocoa
 
-class Atari2600Document: NSDocument {
+class Atari2600Document: NSDocument, CSOpenGLViewDelegate {
 
 	override init() {
 	    super.init()
 		// Add your subclass-specific initialization here.
 	}
 
+	@IBOutlet weak var openGLView: CSOpenGLView?
 	override func windowControllerDidLoadNib(aController: NSWindowController) {
 		super.windowControllerDidLoadNib(aController)
+		openGLView!.delegate = self
 		// Add any code here that needs to be executed once the windowController has loaded the document's window.
 	}
 
@@ -45,5 +47,14 @@ class Atari2600Document: NSDocument {
 		atari2600?.setROM(data)
 	}
 
+	private var lastCycleCount: Int64?
+	func openGLView(view: CSOpenGLView!, didUpdateToTime time: CVTimeStamp) {
 
+		let cycleCount = (1194720 * time.videoTime) / Int64(time.videoTimeScale)
+		if let lastCycleCount = lastCycleCount {
+			let elapsedTime = cycleCount - lastCycleCount
+			atari2600!.runForNumberOfCycles(Int32(elapsedTime))
+		}
+		lastCycleCount = cycleCount
+	}
 }

OSBindings/Mac/Clock Signal/Base.lproj/Atari2600Document.xib

@@ -4,8 +4,9 @@
         <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="8152.3"/>
     </dependencies>
     <objects>
-        <customObject id="-2" userLabel="File's Owner" customClass="Document" customModule="Clock_Signal" customModuleProvider="target">
+        <customObject id="-2" userLabel="File's Owner" customClass="Atari2600Document" customModule="Clock_Signal" customModuleProvider="target">
             <connections>
+                <outlet property="openGLView" destination="DEG-fq-cjd" id="Gxs-2u-n7B"/>
                 <outlet property="window" destination="xOd-HO-29H" id="JIz-fz-R2o"/>
             </connections>
         </customObject>

OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h

@@ -3,3 +3,4 @@
 //
 
 #import "Atari2600.h"
+#import	"OpenGLView.h"

OSBindings/Mac/Clock Signal/OpenGLView.h

@@ -9,6 +9,14 @@
 #import <Foundation/Foundation.h>
 @import AppKit;
 
+@class CSOpenGLView;
+
+@protocol CSOpenGLViewDelegate
+- (void)openGLView:(CSOpenGLView *)view didUpdateToTime:(CVTimeStamp)time;
+@end
+
 @interface CSOpenGLView : NSOpenGLView
 
+@property (nonatomic, weak) id <CSOpenGLViewDelegate> delegate;
+
 @end

OSBindings/Mac/Clock Signal/OpenGLView.m

@@ -34,10 +34,10 @@
 	CVDisplayLinkStart(displayLink);
 }
 
-// This is the renderer output callback function
 static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp* now, const CVTimeStamp* outputTime, CVOptionFlags flagsIn, CVOptionFlags* flagsOut, void* displayLinkContext)
 {
-	[(__bridge CSOpenGLView *)displayLinkContext setNeedsDisplay:YES];
+	CSOpenGLView *view = (__bridge CSOpenGLView *)displayLinkContext;
+	[view.delegate openGLView:view didUpdateToTime:*now];
 	return kCVReturnSuccess;
 }