diff --git a/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm b/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm
index 4fa46dce5..09d2fd40d 100644
--- a/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/68000ComparativeTests.mm	
@@ -17,19 +17,47 @@
 @interface M68000ComparativeTests : XCTestCase
 @end
 
-@implementation M68000ComparativeTests
+@implementation M68000ComparativeTests {
+	NSSet<NSString *> *_fileSet;
+	NSSet<NSString *> *_testSet;
+
+	NSMutableSet<NSString *> *_failures;
+	NSMutableArray<NSNumber *> *_failingOpcodes;
+}
+
+- (void)setUp {
+	// To limit tests run to a subset of files and/or of tests, uncomment and fill in below.
+//	_fileSet = [NSSet setWithArray:@[@"eor.json"]];
+//	_testSet = [NSSet setWithArray:@[@"EOR b0c0", @"EOR b0c2", @"EOR b0c3", @"EOR b0c5", @"EOR b0c6", @"EOR b0c7", @"OR b0c7"]];
+}
 
 - (void)testAll {
+	// These will accumulate a list of failing tests and associated opcodes.
+	_failures = [[NSMutableSet alloc] init];
+	_failingOpcodes = [[NSMutableArray alloc] init];
+
+	// Get the full list of available test files.
 	NSBundle *const bundle = [NSBundle bundleForClass:[self class]];
 	NSArray<NSURL *> *const tests = [bundle URLsForResourcesWithExtension:@"json" subdirectory:@"68000 Comparative Tests"];
 
+	// Issue each test file.
 	for(NSURL *url in tests) {
+		// Compare against a file set if one has been supplied.
+		if(_fileSet && ![_fileSet containsObject:[[url path] lastPathComponent]]) continue;
 		NSLog(@"Testing %@", url);
 		[self testJSONAtURL:url];
 	}
+
+	// Output a summary of failures.
+	NSLog(@"Failures: %@", _failures);
+	NSLog(@"Failing opcodes:");
+	for(NSNumber *number in _failingOpcodes) {
+		NSLog(@"%04x", number.intValue);
+	}
 }
 
 - (void)testJSONAtURL:(NSURL *)url {
+	// Read the nominated file and parse it as JSON.
 	NSData *const data = [NSData dataWithContentsOfURL:url];
 	NSError *error;
 	NSArray *const jsonContents = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
@@ -38,6 +66,7 @@
 		return;
 	}
 
+	// Perform each dictionary in the array as a test.
 	for(NSDictionary *test in jsonContents) {
 		if(![test isKindOfClass:[NSDictionary class]]) continue;
 		[self testOperation:test];
@@ -49,7 +78,8 @@
 	NSString *const name = test[@"name"];
 	if(!name) return;
 
-//	if(![name isEqualToString:@"ORI 7c"]) return;
+	// Compare against a test set if one has been supplied.
+	if(_testSet && ![_testSet containsObject:name]) return;
 
 	// This is the test class for 68000 execution.
 	struct Test68000: public CPU::MC68000::BusHandler {
@@ -126,11 +156,18 @@
 			const NSString *dX = [@"d" stringByAppendingFormat:@"%d", c];
 			const NSString *aX = [@"a" stringByAppendingFormat:@"%d", c];
 
+			if(state.data[c] != [finalState[dX] integerValue]) [_failures addObject:name];
+			if(c < 7 && state.address[c] != [finalState[aX] integerValue]) [_failures addObject:name];
+
 			XCTAssertEqual(state.data[c], [finalState[dX] integerValue], @"%@: D%d inconsistent", name, c);
 			if(c < 7) {
 				XCTAssertEqual(state.address[c], [finalState[aX] integerValue], @"%@: A%d inconsistent", name, c);
 			}
 		}
+		if(state.supervisor_stack_pointer != [finalState[@"a7"] integerValue]) [_failures addObject:name];
+		if(state.user_stack_pointer != [finalState[@"usp"] integerValue]) [_failures addObject:name];
+		if(state.status != [finalState[@"sr"] integerValue]) [_failures addObject:name];
+
 		XCTAssertEqual(state.supervisor_stack_pointer, [finalState[@"a7"] integerValue], @"%@: A7 inconsistent", name);
 		XCTAssertEqual(state.user_stack_pointer, [finalState[@"usp"] integerValue], @"%@: USP inconsistent", name);
 		XCTAssertEqual(state.status, [finalState[@"sr"] integerValue], @"%@: Status inconsistent", name);
@@ -144,6 +181,12 @@
 
 			if(!address || !value) break;
 			XCTAssertEqual(test68000->ram[address.integerValue ^ 1], value.integerValue, @"%@: Memory at location %@ inconsistent", name, address);
+			if(test68000->ram[address.integerValue ^ 1] != value.integerValue) [_failures addObject:name];
+		}
+
+		// Consider collating extra detail.
+		if([_failures containsObject:name]) {
+			[_failingOpcodes addObject:@((test68000->ram[0x100] << 8) | test68000->ram[0x101])];
 		}
 	};