M CHANGES → CHANGES

@@ -57,6 +57,7 @@ - Core: Ensure ELF regions can be written before trying
  - Core: Fix threading improperly setting paused state while interrupted
  - Debugger: Don't skip undefined instructions when debugger attached
  - Debugger: Close trace log when done tracing
+ - Debugger: Fix change watchpoints (fixes mgba.io/i/1947)
  - FFmpeg: Fix some small memory leaks
  - FFmpeg: Fix encoding of time base
  - GB Video: Fix SGB video logs

M include/mgba/debugger/debugger.h → include/mgba/debugger/debugger.h

@@ -38,7 +38,8 @@ enum mWatchpointType {
 	WATCHPOINT_WRITE = 1,
 	WATCHPOINT_READ = 2,
 	WATCHPOINT_RW = 3,
-	WATCHPOINT_WRITE_CHANGE = 4,
+	WATCHPOINT_CHANGE = 4,
+	WATCHPOINT_WRITE_CHANGE = 5,
 };
 
 enum mBreakpointType {

M src/arm/debugger/memory-debugger.c → src/arm/debugger/memory-debugger.c

@@ -106,17 +106,24 @@ return false;
 				}
 			}
 
+			uint32_t oldValue;
 			switch (width + 1) {
 			case 1:
-				info->type.wp.oldValue = debugger->originalMemory.load8(debugger->cpu, address, 0);
+				oldValue = debugger->originalMemory.load8(debugger->cpu, address, 0);
 				break;
 			case 2:
-				info->type.wp.oldValue = debugger->originalMemory.load16(debugger->cpu, address, 0);
+				oldValue = debugger->originalMemory.load16(debugger->cpu, address, 0);
 				break;
 			case 4:
-				info->type.wp.oldValue = debugger->originalMemory.load32(debugger->cpu, address, 0);
+				oldValue = debugger->originalMemory.load32(debugger->cpu, address, 0);
 				break;
+			default:
+				continue;
 			}
+			if ((watchpoint->type & WATCHPOINT_CHANGE) && newValue == oldValue) {
+				continue;
+			}
+			info->type.wp.oldValue = oldValue;
 			info->type.wp.newValue = newValue;
 			info->address = address;
 			info->type.wp.watchType = watchpoint->type;

M src/sm83/debugger/memory-debugger.c → src/sm83/debugger/memory-debugger.c

@@ -55,7 +55,11 @@ if (!mDebuggerEvaluateParseTree(debugger->d.p, watchpoint->condition, &value, &segment) || !(value || segment >= 0)) {
 					return false;
 				}
 			}
-			info->type.wp.oldValue = debugger->originalMemory.load8(debugger->cpu, address);
+			uint8_t oldValue = debugger->originalMemory.load8(debugger->cpu, address);
+			if ((watchpoint->type & WATCHPOINT_CHANGE) && newValue == oldValue) {
+				continue;
+			}
+			info->type.wp.oldValue = oldValue;
 			info->type.wp.newValue = newValue;
 			info->address = address;
 			info->type.wp.watchType = watchpoint->type;