diff --git a/toolbox/mm.cpp b/toolbox/mm.cpp
index dc99775..4998880 100644
--- a/toolbox/mm.cpp
+++ b/toolbox/mm.cpp
@@ -124,6 +124,27 @@ namespace MM
 		return 0;
 	}
 
+
+	uint32_t CompactMem(uint16_t trap)
+	{
+		// todo -- add function to check pool for largest block?
+
+		/* 
+		 * on entry:
+		 * D0: cbNeeded (long word)
+		 *
+		 * on exit:
+		 * D0: function result (long word)
+		 *
+		 */
+		 uint32_t cbNeeded = cpuGetDReg(0);
+
+		 fprintf(stderr, "%04x CompactMem(%08x)\n", trap, cbNeeded);
+		 
+		 return 0x0f0000;
+	}
+
+
 	uint16_t DisposePtr(uint16_t trap)
 	{
 		/* 
diff --git a/toolbox/mm.h b/toolbox/mm.h
index 77d3cfc..88870ff 100644
--- a/toolbox/mm.h
+++ b/toolbox/mm.h
@@ -14,6 +14,7 @@ namespace MM
 	bool Init(uint8_t *memory, uint32_t memorySize, uint32_t reserved);
 
 	uint16_t BlockMove(uint16_t trap);
+	uint32_t CompactMem(uint16_t trap);
 	uint16_t DisposePtr(uint16_t trap);
 	uint16_t DisposeHandle(uint16_t trap);
 
@@ -21,4 +22,6 @@ namespace MM
 	uint16_t NewHandle(uint16_t trap);
 }
 
+
+
 #endif
\ No newline at end of file
diff --git a/toolbox/toolbox.cpp b/toolbox/toolbox.cpp
index c0bf330..f31b900 100644
--- a/toolbox/toolbox.cpp
+++ b/toolbox/toolbox.cpp
@@ -58,6 +58,11 @@ namespace ToolBox {
 				d0 = MM::BlockMove(trap);
 				break;
 
+			// CompactMem (cbNeeded: Size) : Size;
+			case 0xa04c:
+				d0 = MM::CompactMem(trap);
+				break;
+
 
 			// ReadDateTime (VAR sees: LONGINT) : OSErr;
 			case 0xa039: