diff --git a/Makefile b/Makefile
index 4c604f9..0ee3263 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,26 @@
+# detect OS
+ifeq ($(OS),Windows_NT)
+    RM = del /q
+else
+    UNAME_S := $(shell uname -s)
+    ifeq ($(UNAME_S),Linux)
+        RM = rm -rf
+    endif
+    ifeq ($(UNAME_S),Darwin)
+        RM = rm -rf
+    endif
+    # UNAME_P := $(shell uname -p)
+    # ifeq ($(UNAME_P),x86_64)
+    #     CCFLAGS += -D AMD64
+    # endif
+    # ifneq ($(filter %86,$(UNAME_P)),)
+    #     CCFLAGS += -D IA32
+    # endif
+    # ifneq ($(filter arm%,$(UNAME_P)),)
+    #     CCFLAGS += -D ARM
+    # endif
+endif
+
 # set CC TOOL
 CC := sdcc
 PACKIHX := packihx
@@ -19,7 +42,7 @@ OBJ := $(patsubst src/%.c, obj/%.rel, $(SRC))
 all: uart_temp.hex
 
 clean:
-	-del /q obj\*
+	-$(RM) obj\*
 
 $(OBJ):obj/%.rel:src/%.c
 	-$(CC) $(CFLAGS) -I $(INC) -c $^ -o $@