diff --git a/nemu/configs/defconfig b/nemu/configs/defconfig
new file mode 100644
index 0000000..aa26803
--- /dev/null
+++ b/nemu/configs/defconfig
@@ -0,0 +1,74 @@
+#
+# Automatically generated file; DO NOT EDIT.
+# NEMU Configuration Menu
+#
+# CONFIG_ISA_x86 is not set
+# CONFIG_ISA_mips32 is not set
+CONFIG_ISA_riscv=y
+# CONFIG_ISA_loongarch32r is not set
+CONFIG_ISA="riscv32"
+
+#
+# ISA-dependent Options for riscv
+#
+# CONFIG_RV64 is not set
+# CONFIG_RVE is not set
+# end of ISA-dependent Options for riscv
+
+CONFIG_ENGINE_INTERPRETER=y
+CONFIG_ENGINE="interpreter"
+CONFIG_MODE_SYSTEM=y
+CONFIG_TARGET_NATIVE_ELF=y
+# CONFIG_TARGET_SHARE is not set
+# CONFIG_TARGET_AM is not set
+
+#
+# Build Options
+#
+CONFIG_CC_GCC=y
+# CONFIG_CC_GPP is not set
+# CONFIG_CC_CLANG is not set
+CONFIG_CC="gcc"
+# CONFIG_CC_O0 is not set
+# CONFIG_CC_O1 is not set
+CONFIG_CC_O2=y
+# CONFIG_CC_O3 is not set
+CONFIG_CC_OPT="-O2"
+# CONFIG_CC_LTO is not set
+# CONFIG_CC_DEBUG is not set
+CONFIG_CC_ASAN=y
+# end of Build Options
+
+#
+# Testing and Debugging
+#
+CONFIG_TRACE=y
+CONFIG_TRACE_START=0
+CONFIG_TRACE_END=10000
+CONFIG_ITRACE=y
+CONFIG_ITRACE_COND="true"
+# CONFIG_DIFFTEST is not set
+CONFIG_DIFFTEST_REF_PATH="none"
+CONFIG_DIFFTEST_REF_NAME="none"
+# end of Testing and Debugging
+
+#
+# Memory Configuration
+#
+CONFIG_MBASE=0x80000000
+CONFIG_MSIZE=0x8000000
+CONFIG_PC_RESET_OFFSET=0
+# CONFIG_PMEM_MALLOC is not set
+CONFIG_PMEM_GARRAY=y
+CONFIG_MEM_RANDOM=y
+# end of Memory Configuration
+
+# CONFIG_DEVICE is not set
+
+#
+# Miscellaneous
+#
+CONFIG_TIMER_GETTIMEOFDAY=y
+# CONFIG_TIMER_CLOCK_GETTIME is not set
+CONFIG_RT_CHECK=y
+# end of Miscellaneous
diff --git a/nemu/flake.nix b/nemu/flake.nix
index 47bb216..64632c6 100644
--- a/nemu/flake.nix
+++ b/nemu/flake.nix
@@ -50,6 +50,15 @@
             libllvm
           ];
 
+          bulidPhase = ''
+            make defconfig
+            make app
+          '';
+
+          installPhase = ''
+            cp 
+          '';
+
           NEMU_HOME = src;
 
           meta = with lib; {
diff --git a/nemu/scripts/build.mk b/nemu/scripts/build.mk
index b3ba734..55edd75 100644
--- a/nemu/scripts/build.mk
+++ b/nemu/scripts/build.mk
@@ -67,7 +67,7 @@ $(OBJ_DIR)/%.yy.o: $(OBJ_DIR)/%.yy.c
 
 # Some convenient rules
 
-.PHONY: app clean
+.PHONY: app install clean
 
 app: $(BINARY)
 
@@ -75,5 +75,9 @@ $(BINARY):: $(OBJS) $(ARCHIVES)
 	@echo + LD $@
 	@$(LD) -o $@ $(OBJS) $(LDFLAGS) $(ARCHIVES) $(LIBS)
 
+install: $(BINARY)
+	@mkdir -p $(PREFIX)/bin
+	@cp $(BINARY) $(PREFIX)/bin/
+
 clean:
 	-rm -rf $(BUILD_DIR)
diff --git a/nemu/src/monitor/sdb/addrexp.y b/nemu/src/monitor/sdb/addrexp.y
index 43d6c35..9e296ba 100644
--- a/nemu/src/monitor/sdb/addrexp.y
+++ b/nemu/src/monitor/sdb/addrexp.y
@@ -1,4 +1,4 @@
-%code requires { 
+%code requires {
     #include <common.h>
     #include <stdio.h>
     #include <stdlib.h>