diff --git a/sim/common/xlen.h b/sim/common/xlen.h
index 9af483b5..07a75b96 100644
--- a/sim/common/xlen.h
+++ b/sim/common/xlen.h
@@ -5,7 +5,7 @@
 #endif
 
 #ifndef FLEN
-#define FLEN 32
+#define FLEN XLEN
 #endif
 
 #if XLEN == 32
diff --git a/tests/runtime/simple/Makefile b/tests/runtime/simple/Makefile
index 51163385..5cb7a278 100644
--- a/tests/runtime/simple/Makefile
+++ b/tests/runtime/simple/Makefile
@@ -27,7 +27,7 @@ LDFLAGS += -lm -Wl,-Bstatic,-T,$(VORTEX_RT_PATH)/linker/vx_link$(XLEN).ld -Wl,--
 
 PROJECT = simple
 
-SRCS = main.cpp
+SRCS = main.cpp tests.cpp
 
 all: $(PROJECT).elf $(PROJECT).bin $(PROJECT).dump