diff --git a/Makefile b/Makefile
index 38533e5..01438b9 100644
--- a/Makefile
+++ b/Makefile
@@ -12,10 +12,14 @@ ifeq ($(sse2only),) # if sse2only is not defined
 else                # if sse2only is defined
 	OBJS+=ksw2_extz2_sse.o ksw2_extd2_sse.o ksw2_exts2_sse.o
 endif
-else                # if arm_neon is defined
-    OBJS+=ksw2_extz2_neon.o ksw2_extd2_neon.o ksw2_exts2_neon.o
-    CFLAGS+=-D_FILE_OFFSET_BITS=64 -mfpu=neon -fsigned-char
+else				# if arm_neon is defined
+	OBJS+=ksw2_extz2_neon.o ksw2_extd2_neon.o ksw2_exts2_neon.o
     INCLUDES+=-Isse2neon
+ifeq ($(aarch64),)	#if aarch64 is not defined
+	CFLAGS+=-D_FILE_OFFSET_BITS=64 -mfpu=neon -fsigned-char
+else				#if aarch64 is defined
+	CFLAGS+=-D_FILE_OFFSET_BITS=64 -fsigned-char
+endif	
 endif
 
 .PHONY:all extra clean depend
diff --git a/README.md b/README.md
index 1a0dc9e..8ce319d 100644
--- a/README.md
+++ b/README.md
@@ -78,7 +78,7 @@ directory to compile. If you see compilation errors, try `make sse2only=1`
 to disable SSE4 code, which will make minimap2 slightly slower.
 
 Minimap2 also works with ARM CPUs supporting the NEON instruction sets. To
-compile, use `make arm_neon=1`.
+compile for 32 bit ARM architectures (such as ARMv7), use `make arm_neon=1`. To compile for for 64 bit ARM architectures (such as ARMv8), use `make arm_neon=1 aarch64=1`.
 
 ### <a name="general"></a>General usage