diff --git a/GNUmakefile-cross b/GNUmakefile-cross
index ba4b7174..16140b41 100755
--- a/GNUmakefile-cross
+++ b/GNUmakefile-cross
@@ -251,6 +251,7 @@ ifeq ($(IS_ARMv7),1)
     GCM_FLAG = -march=armv7-a
     ARIA_FLAG = -march=armv7-a
     BLAKE2_FLAG = -march=armv7-a
+    CHACHA_FLAG = -march=armv7-a
     LEA_FLAG = -march=armv7-a
   endif
 endif
@@ -262,6 +263,7 @@ ifeq ($(IS_NEON),1)
     GCM_FLAG += -mfpu=neon
     ARIA_FLAG += -mfpu=neon
     BLAKE2_FLAG += -mfpu=neon
+    CHACHA_FLAG += -mfpu=neon
     LEA_FLAG += -mfpu=neon
     SIMECK_FLAG += -mfpu=neon
     SIMON64_FLAG += -mfpu=neon
@@ -274,6 +276,7 @@ ifeq ($(IS_NEON),1)
         GCM_FLAG += -mfloat-abi=softfp
         ARIA_FLAG += -mfloat-abi=softfp
         BLAKE2_FLAG += -mfloat-abi=softfp
+        CHACHA_FLAG += -mfloat-abi=softfp
         LEA_FLAG += -mfloat-abi=softfp
         SIMECK_FLAG += -mfloat-abi=softfp
         SIMON64_FLAG += -mfloat-abi=softfp
@@ -291,6 +294,7 @@ ifneq ($(IS_ARMv8),0)
   ifeq ($(IS_NEON),1)
     ARIA_FLAG = -march=armv8-a
     BLAKE2_FLAG = -march=armv8-a
+	CHACHA_FLAG = -march=armv8-a
     LEA_FLAG = -march=armv8-a
     NEON_FLAG = -march=armv8-a
     SIMECK_FLAG = -march=armv8-a
@@ -317,6 +321,11 @@ endif
 
 # i686 and x86_64
 ifneq ($(IS_i686)$(IS_x86_64),00)
+# SSE2 is a core feature of x86_64
+ifeq ($(findstring -DCRYPTOPP_DISABLE_ASM,$(CXXFLAGS)),)
+  SSE_FLAG = -msse2
+  CHACHA_FLAG = -msse2
+endif
   HAVE_SSSE3 = $(shell $(CXX) $(CXXFLAGS) -DADHOC_MAIN -mssse3 -dM -E adhoc.cpp 2>&1 |  $(EGREP) -i -c __SSSE3__)
   ifeq ($(HAVE_SSSE3),1)
     ARIA_FLAG = -mssse3
@@ -570,6 +579,10 @@ aria-simd.o : aria-simd.cpp
 blake2-simd.o : blake2-simd.cpp
 	$(CXX) $(strip $(CXXFLAGS) $(BLAKE2_FLAG) -c) $<
 
+# SSE2 or NEON available
+chacha-simd.o : chacha-simd.cpp
+	$(CXX) $(strip $(CXXFLAGS) $(CHACHA_FLAG) -c) $<
+
 # SSSE3 available
 cham-simd.o : cham-simd.cpp
 	$(CXX) $(strip $(CXXFLAGS) $(CHAM_FLAG) -c) $<