diff --git a/GNUmakefile b/GNUmakefile
index a8162f15..d7855da8 100755
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -176,6 +176,7 @@ endif
 endif
 
 # Tell MacPorts GCC to use Clang integrated assembler
+#   http://github.com/weidai11/cryptopp/issues/190
 ifeq ($(GCC_COMPILER)$(MACPORTS_COMPILER),11)
 ifneq ($(findstring -Wa,-q,$(CXXFLAGS)),-Wa,-q)
 CXXFLAGS += -Wa,-q
@@ -185,6 +186,12 @@ CXXFLAGS += -DCRYPTOPP_CLANG_INTEGRATED_ASSEMBLER=1
 endif
 endif
 
+# GCC on Solaris needs -m64. Otherwise, i386 is default
+#   http://github.com/weidai11/cryptopp/issues/230
+ifeq ($(IS_SUN)$(GCC_COMPILER)$(IS_X64),111)
+CXXFLAGS += -m64
+endif
+
 # Allow use of "/" operator for GNU Assembler.
 #   http://sourceware.org/bugzilla/show_bug.cgi?id=4572
 ifeq ($(findstring -DCRYPTOPP_DISABLE_ASM,$(CXXFLAGS)),)
diff --git a/misc.h b/misc.h
index 71e1cb51..e86f9ac3 100644
--- a/misc.h
+++ b/misc.h
@@ -702,7 +702,7 @@ inline unsigned int TrailingZeros(word64 v)
 	// We don't enable for Microsoft because it requires a runtime check.
 	// http://msdn.microsoft.com/en-us/library/hh977023%28v=vs.110%29.aspx
 	assert(v != 0);
-#if defined(__GNUC__) && defined(__BMI__)
+#if defined(__GNUC__) && defined(__BMI__) && defined(__x86_64__)
 	return (unsigned int)_tzcnt_u64(v);
 #elif defined(__GNUC__) && (CRYPTOPP_GCC_VERSION >= 30400)
 	return (unsigned int)__builtin_ctzll(v);
@@ -815,11 +815,13 @@ inline bool IsPowerOf2<word32>(const word32 &value)
 	return value > 0 && _blsr_u32(value) == 0;
 }
 
+# if defined(__x86_64__)
 template <>
 inline bool IsPowerOf2<word64>(const word64 &value)
 {
 	return value > 0 && _blsr_u64(value) == 0;
 }
+# endif
 #endif
 
 //! \brief Tests whether the residue of a value is a power of 2