diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e887775fe..2484b3ad9 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -357,19 +357,19 @@ if( NOT NO_ASM )
 			set( ASM_FLAGS -f win32 -DWIN32 -i${CMAKE_CURRENT_SOURCE_DIR}/ )
 		endif( X64 )
 	endif( UNIX )
-	if( WIN32 )
+	if( WIN32 AND NOT X64 )
 		set( FIXRTEXT fixrtext )
-	else( WIN32 )
+	else( WIN32 AND NOT X64 )
 		set( FIXRTEXT "" )
-	endif( WIN32 )
+	endif( WIN32 AND NOT X64 )
 	message( STATUS "Selected assembler: ${ASSEMBLER}" )
 	MACRO( ADD_ASM_FILE indir infile )
 		set( ASM_OUTPUT_${infile} "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/zdoom.dir/${indir}/${infile}${ASM_OUTPUT_EXTENSION}" )
-		if( WIN32 )
+		if( WIN32 AND NOT X64 )
 			set( FIXRTEXT_${infile} COMMAND ${FIXRTEXT} "${ASM_OUTPUT_${infile}}" )
-		else( WIN32 )
+		else( WIN32 AND NOT X64 )
 			set( FIXRTEXT_${infile} COMMAND "" )
-		endif( WIN32 )
+		endif( WIN32 AND NOT X64 )
 		add_custom_command( OUTPUT ${ASM_OUTPUT_${infile}}
 			COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/zdoom.dir/${indir}
 			COMMAND ${ASSEMBLER} ${ASM_FLAGS} -o"${ASM_OUTPUT_${infile}}" "${CMAKE_CURRENT_SOURCE_DIR}/${indir}/${infile}${ASM_SOURCE_EXTENSION}"
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 08a1c4f4b..4f9e9ae22 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -2,9 +2,9 @@ cmake_minimum_required( VERSION 2.4 )
 
 add_subdirectory( lemon )
 add_subdirectory( re2c )
-if( WIN32 )
+if( WIN32 AND NOT CMAKE_SIZEOF_VOID_P MATCHES "8" )
 	add_subdirectory( fixrtext )
-endif( WIN32 )
+endif( WIN32 AND NOT CMAKE_SIZEOF_VOID_P MATCHES "8" )
 add_subdirectory( updaterevision )
 add_subdirectory( zipdir )