diff --git a/gnuradio-core/src/lib/filter/CMakeLists.txt b/gnuradio-core/src/lib/filter/CMakeLists.txt
index da16cd6..ce7e387 100644
--- a/gnuradio-core/src/lib/filter/CMakeLists.txt
+++ b/gnuradio-core/src/lib/filter/CMakeLists.txt
@@ -166,7 +166,7 @@ if(CMAKE_SYSTEM_PROCESSOR_x86)
     )
 endif()

-if(CMAKE_SYSTEM_PROCESSOR_x86 AND ${CMAKE_SYSTEM_PROCESSOR_x86} EQUAL 64)
+if(CMAKE_SYSTEM_PROCESSOR_x86 AND "${CMAKE_SYSTEM_PROCESSOR_x86}" STREQUAL "64")
     list(APPEND gnuradio_core_sources
         ${CMAKE_CURRENT_SOURCE_DIR}/float_dotprod_sse64.S
         ${CMAKE_CURRENT_SOURCE_DIR}/float_dotprod_3dnow64.S
@@ -180,7 +180,7 @@ if(CMAKE_SYSTEM_PROCESSOR_x86 AND ${CMAKE_SYSTEM_PROCESSOR_x86} EQUAL 64)
         ${CMAKE_CURRENT_SOURCE_DIR}/fcomplex_dotprod_sse64.S
         ${CMAKE_CURRENT_SOURCE_DIR}/short_dotprod_mmx64.S
     )
-elseif(CMAKE_SYSTEM_PROCESSOR_x86 AND ${CMAKE_SYSTEM_PROCESSOR_x86} EQUAL 32)
+elseif(CMAKE_SYSTEM_PROCESSOR_x86 AND "${CMAKE_SYSTEM_PROCESSOR_x86}" STREQUAL "32")
     list(APPEND gnuradio_core_sources
         ${CMAKE_CURRENT_SOURCE_DIR}/float_dotprod_sse.S
         ${CMAKE_CURRENT_SOURCE_DIR}/float_dotprod_3dnow.S