diff --git a/lib/rscons.rb b/lib/rscons.rb
index e34fb97..411c642 100644
--- a/lib/rscons.rb
+++ b/lib/rscons.rb
@@ -8,12 +8,12 @@ require "rscons/monkey/module"
 require "rscons/monkey/string"
 
 # default builders
-require "rscons/builders/cc"
+require "rscons/builders/object"
 require "rscons/builders/program"
 
 module Rscons
   DEFAULT_BUILDERS = [
-    CC,
+    Object,
     Program,
   ]
 end
diff --git a/lib/rscons/builders/cc.rb b/lib/rscons/builders/cc.rb
deleted file mode 100644
index 87f746f..0000000
--- a/lib/rscons/builders/cc.rb
+++ /dev/null
@@ -1,39 +0,0 @@
-module Rscons
-  class CC < Builder
-    def default_variables(env)
-      {
-        'CC' => 'gcc',
-        'CFLAGS' => [],
-        'CPPFLAGS' => [],
-        'CPPPATH' => [],
-        'OBJSUFFIX' => '.o',
-        'CSUFFIX' => '.c',
-        'CCDEPGEN' => ['-MMD', '-MF', '$DEPFILE'],
-        'CCCOM' => ['$CC', '-c', '-o', '$TARGET', '$CCDEPGEN', '-I$[CPPPATH]', '$CPPFLAGS', '$CFLAGS', '$SOURCES']
-      }
-    end
-
-    def produces?(target, source, env)
-      target.has_suffix?(env['OBJSUFFIX']) and source.has_suffix?(env['CSUFFIX'])
-    end
-
-    def run(target, sources, cache, env)
-      vars = {
-        'TARGET' => target,
-        'SOURCES' => sources,
-        'DEPFILE' => target.set_suffix('.mf'),
-      }
-      command = env.build_command(env['CCCOM'], vars)
-      unless cache.up_to_date?(target, command, sources)
-        return false unless env.execute("CC #{target}", command)
-        deps = sources
-        if File.exists?(vars['DEPFILE'])
-          deps += env.parse_makefile_deps(vars['DEPFILE'], target)
-          FileUtils.rm_f(vars['DEPFILE'])
-        end
-        cache.register_build(target, command, deps.uniq)
-      end
-      target
-    end
-  end
-end
diff --git a/lib/rscons/builders/object.rb b/lib/rscons/builders/object.rb
new file mode 100644
index 0000000..c9a9cf9
--- /dev/null
+++ b/lib/rscons/builders/object.rb
@@ -0,0 +1,57 @@
+module Rscons
+  class Object < Builder
+    def default_variables(env)
+      {
+        'OBJSUFFIX' => '.o',
+
+        'AS' => 'gcc',
+        'ASFLAGS' => [],
+        'ASSUFFIX' => '.S',
+        'ASPPPATH' => '$CPPPATH',
+        'ASPPFLAGS' => '$CPPFLAGS',
+        'ASDEPGEN' => ['-MMD', '-MF', '$DEPFILE'],
+        'ASCOM' => ['$AS', '-c', '-o', '$TARGET', '$ASDEPGEN', '-I$[ASPPPATH]', '$ASPPFLAGS', '$ASFLAGS', '$SOURCES'],
+
+        'CC' => 'gcc',
+        'CFLAGS' => [],
+        'CPPFLAGS' => [],
+        'CPPPATH' => [],
+        'CSUFFIX' => '.c',
+        'CCDEPGEN' => ['-MMD', '-MF', '$DEPFILE'],
+        'CCCOM' => ['$CC', '-c', '-o', '$TARGET', '$CCDEPGEN', '-I$[CPPPATH]', '$CPPFLAGS', '$CFLAGS', '$SOURCES'],
+      }
+    end
+
+    def produces?(target, source, env)
+      target.has_suffix?(env['OBJSUFFIX']) and (
+        source.has_suffix?(env['ASSUFFIX']) or
+        source.has_suffix?(env['CSUFFIX']))
+    end
+
+    def run(target, sources, cache, env)
+      vars = {
+        'TARGET' => target,
+        'SOURCES' => sources,
+        'DEPFILE' => target.set_suffix('.mf'),
+      }
+      com_prefix = if sources.first.has_suffix?(env['ASSUFFIX'])
+                     'AS'
+                   elsif sources.first.has_suffix?(env['CSUFFIX'])
+                     'CC'
+                   else
+                     raise "Error: unknown input file type: #{sources.first.inspect}"
+                   end
+      command = env.build_command(env["#{com_prefix}COM"], vars)
+      unless cache.up_to_date?(target, command, sources)
+        return false unless env.execute("#{com_prefix} #{target}", command)
+        deps = sources
+        if File.exists?(vars['DEPFILE'])
+          deps += env.parse_makefile_deps(vars['DEPFILE'], target)
+          FileUtils.rm_f(vars['DEPFILE'])
+        end
+        cache.register_build(target, command, deps.uniq)
+      end
+      target
+    end
+  end
+end