diff -r 5778c1daa9b1 -r 7f3080194808 src/arch/x86/isa/decoder/x87.isa
--- a/src/arch/x86/isa/decoder/x87.isa	Sat Jan 05 10:16:40 2013 -0600
+++ b/src/arch/x86/isa/decoder/x87.isa	Sat Jan 05 10:18:15 2013 -0600
@@ -109,8 +109,8 @@
                     0x3: Inst::FSINCOS();
                     0x4: frndint();
                     0x5: fscale();
-                    0x6: fsin();
-                    0x7: fcos();
+                    0x6: Inst::FSIN();
+                    0x7: Inst::FCOS();
                 }
                 default: Inst::FNSTCW(Mw);
             }
diff -r 5778c1daa9b1 -r 7f3080194808 src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py
--- a/src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py	Sat Jan 05 10:16:40 2013 -0600
+++ b/src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py	Sat Jan 05 10:18:15 2013 -0600
@@ -36,8 +36,13 @@
 # Authors: Gabe Black
 
 microcode = '''
-# FSIN
-# FCOS
+def macroop FSIN {
+    sinfp st(0), st(0)
+};
+
+def macroop FCOS {
+    cosfp st(0), st(0)
+};
 
 def macroop FSINCOS {
     sinfp ufp1, st(0)