diff -r fb4a3a61bc74 src/arch/x86/isa/decoder/x87.isa
--- a/src/arch/x86/isa/decoder/x87.isa	Wed Nov 04 13:22:15 2009 -0500
+++ b/src/arch/x86/isa/decoder/x87.isa	Fri Nov 06 16:24:44 2009 -0500
@@ -124,7 +124,7 @@
                     0x0: fprem();
                     0x1: fyl2xp1();
                     0x2: fsqrt();
-                    0x3: fsincos();
+                    0x3: Inst::FSINCOS();
                     0x4: frndint();
                     0x5: fscale();
                     0x6: fsin();
diff -r fb4a3a61bc74 src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py
--- a/src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py	Wed Nov 04 13:22:15 2009 -0500
+++ b/src/arch/x86/isa/insts/x87/transcendental_functions/trigonometric_functions.py	Fri Nov 06 16:24:44 2009 -0500
@@ -56,7 +56,14 @@
 microcode = '''
 # FSIN
 # FCOS
-# FSINCOS
+
+def macroop FSINCOS {
+    sinfp ufp1, st(0)
+    cosfp ufp2, st(0)
+    movfp st(0), ufp1
+    movfp st(-1), ufp2, spm=-1
+};
+
 # FPTAN
 # FPATAN
 '''
diff -r fb4a3a61bc74 src/arch/x86/isa/microops/fpop.isa
--- a/src/arch/x86/isa/microops/fpop.isa	Wed Nov 04 13:22:15 2009 -0500
+++ b/src/arch/x86/isa/microops/fpop.isa	Fri Nov 06 16:24:44 2009 -0500
@@ -270,6 +270,21 @@
     class Sqrtfp(FpOp):
         code = 'FpDestReg = sqrt(FpSrcReg2);'
 
+    class Cosfp(FpOp):
+        def __init__(self, dest, src1, spm=0, \
+                SetStatus=False, dataSize="env.dataSize"):
+            super(Cosfp, self).__init__(dest, src1, "InstRegIndex(0)", \
+                    spm, SetStatus, dataSize)
+        code = 'FpDestReg = cos(FpSrcReg1);'
+
+    class Sinfp(FpOp):
+        def __init__(self, dest, src1, spm=0, \
+                SetStatus=False, dataSize="env.dataSize"):
+            super(Sinfp, self).__init__(dest, src1, "InstRegIndex(0)", \
+                    spm, SetStatus, dataSize)
+        code = 'FpDestReg = sin(FpSrcReg1);'
+
+
     # Conversion microops
     class ConvOp(FpOp):
         abstract = True