diff --git a/src/arch/x86/isa/microops/fpop.isa b/src/arch/x86/isa/microops/fpop.isa
index 4d85cf3e18..aa89ca9347 100644
--- a/src/arch/x86/isa/microops/fpop.isa
+++ b/src/arch/x86/isa/microops/fpop.isa
@@ -258,9 +258,9 @@ let {{
 
     class Movfp(Fp2Op):
         code = '''
-        if(dataSize == 4) {
-            FpDestReg_uqw = (0xFFFFFFFF00000000 & FpDestReg_uqw) |
-            (0x00000000FFFFFFFF & FpSrcReg1_uqw);
+        if (dataSize == 4) {
+            FpDestReg_uqw = mbits(FpDestReg_uqw, 63, 32) |
+                            mbits(FpSrcReg1_uqw, 31, 0);
         } else {
             FpDestReg_uqw = FpSrcReg1_uqw;
         }