diff --git a/spec/haskell/src/SEL4/Object/FPU/AARCH64.hs b/spec/haskell/src/SEL4/Object/FPU/AARCH64.hs
index ac4a4266f1..0165f78034 100644
--- a/spec/haskell/src/SEL4/Object/FPU/AARCH64.hs
+++ b/spec/haskell/src/SEL4/Object/FPU/AARCH64.hs
@@ -47,7 +47,7 @@ fpuRelease tcbPtr = do
 lazyFpuRestore :: PPtr TCB -> Kernel ()
 lazyFpuRestore tcbPtr = do
     flags <- threadGet tcbFlags tcbPtr
-    if (tcbFlagToWord (ArchFlag FpuDisabled) .&. flags /= 0)
+    if (isFlagSet (ArchFlag FpuDisabled) flags)
       then doMachineOp disableFpu
       else do
           doMachineOp enableFpu
diff --git a/spec/haskell/src/SEL4/Object/FPU/X64.hs b/spec/haskell/src/SEL4/Object/FPU/X64.hs
index 10368c1051..9a4aeed494 100644
--- a/spec/haskell/src/SEL4/Object/FPU/X64.hs
+++ b/spec/haskell/src/SEL4/Object/FPU/X64.hs
@@ -47,7 +47,7 @@ fpuRelease tcbPtr = do
 lazyFpuRestore :: PPtr TCB -> Kernel ()
 lazyFpuRestore tcbPtr = do
     flags <- threadGet tcbFlags tcbPtr
-    if (tcbFlagToWord (ArchFlag FpuDisabled) .&. flags /= 0)
+    if (isFlagSet (ArchFlag FpuDisabled) flags)
       then doMachineOp disableFpu
       else do
           doMachineOp enableFpu
diff --git a/spec/haskell/src/SEL4/Object/Structures.lhs b/spec/haskell/src/SEL4/Object/Structures.lhs
index 5cd0c0eefe..7fde732c62 100644
--- a/spec/haskell/src/SEL4/Object/Structures.lhs
+++ b/spec/haskell/src/SEL4/Object/Structures.lhs
@@ -508,3 +508,6 @@ Various operations on the free index of an Untyped cap.
 > tcbFlagToWord :: TcbFlag -> Word
 > tcbFlagToWord NoFlag = 0x0
 > tcbFlagToWord (ArchFlag archFlag) = archTcbFlagToWord archFlag
+
+> isFlagSet :: TcbFlag -> TcbFlags -> Bool
+> isFlagSet flag flags = tcbFlagToWord flag .&. flags /= 0
diff --git a/spec/haskell/src/SEL4/Object/TCB/AARCH64.hs b/spec/haskell/src/SEL4/Object/TCB/AARCH64.hs
index 805ab06d3d..f77eaba7e2 100644
--- a/spec/haskell/src/SEL4/Object/TCB/AARCH64.hs
+++ b/spec/haskell/src/SEL4/Object/TCB/AARCH64.hs
@@ -56,7 +56,7 @@ postModifyRegisters _ _ = return ()
 
 postSetFlags :: PPtr TCB -> TcbFlags -> Kernel ()
 postSetFlags t flags =
-    when (tcbFlagToWord (ArchFlag FpuDisabled) .&. flags /= 0) (fpuRelease t)
+    when (isFlagSet (ArchFlag FpuDisabled) flags) (fpuRelease t)
 
 -- Save and clear FPU state before setting the domain of a TCB, to ensure that
 -- we do not later write to cross-domain state.
diff --git a/spec/haskell/src/SEL4/Object/TCB/X64.lhs b/spec/haskell/src/SEL4/Object/TCB/X64.lhs
index 3528f9b810..b60fe3fa86 100644
--- a/spec/haskell/src/SEL4/Object/TCB/X64.lhs
+++ b/spec/haskell/src/SEL4/Object/TCB/X64.lhs
@@ -64,7 +64,7 @@ Here, cur = ksCurThread
 
 > postSetFlags :: PPtr TCB -> TcbFlags -> Kernel ()
 > postSetFlags t flags =
->     when (tcbFlagToWord (ArchFlag FpuDisabled) .&. flags /= 0) (fpuRelease t)
+>     when (isFlagSet (ArchFlag FpuDisabled) flags) (fpuRelease t)
 
 Save and clear FPU state before setting the domain of a TCB, to ensure that
 we do not later write to cross-domain state.