Hi, I'd like to know if this should work: -- GHC coercion getFloat :: BHeader -> Get Float getFloat h = case endianness h of LittleEndian -> fmap (coerce . fromIntegral) getWord32le BigEndian -> fmap (coerce . fromIntegral) getWord32be where coerce (I32# x) = F# (unsafeCoerce# x) -- GHC coercion getDouble :: BHeader -> Get Double getDouble h = case endianness h of LittleEndian -> fmap (coerce . fromIntegral) getWord64le BigEndian -> fmap (coerce . fromIntegral) getWord64be where coerce (I64# x) = D# (unsafeCoerce# x) Loading this into ghci compiles fine (but I haven't try to parse data), but compiling with ghc (6.10.1 or 6.10.4) reports: /tmp/ghc1967_0/ghc1967_0.s: Assembler messages: /tmp/ghc1967_0/ghc1967_0.s:287:0: Error: bad register name `%fake0' /tmp/ghc1967_0/ghc1967_0.s:349:0: Error: bad register name `%fake0' Thanks for any help, Thu