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|
module X86.Cond (
Cond(..),
condUnsigned,
condToSigned,
condToUnsigned,
maybeFlipCond
)
where
data Cond
= ALWAYS -- What's really used? ToDo
| EQQ
| GE
| GEU
| GTT
| GU
| LE
| LEU
| LTT
| LU
| NE
| NEG
| POS
| CARRY
| OFLO
| PARITY
| NOTPARITY
deriving Eq
condUnsigned :: Cond -> Bool
condUnsigned GU = True
condUnsigned LU = True
condUnsigned GEU = True
condUnsigned LEU = True
condUnsigned _ = False
condToSigned :: Cond -> Cond
condToSigned GU = GTT
condToSigned LU = LTT
condToSigned GEU = GE
condToSigned LEU = LE
condToSigned x = x
condToUnsigned :: Cond -> Cond
condToUnsigned GTT = GU
condToUnsigned LTT = LU
condToUnsigned GE = GEU
condToUnsigned LE = LEU
condToUnsigned x = x
-- | @maybeFlipCond c@ returns @Just c'@ if it is possible to flip the
-- arguments to the conditional @c@, and the new condition should be @c'@.
maybeFlipCond :: Cond -> Maybe Cond
maybeFlipCond cond = case cond of
EQQ -> Just EQQ
NE -> Just NE
LU -> Just GU
GU -> Just LU
LEU -> Just GEU
GEU -> Just LEU
LTT -> Just GTT
GTT -> Just LTT
LE -> Just GE
GE -> Just LE
_other -> Nothing
|
