-- | Free regs map for i386 and x86_64 module RegAlloc.Linear.X86.FreeRegs where import Regs import Data.Word import Data.Bits import Data.List type FreeRegs = Word32 noFreeRegs :: FreeRegs noFreeRegs = 0 releaseReg :: RegNo -> FreeRegs -> FreeRegs releaseReg n f = f .|. (1 `shiftL` n) initFreeRegs :: FreeRegs initFreeRegs = foldr releaseReg noFreeRegs allocatableRegs getFreeRegs :: RegClass -> FreeRegs -> [RegNo] -- lazilly getFreeRegs cls f = go f 0 where go 0 _ = [] go n m | n .&. 1 /= 0 && regClass (RealReg m) == cls = m : (go (n `shiftR` 1) $! (m+1)) | otherwise = go (n `shiftR` 1) $! (m+1) -- ToDo: there's no point looking through all the integer registers -- in order to find a floating-point one. allocateReg :: RegNo -> FreeRegs -> FreeRegs allocateReg r f = f .&. complement (1 `shiftL` fromIntegral r)