2 -- | Free regs map for PowerPC
3 module RegAlloc.Linear.PPC.FreeRegs
16 -- The PowerPC has 32 integer and 32 floating point registers.
17 -- This is 32bit PowerPC, so Word64 is inefficient - two Word32s are much
19 -- Note that when getFreeRegs scans for free registers, it starts at register
20 -- 31 and counts down. This is a hack for the PowerPC - the higher-numbered
21 -- registers are callee-saves, while the lower regs are caller-saves, so it
22 -- makes sense to start at the high end.
23 -- Apart from that, the code does nothing PowerPC-specific, so feel free to
24 -- add your favourite platform to the #if (if you have 64 registers but only
27 data FreeRegs = FreeRegs !Word32 !Word32
28 deriving( Show ) -- The Show is used in an ASSERT
30 noFreeRegs :: FreeRegs
31 noFreeRegs = FreeRegs 0 0
33 releaseReg :: RealReg -> FreeRegs -> FreeRegs
34 releaseReg (RealRegSingle r) (FreeRegs g f)
35 | r > 31 = FreeRegs g (f .|. (1 `shiftL` (r - 32)))
36 | otherwise = FreeRegs (g .|. (1 `shiftL` r)) f
39 = panic "RegAlloc.Linear.PPC.releaseReg: bad reg"
41 initFreeRegs :: FreeRegs
42 initFreeRegs = foldr releaseReg noFreeRegs allocatableRegs
44 getFreeRegs :: RegClass -> FreeRegs -> [RealReg] -- lazilly
45 getFreeRegs cls (FreeRegs g f)
46 | RcDouble <- cls = go f (0x80000000) 63
47 | RcInteger <- cls = go g (0x80000000) 31
48 | otherwise = pprPanic "RegAllocLinear.getFreeRegs: Bad register class" (ppr cls)
51 go x m i | x .&. m /= 0 = RealRegSingle i : (go x (m `shiftR` 1) $! i-1)
52 | otherwise = go x (m `shiftR` 1) $! i-1
54 allocateReg :: RealReg -> FreeRegs -> FreeRegs
55 allocateReg (RealRegSingle r) (FreeRegs g f)
56 | r > 31 = FreeRegs g (f .&. complement (1 `shiftL` (r - 32)))
57 | otherwise = FreeRegs (g .&. complement (1 `shiftL` r)) f
60 = panic "RegAlloc.Linear.PPC.allocateReg: bad reg"