module CodeGen.Platform
       (callerSaves, activeStgRegs, haveRegBase, globalRegMaybe, freeReg)
       where

import CmmExpr
import FastBool
import Platform
import Reg

import qualified CodeGen.Platform.ARM        as ARM
import qualified CodeGen.Platform.ARM64      as ARM64
import qualified CodeGen.Platform.PPC        as PPC
import qualified CodeGen.Platform.PPC_Darwin as PPC_Darwin
import qualified CodeGen.Platform.SPARC      as SPARC
import qualified CodeGen.Platform.X86        as X86
import qualified CodeGen.Platform.X86_64     as X86_64
import qualified CodeGen.Platform.NoRegs     as NoRegs

-- | Returns 'True' if this global register is stored in a caller-saves
-- machine register.

callerSaves :: Platform -> GlobalReg -> Bool
callerSaves platform
 | platformUnregisterised platform = NoRegs.callerSaves
 | otherwise
 = case platformArch platform of
   ArchX86    -> X86.callerSaves
   ArchX86_64 -> X86_64.callerSaves
   ArchSPARC  -> SPARC.callerSaves
   ArchARM {} -> ARM.callerSaves
   ArchARM64  -> ARM64.callerSaves
   arch
    | arch `elem` [ArchPPC, ArchPPC_64] ->
       case platformOS platform of
       OSDarwin -> PPC_Darwin.callerSaves
       _        -> PPC.callerSaves

    | otherwise -> NoRegs.callerSaves

-- | Here is where the STG register map is defined for each target arch.
-- The order matters (for the llvm backend anyway)! We must make sure to
-- maintain the order here with the order used in the LLVM calling conventions.
-- Note that also, this isn't all registers, just the ones that are currently
-- possbily mapped to real registers.
activeStgRegs :: Platform -> [GlobalReg]
activeStgRegs platform
 | platformUnregisterised platform = NoRegs.activeStgRegs
 | otherwise
 = case platformArch platform of
   ArchX86    -> X86.activeStgRegs
   ArchX86_64 -> X86_64.activeStgRegs
   ArchSPARC  -> SPARC.activeStgRegs
   ArchARM {} -> ARM.activeStgRegs
   ArchARM64  -> ARM64.activeStgRegs
   arch
    | arch `elem` [ArchPPC, ArchPPC_64] ->
       case platformOS platform of
       OSDarwin -> PPC_Darwin.activeStgRegs
       _        -> PPC.activeStgRegs

    | otherwise -> NoRegs.activeStgRegs

haveRegBase :: Platform -> Bool
haveRegBase platform
 | platformUnregisterised platform = NoRegs.haveRegBase
 | otherwise
 = case platformArch platform of
   ArchX86    -> X86.haveRegBase
   ArchX86_64 -> X86_64.haveRegBase
   ArchSPARC  -> SPARC.haveRegBase
   ArchARM {} -> ARM.haveRegBase
   ArchARM64  -> ARM64.haveRegBase
   arch
    | arch `elem` [ArchPPC, ArchPPC_64] ->
       case platformOS platform of
       OSDarwin -> PPC_Darwin.haveRegBase
       _        -> PPC.haveRegBase

    | otherwise -> NoRegs.haveRegBase

globalRegMaybe :: Platform -> GlobalReg -> Maybe RealReg
globalRegMaybe platform
 | platformUnregisterised platform = NoRegs.globalRegMaybe
 | otherwise
 = case platformArch platform of
   ArchX86    -> X86.globalRegMaybe
   ArchX86_64 -> X86_64.globalRegMaybe
   ArchSPARC  -> SPARC.globalRegMaybe
   ArchARM {} -> ARM.globalRegMaybe
   ArchARM64  -> ARM64.globalRegMaybe
   arch
    | arch `elem` [ArchPPC, ArchPPC_64] ->
       case platformOS platform of
       OSDarwin -> PPC_Darwin.globalRegMaybe
       _        -> PPC.globalRegMaybe

    | otherwise -> NoRegs.globalRegMaybe

freeReg :: Platform -> RegNo -> FastBool
freeReg platform
 | platformUnregisterised platform = NoRegs.freeReg
 | otherwise
 = case platformArch platform of
   ArchX86    -> X86.freeReg
   ArchX86_64 -> X86_64.freeReg
   ArchSPARC  -> SPARC.freeReg
   ArchARM {} -> ARM.freeReg
   ArchARM64  -> ARM64.freeReg
   arch
    | arch `elem` [ArchPPC, ArchPPC_64] ->
       case platformOS platform of
       OSDarwin -> PPC_Darwin.freeReg
       _        -> PPC.freeReg

    | otherwise -> NoRegs.freeReg