
module SPARC.CodeGen.Amode (
	getAmode
)

where

import {-# SOURCE #-} SPARC.CodeGen.Gen32
import SPARC.CodeGen.Base
import SPARC.AddrMode
import SPARC.Imm
import SPARC.Instr
import SPARC.Regs
import SPARC.Base
import NCGMonad
import Size

import Cmm

import OrdList


-- | Generate code to reference a memory address.
getAmode 
	:: CmmExpr 	-- ^ expr producing an address
	-> NatM Amode

getAmode tree@(CmmRegOff _ _) 
	= getAmode (mangleIndexTree tree)

getAmode (CmmMachOp (MO_Sub _) [x, CmmLit (CmmInt i _)])
  | fits13Bits (-i)
  = do
       (reg, code) <- getSomeReg x
       let
         off  = ImmInt (-(fromInteger i))
       return (Amode (AddrRegImm reg off) code)


getAmode (CmmMachOp (MO_Add _) [x, CmmLit (CmmInt i _)])
  | fits13Bits i
  = do
       (reg, code) <- getSomeReg x
       let
     	 off  = ImmInt (fromInteger i)
       return (Amode (AddrRegImm reg off) code)

getAmode (CmmMachOp (MO_Add _) [x, y])
  = do
    (regX, codeX) <- getSomeReg x
    (regY, codeY) <- getSomeReg y
    let
    	code = codeX `appOL` codeY
    return (Amode (AddrRegReg regX regY) code)

getAmode (CmmLit lit)
  = do
	let imm__2	= litToImm lit
	tmp1 	<- getNewRegNat II32
	tmp2	<- getNewRegNat II32

	let code = toOL	[ SETHI (HI imm__2) tmp1
			, OR    False tmp1 (RIImm (LO imm__2)) tmp2]
		
	return (Amode (AddrRegReg tmp2 g0) code)

getAmode other
  = do
       (reg, code) <- getSomeReg other
       let
    	    off  = ImmInt 0
       return (Amode (AddrRegImm reg off) code)
