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|
(*
* This module generates the machine code emitter of an architecture
* given a machine description.
*
*)
functor MDLGenMC(Comp : MDL_COMPILE) : MDL_GEN_MODULE =
struct
structure Comp = Comp
structure Ast = Comp.Ast
structure Env = Comp.Env
structure T = Comp.Trans
structure W = Word32
open Ast Comp.Util Comp.Error
infix << || &&
val op << = W.<<
val op || = W.orb
val op && = W.andb
val notb = W.notb
val itow = W.fromInt
val itos = Int.toString
fun gen md =
let (* name of the functor and signature *)
val strName = Comp.strname md "MCEmitter"
val sigName = "INSTRUCTION_EMITTER"
(* Is debugging turned on? *)
val debugOn = Comp.debugging md "MC"
(* Arguments for the functor *)
val args = ["structure Instr : "^Comp.signame md "INSTR",
"structure MLTreeEval : MLTREE_EVAL where T = Instr.T",
"structure Stream : INSTRUCTION_STREAM ",
"structure CodeString : CODE_STRING"
] @
(if debugOn then
["structure Assembler : INSTRUCTION_EMITTER",
" where I = Instr and S = MLTreeStream.S.Stream"
]
else [])
(* Instruction formats that are declared in the description *)
val formats = Comp.formats md
(* Instruction widths that are defined in this architecture *)
val widths = ListMergeSort.uniqueSort Int.compare
(foldr (fn ((SOME w,_),l) => w::l | (_,l) => l) []
formats)
(* The Instruction structure *)
val env = Env.lookupStr (Comp.env md) (IDENT([],"Instruction"))
(* Make sure that all widths are either 8, 16, 24, or 32 bits *)
val _ = app
(fn w =>
if w < 8 orelse w > 32 orelse w mod 8 <> 0 then
error("instruction format must be 8, 16, 24, or 32 bits; found"^itos w)
else ()) widths
(* Endianess *)
val endianess = Comp.endianess md
(* Name of an emit function *)
fun emit id = "emit_"^id
(*
* For each width N, generate a function eWordN for emitting a word
* of that width.
*)
val emitFuns =
let val DUMMYbind = FUNbind("dummy",[])
fun mkEmitWord width =
let fun f 0 = []
| f 8 = [VAL("b8",ID "w")]
| f b = VAL("b"^itos b,ID "w")::
VAL("w",SLR(ID "w",WORD32exp 0w8))::f(b - 8)
fun g 0 = []
| g b = APP("eByteW",ID("b"^itos b))::g(b - 8)
val debug =
if debugOn then
[VAL("_", ID "print(\"0x\"^Word32.toString w^\"\\t\")")]
else []
val body = case endianess of
BIG => g width
| LITTLE => rev(g width)
in FUNbind("eWord"^itos width,
[CLAUSE([IDpat "w"],
NONE,
LET(debug@rev(f width),SEQexp body))])
end
in FUNdecl(map mkEmitWord widths) end
(* Functions for emitting the encoding for a cell *)
val cellFuns =
let fun mkEmitCell(CELLdecl{id, from, ...}) =
FUN'(emit id, IDpat "r",
APP("itow", APP("CellsBasis.physicalRegisterNum", ID "r")))
in FUNdecl(map mkEmitCell (Comp.cells md)) end
(*
* For each datatype T defined in the structure Instruction that
* has code generation annotations defined, generate a function emit_T.
*)
val datatypeFuns =
let fun WORD w = TYPEDexp(WORD32exp w,WORD32ty)
fun mkEmitDatatypes([], fbs) = rev fbs
| mkEmitDatatypes(DATATYPEbind{id,mc,cbs,...}::dbs, fbs) =
let fun missing() =
error("machine encoding is missing for constructor "^id)
fun loop(w, [], cs, found) = (w, rev cs, found)
| loop(w, (cb as CONSbind{id, ty, mc, ...})::cbs,
cs, found) =
let val (e, found) =
case (mc, w) of
(NONE, SOME(x::_)) => (WORD(itow x), true)
| (NONE, SOME []) => (missing(); (WORD 0w0, true))
| (NONE, NONE) => (APP("error",STRINGexp id), found)
| (SOME(WORDmc w'), SOME(w::l')) =>
(if itow w <> w' then
error ("constructor "^id^" encoding is 0x"^
W.toString w'^" but is expecting 0x"^
W.toString(itow w)) else ();
(WORD w', true))
| (SOME(WORDmc w'), SOME []) => (WORD w', true)
| (SOME(WORDmc w'), NONE) => (WORD w', true)
| (SOME(EXPmc e), _) => (e, true)
val w = case w of NONE => NONE
| SOME(_::w) => SOME w
| SOME [] => (missing(); NONE)
in loop(w, cbs,
T.mapConsToClause
{prefix=["I"], pat=fn p=>p, exp=e} cb::cs,
found)
end
val (w, cs, found) = loop(mc, cbs, [], false)
val _ = case w of
SOME(_::_) =>
error("Extra machine encodings in datatype "^id)
| _ => ()
in mkEmitDatatypes(dbs,
if found then FUNbind(emit id, cs)::fbs else fbs)
end
val dbs = Env.datatypeDefinitions env
in FUNdecl(mkEmitDatatypes(dbs,[]))
end
(*
* Generate a formatting function for each machine instruction format
* defined in the machine description.
*)
val formatFuns =
let fun mkFormat(SOME width, FORMATbind(formatName, fields, NONE)) =
mkDefinedFormat(width, formatName, fields)
| mkFormat(NONE, FORMATbind(formatName, fields, NONE)) =
(error("missing width in format "^formatName);
FUNbind(formatName, []))
| mkFormat(_, FORMATbind(formatName, fields, SOME e)) =
mkFormatFun(formatName, fields, e)
(*
* Generate an expression that builds up the format
*)
and mkDefinedFormat(totalWidth, formatName, fields) =
let (* factor out the constant and the variable part *)
fun loop([], bit, constant, exps) = (bit, constant, exps)
| loop(FIELD{id, width, value, sign, ...}::fs,
bit, constant, exps) =
let val width =
case width of
WIDTH w => w
| RANGE(from, to) =>
(if bit <> from then
error("field "^id^
" in format "^formatName^
" starts from bit "^itos from^
" (bit "^itos bit^" expected")
else ();
to - from + 1)
val mask = (0w1 << Word.fromInt width) - 0w1
val (constant, exps) =
case value of
SOME v =>
(if (v && (notb mask)) <> 0w0 then
error("value 0x"^W.toString v^
"in field "^id^
" is out of range")
else ();
(constant || (v << Word.fromInt bit),
exps))
| NONE =>
let val e = ID id
val e = if sign = UNSIGNED then e else
ANDB(e,WORD32exp mask)
val e = SLL(e,WORD32exp(itow bit))
in (constant, e::exps) end
in loop(fs, bit+width, constant, exps) end
val (realWidth, constant, exps) =
loop(rev fields, 0, 0w0, [])
in if realWidth <> totalWidth then
error("format "^formatName^" is declared to have "^
itos totalWidth^" bits but I counted "^
itos realWidth)
else ();
mkFormatFun(formatName, fields,
APP("eWord"^itos totalWidth,
foldr PLUS (WORD32exp constant) exps))
end
(* Generate a format function that includes implicit
* argument conversions.
*)
and mkFormatFun(id, fields, exp) =
FUNbind(id, [CLAUSE(
[RECORDpat(foldr (fn (FIELD{id="",...}, fs) => fs
| (FIELD{value=SOME _,...}, fs) => fs
| (FIELD{id,...},fs) => (id,IDpat id)::fs ) [] fields, false)],
NONE,
LET(foldr (fn (FIELD{id,cnv=NOcnv, ...},ds) => ds
| (FIELD{id,cnv=CELLcnv k, ...},ds) =>
VAL(id, APP(emit k,ID id))::ds
| (FIELD{id,cnv=FUNcnv f, ...},ds) =>
VAL(id, APP(emit f,ID id))::ds
) [] fields, exp))])
in FUNdecl(map mkFormat (Comp.formats md)) end
(* The main emitter function *)
val emitInstrFun =
let fun mkEmitInstr(cb as CONSbind{id, mc, ...}) =
T.mapConsToClause
{prefix=["I"],pat=fn p=>p,
exp=case mc of
SOME(EXPmc e) => e
| _ => APP("error", STRINGexp id)
} cb
val instructions = Comp.instructions md
in FUNdecl[FUNbind("emitInstr", map mkEmitInstr instructions)]
end
(* Body of the module *)
val strBody =
[$["structure I = Instr",
"structure C = I.C",
"structure Constant = I.Constant",
"structure T = I.T",
"structure S = Stream",
"structure P = S.P",
"structure W = Word32",
"",
"(* "^Comp.name md^" is "^
(case endianess of BIG => "big" | LITTLE => "little")^
" endian *)",
""
],
Comp.errorHandler md "MC",
$["fun makeStream _ =",
"let infix && || << >> ~>>",
" val op << = W.<<",
" val op >> = W.>>",
" val op ~>> = W.~>>",
" val op || = W.orb",
" val op && = W.andb",
" val itow = W.fromInt",
" fun emit_bool false = 0w0 : W.word",
" | emit_bool true = 0w1 : W.word",
" val emit_int = itow",
" fun emit_word w = w",
" fun emit_label l = itow(Label.addrOf l)",
" fun emit_labexp le = itow(MLTreeEval.valueOf le)",
" fun emit_const c = itow(Constant.valueOf c)",
" val w32ToByte = Word8.fromLarge o Word32.toLarge",
" val loc = ref 0",
"",
" (* emit a byte *)",
" fun eByte b =",
" let val i = !loc in loc := i + 1; CodeString.update(i,b) end",
"",
" (* emit the low order byte of a word *)",
" (* note: fromLargeWord strips the high order bits! *)",
" fun eByteW w =",
" let val i = !loc",
" in loc := i + 1; CodeString.update(i, w32ToByte w) end",
"",
" fun doNothing _ = ()",
" fun fail _ = raise Fail \"MCEmitter\"",
" fun getAnnotations () = error \"getAnnotations\"",
"",
" fun pseudoOp pOp = P.emitValue{pOp=pOp, loc= !loc,emit=eByte}",
"",
" fun init n = (CodeString.init n; loc := 0)",
"",
(if debugOn then
"val S.STREAM{emit=asm,...} = Assembler.makeStream()"
else ""
)
],
emitFuns,
cellFuns,
datatypeFuns,
formatFuns,
Comp.declOf md "MC",
$[" fun emitter instr =",
" let"
],
emitInstrFun,
$[" in",
(if debugOn then
" emitInstr instr; asm instr"
else
" emitInstr instr"
),
" end",
"",
"fun emitInstruction(I.ANNOTATION{i, ...}) = emitInstruction(i)",
" | emitInstruction(I.INSTR(i)) = emitter(i)",
" | emitInstruction(I.LIVE _) = ()",
" | emitInstruction(I.KILL _) = ()",
"| emitInstruction _ = error \"emitInstruction\"",
"",
"in S.STREAM{beginCluster=init,",
" pseudoOp=pseudoOp,",
" emit=emitInstruction,",
" endCluster=fail,",
" defineLabel=doNothing,",
" entryLabel=doNothing,",
" comment=doNothing,",
" exitBlock=doNothing,",
" annotation=doNothing,",
" getAnnotations=getAnnotations",
" }",
"end"
]
]
in Comp.codegen md "emit/MC"
[Comp.mkFct md "MCEmitter" args sigName strBody]
end
end
|
