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|
Require Import Bedrock.Word.
(* Expression *)
(* THEORY: if we permit operations on joined types, we can represent
* vector operations without searching *)
Inductive CType: Set :=
| Words | list word
Definition cTypeToWord(type: CType): Type :=
match type with
| Int32 => word 32
| Int64 => word 64
| Join a b => (cTypeToWord a) * (cTypeToWord b)
end.
Definition bits(type: CType): nat :=
match type with
| Int32 => 32
| Int64 => 64
| Join a b => (bits a) + (bits b)
end.
Inductive UnaryOp :=
| CNot | COpp.
Inductive BinaryOp :=
| CPlus | CMinus | CMult
| CDiv | CAnd | COr
| CXor | CRShift | CLShift.
Inductive CTerm (type: CType) :=
| CConst : (word (bits type)) -> (CTerm type)
| CVar : Name -> CTerm type
| CJoin : forall t1 t2, CTerm t1 -> CTerm t2 -> CTerm (Join t1 t2)
| CLeft : CTerm (Join type _) -> CTerm type
| CRight : CTerm (Join _ type) -> CTerm type.
Inductive CExpr (type: CType) :=
| TermExpr : (CTerm type) -> (CExpr type)
| UnaryExpr : UnaryOp -> (CTerm type) -> (CExpr type)
| BinaryExpr : BinaryOp -> (CTerm type) -> (CTerm type) -> (CExpr type).
Inductive Sub (inType: CType) (outType: CType) :=
| CRet : Expr outType -> Sub inType outType
(* | Repeat *)
| CCompose : forall medType,
(Sub inType medType)
-> (Sub medType outType)
-> (Sub inType outType)
| CIte : (Sub inType Int32) (* condition *)
-> (Sub inType outType) (* then *)
-> (Sub inType outType) (* else *)
-> (Sub inType outType)
| CLet : Name -> CTerm ->
-> (Sub inType outType)
-> (Sub inType outType).
Definition bindTerm {valueType objectType} (var: Name) (value: CTerm valueType) (object: CTerm objectType): CTerm objectType :=
match valueType with
| objectType =>
match object with
| CConst _ => object
| CVar name => if (name = var) then value else object end
| CJoin left right =>
CJoin (bindTerm var value left) (bindTerm var value right)
| CLeft from => CLeft (bindTerm var value larger)
| CRight from => CRight (bindTerm var value larger)
end
| _ => object.
Definition bindExpr {valueType objectType} (var: Name) (value: CTerm valueType) (object: CExpr objectType): CExpr objectType :=
match object with
| TermExpr term => TermExpr (bindTerm var value term)
| UnaryExpr op term => UnaryExpr op (bindTerm var value term)
| BinaryExpr op term1 term2 =>
BinaryExpr op (bindTerm var value term1) (bindTerm var value term2)
end.
Definition bind {valueType fromType toType} (var: Name) (value: CTerm) (object: Sub fromType toType): Sub fromType toType :=
match object with
| CRet expr => CRet (bindExpr var value expr)
| CCompose left right =>
CCompose (bind var value left) (bind var value right)
| CIte cond thenSub elseSub =>
CIte (bind var value cond)
(bind var value thenSub)
(bind var value elseSub)
| CLet name bindTo sub =>
CLet name bindTo (bind var value sub)
end.
Inductive TermEquiv {t} (left: CTerm t) (right: (cTypeToWord t)) :=
| EquivInt32: forall (w: (word (bits Int32))), TermEquiv (CConst w) w
| EquivInt64: forall (w: (word (bits Int64))), TermEquiv (CConst w) w
| EquivJoin: forall aComp bComp aGallina bGallina,
TermEquiv aComp aGallina
-> TermEquiv bComp bGallina
-> TermEquiv (CJoin aComp bComp) (aGallina, bGallina)
| EquivLeft: forall aComp aGallina,
TermEquiv aComp aGallina
-> TermEquiv (CLeft aComp) (fst aGallina)
| EquivRight: forall aComp aGallina,
TermEquiv aComp aGallina
-> TermEquiv (CRight aComp) (snd aGallina).
Definition applyBinaryOp {n: nat} (op: UnaryOp) (a b: word n) :=
match op with
| CPlus => Word.plus a b
| CMinus => Word.minus a b
| CMult => Word.mult a b
| CDiv => Word.div a b
| CAnd => Word.and a b
| COr => Word.or a b
| CXor => Word.xor a b
| CRShift => Word.rshift a b
| CLShift => Word.lshift a b
end.
Definition applyUnaryOp {n: nat} (op: UnaryOp) (w: word n) :=
match op with
| CNot => Word.not w
| COpp => Word.opp w
end.
Inductive ExprEquiv {t} (left: CExpr t) (right: (cTypeToWord t)) :=
| EquivNop: forall aComp aGallina,
TermEquiv aComp aGallina
-> ExprEquiv (TermExpr aComp) aGallina
| EquivNot: forall aComp aGallina op,
TermEquiv aComp aGallina
-> ExprEquiv (UnaryExpr op aComp) (applyUnaryOp op aGallina)
| EquivPlus: forall aComp aGallina bComp bGallina op,
TermEquiv aComp aGallina
-> TermEquiv bComp bGallina
-> ExprEquiv (BinaryExpr op aComp bComp) (applyBinaryOp aGallina bGallina).
Inductive SubEquiv {fromType toType} (left: Sub fromType toType) (right: (cTypeToWord fromType) -> (cTypeToWord toType)) :=
| EquivRet: forall aComp aGallina,
ExprEquiv aComp aGallina
-> SubEquiv (CRet aComp) (fun x => aGallina)
| EquivComp: forall fComp fGallina gComp gGallina,
SubEquiv fComp fGallina
-> SubEquiv gComp gGallina
-> SubEquiv (CCompose fComp gComp) (fun x => gGallina (fGallina x))
| EquivIte: forall (fComp: Sub fromType Int32) fGallina gComp gGallina,
SubEquiv fComp fGallina
-> SubEquiv gComp gGallina
-> SubEquiv hComp hGallina
-> SubEquiv (CIte fComp gComp hComp)
(fun x => if (neq 0 (fGallina x)) then gGallina x else hGallina x)
| EquivLet: forall name bindTo sub fGallina,
SubEquiv (bind name bindTo sub) fGallina
-> SubEquiv (CLet name bindTo sub) fGallina.
|