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|
Require Import Coqlib.
Require Import Integers.
Require Import Values.
Definition is_bitfield stop start :=
(Z.leb start stop)
&& (Z.geb start Z.zero)
&& (Z.ltb stop Int.zwordsize).
Definition extfz stop start v :=
if is_bitfield stop start
then
let stop' := Z.add stop Z.one in
match v with
| Vint w =>
Vint (Int.shru (Int.shl w (Int.repr (Z.sub Int.zwordsize stop'))) (Int.repr (Z.sub Int.zwordsize (Z.sub stop' start))))
| _ => Vundef
end
else Vundef.
Definition extfs stop start v :=
if is_bitfield stop start
then
let stop' := Z.add stop Z.one in
match v with
| Vint w =>
Vint (Int.shr (Int.shl w (Int.repr (Z.sub Int.zwordsize stop'))) (Int.repr (Z.sub Int.zwordsize (Z.sub stop' start))))
| _ => Vundef
end
else Vundef.
Definition zbitfield_mask stop start :=
(Z.shiftl 1 (Z.succ stop)) - (Z.shiftl 1 start).
Definition bitfield_mask stop start :=
Vint(Int.repr (zbitfield_mask stop start)).
Definition bitfield_maskl stop start :=
Vlong(Int64.repr (zbitfield_mask stop start)).
Definition insf stop start prev fld :=
let mask := bitfield_mask stop start in
if is_bitfield stop start
then
Val.or (Val.and prev (Val.notint mask))
(Val.and (Val.shl fld (Vint (Int.repr start))) mask)
else Vundef.
Definition is_bitfieldl stop start :=
(Z.leb start stop)
&& (Z.geb start Z.zero)
&& (Z.ltb stop Int64.zwordsize).
Definition extfzl stop start v :=
if is_bitfieldl stop start
then
let stop' := Z.add stop Z.one in
match v with
| Vlong w =>
Vlong (Int64.shru' (Int64.shl' w (Int.repr (Z.sub Int64.zwordsize stop'))) (Int.repr (Z.sub Int64.zwordsize (Z.sub stop' start))))
| _ => Vundef
end
else Vundef.
Definition extfsl stop start v :=
if is_bitfieldl stop start
then
let stop' := Z.add stop Z.one in
match v with
| Vlong w =>
Vlong (Int64.shr' (Int64.shl' w (Int.repr (Z.sub Int64.zwordsize stop'))) (Int.repr (Z.sub Int64.zwordsize (Z.sub stop' start))))
| _ => Vundef
end
else Vundef.
Definition insfl stop start prev fld :=
let mask := bitfield_maskl stop start in
if is_bitfieldl stop start
then
Val.orl (Val.andl prev (Val.notl mask))
(Val.andl (Val.shll fld (Vint (Int.repr start))) mask)
else Vundef.
Fixpoint highest_bit (x : Z) (n : nat) : Z :=
match n with
| O => 0
| S n1 =>
let n' := Z.of_N (N_of_nat n) in
if Z.testbit x n'
then n'
else highest_bit x n1
end.
Definition int_highest_bit (x : int) : Z :=
highest_bit (Int.unsigned x) (31%nat).
Definition int64_highest_bit (x : int64) : Z :=
highest_bit (Int64.unsigned x) (63%nat).
Definition val_shrx (v1 v2: val): val :=
match v1, v2 with
| Vint n1, Vint n2 =>
if Int.ltu n2 (Int.repr 31)
then Vint(Int.shrx n1 n2)
else Vundef
| _, _ => Vundef
end.
Definition val_shrxl (v1 v2: val): val :=
match v1, v2 with
| Vlong n1, Vint n2 =>
if Int.ltu n2 (Int.repr 63)
then Vlong(Int64.shrx' n1 n2)
else Vundef
| _, _ => Vundef
end.
|
