(* *********************************************************************)
(*                                                                     *)
(*              The Compcert verified compiler                         *)
(*                                                                     *)
(*          Xavier Leroy, INRIA Paris-Rocquencourt                     *)
(*          Jacques-Henri Jourdan, INRIA Paris-Rocquencourt            *)
(*                                                                     *)
(*  Copyright Institut National de Recherche en Informatique et en     *)
(*  Automatique.  All rights reserved.  This file is distributed       *)
(*  under the terms of the GNU General Public License as published by  *)
(*  the Free Software Foundation, either version 2 of the License, or  *)
(*  (at your option) any later version.  This file is also distributed *)
(*  under the terms of the INRIA Non-Commercial License Agreement.     *)
(*                                                                     *)
(* *********************************************************************)
(** Architecture-dependent parameters for ARM *)
(*From Flocq*)
Definition ptr64 := false.
Parameter big_endian: bool.
Definition align_int64 := 8%Z.
Definition align_float64 := 8%Z.
Definition splitlong := true.
Definition default_nan_64 := (false, iter_nat 51 _ xO xH).
Definition default_nan_32 := (false, iter_nat 22 _ xO xH).
(** Choose the first signaling NaN, if any; otherwise choose the first NaN; otherwise use default. *)
Definition choose_nan (is_signaling: positive -> bool)
(default: bool * positive)
(l0: list (bool * positive)) : bool * positive :=
let fix choose_snan (l1: list (bool * positive)) :=
match l1 with
| nil =>
match l0 with nil => default | n :: _ => n end
| ((s, p) as n) :: l1 =>
if is_signaling p then n else choose_snan l1
end
in choose_snan l0.
Definition choose_nan_64 :=
choose_nan (fun p => negb (Pos.testbit p 51)) default_nan_64.
Definition choose_nan_32 :=
choose_nan (fun p => negb (Pos.testbit p 22)) default_nan_32.

Lemma choose_nan_64_idem: forall n,
choose_nan_64 (n :: n :: nil) = choose_nan_64 (n :: nil).