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(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the GNU Library General Public License, with    *)
(*  the special exception on linking described in file ../LICENSE.     *)
(*                                                                     *)
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(* $Id$ *)

(** 32-bit integers.

   This module provides operations on the type [int32]
   of signed 32-bit integers.  Unlike the built-in [int] type,
   the type [int32] is guaranteed to be exactly 32-bit wide on all
   platforms.  All arithmetic operations over [int32] are taken
   modulo 2{^32}.

   Performance notice: values of type [int32] occupy more memory
   space than values of type [int], and arithmetic operations on
   [int32] are generally slower than those on [int].  Use [int32]
   only when the application requires exact 32-bit arithmetic. *)

val zero : int32
(** The 32-bit integer 0. *)

val one : int32
(** The 32-bit integer 1. *)

val minus_one : int32
(** The 32-bit integer -1. *)

external neg : int32 -> int32 = "%int32_neg"
(** Unary negation. *)

external add : int32 -> int32 -> int32 = "%int32_add"
(** Addition. *)

external sub : int32 -> int32 -> int32 = "%int32_sub"
(** Subtraction. *)

external mul : int32 -> int32 -> int32 = "%int32_mul"
(** Multiplication. *)

external div : int32 -> int32 -> int32 = "%int32_div"
(** Integer division.  Raise [Division_by_zero] if the second 
   argument is zero.  This division rounds the real quotient of
   its arguments towards zero, as specified for {!Pervasives.(/)}. *)

external rem : int32 -> int32 -> int32 = "%int32_mod"
(** Integer remainder.  If [y] is not zero, the result
   of [Int32.rem x y] satisfies the following properties:
   [Int32.zero <= Int32.rem x y < Int32.abs y] and
   [x = Int32.add (Int32.mul (Int32.div x y) y) (Int32.rem x y)].
   If [y = 0], [Int32.rem x y] raises [Division_by_zero]. *)

val succ : int32 -> int32
(** Successor.  [Int32.succ x] is [Int32.add x Int32.one]. *)

val pred : int32 -> int32
(** Predecessor.  [Int32.pred x] is [Int32.sub x Int32.one]. *)

val abs : int32 -> int32
(** Return the absolute value of its argument. *)

val max_int : int32
(** The greatest representable 32-bit integer, 2{^31} - 1. *)

val min_int : int32
(** The smallest representable 32-bit integer, -2{^31}. *)


external logand : int32 -> int32 -> int32 = "%int32_and"
(** Bitwise logical and. *)

external logor : int32 -> int32 -> int32 = "%int32_or"
(** Bitwise logical or. *)

external logxor : int32 -> int32 -> int32 = "%int32_xor"
(** Bitwise logical exclusive or. *)

val lognot : int32 -> int32
(** Bitwise logical negation *)

external shift_left : int32 -> int -> int32 = "%int32_lsl"
(** [Int32.shift_left x y] shifts [x] to the left by [y] bits.
   The result is unspecified if [y < 0] or [y >= 32]. *)

external shift_right : int32 -> int -> int32 = "%int32_asr"
(** [Int32.shift_right x y] shifts [x] to the right by [y] bits.
   This is an arithmetic shift: the sign bit of [x] is replicated
   and inserted in the vacated bits.
   The result is unspecified if [y < 0] or [y >= 32]. *)

external shift_right_logical : int32 -> int -> int32 = "%int32_lsr"
(** [Int32.shift_right_logical x y] shifts [x] to the right by [y] bits.
   This is a logical shift: zeroes are inserted in the vacated bits
   regardless of the sign of [x].
   The result is unspecified if [y < 0] or [y >= 32]. *)

external of_int : int -> int32 = "%int32_of_int"
(** Convert the given integer (type [int]) to a 32-bit integer (type [int32]). *)

external to_int : int32 -> int = "%int32_to_int"
(** Convert the given 32-bit integer (type [int32]) to an
   integer (type [int]).  On 32-bit platforms, the 32-bit integer
   is taken modulo 2{^31}, i.e. the high-order bit is lost
   during the conversion.  On 64-bit platforms, the conversion
   is exact. *)

external of_float : float -> int32 = "int32_of_float"
(** Convert the given floating-point number to a 32-bit integer,
   discarding the fractional part (truncate towards 0).
   The result of the conversion is undefined if, after truncation,
   the number is outside the range \[{!Int32.min_int}, {!Int32.max_int}\]. *)

external to_float : int32 -> float = "int32_to_float"
(** Convert the given 32-bit integer to a floating-point number. *)

external of_string : string -> int32 = "int32_of_string"
(** Convert the given string to a 32-bit integer.
   The string is read in decimal (by default) or in hexadecimal,
   octal or binary if the string begins with [0x], [0o] or [0b]
   respectively.
   Raise [Failure "int_of_string"] if the given string is not
   a valid representation of an integer. *)

val to_string : int32 -> string
(** Return the string representation of its argument, in signed decimal. *)

external format : string -> int32 -> string = "int32_format"
(** [Int32.format fmt n] return the string representation of the
   32-bit integer [n] in the format specified by [fmt].
   [fmt] is a [Printf]-style format containing exactly
   one [%d], [%i], [%u], [%x], [%X] or [%o] conversion specification.
   This function is deprecated; use {!Printf.sprintf} with a [%lx] format
   instead. *)

type t = int32
(** An alias for the type of 32-bit integers. *)

val compare: t -> t -> int
(** The comparison function for 32-bit integers, with the same specification as
    {!Pervasives.compare}.  Along with the type [t], this function [compare]
    allows the module [Int32] to be passed as argument to the functors
    {!Set.Make} and {!Map.Make}. *)