(***********************************************************************)
(*                                                                     *)
(*                           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.         *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(* Module [Int32]: 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
val one : int32
val minus_one : int32
      (* The 32-bit integers 0, 1, -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. *)
external rem : int32 -> int32 -> int32 = "%int32_mod"
      (* Integer remainder.  If [x >= 0] and [y > 0], the result
           of [Int32.rem x y] satisfies the following properties:
           [0 <= Int32.rem x y < 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].
           If [x < 0] or [y < 0], the result of [Int32.rem x y] is
           not specified and depends on the platform. *)
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.
         See the documentation of the [Printf] module for more information, *)