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(* SPDX-License-Identifier: Apache-2.0 *)
(* Copyright 2017 WebAssembly Community Group participants *)
(* This file is originally from the WebAssembly reference interpreter available at https://github.com/WebAssembly/spec/tree/main/interpreter *)
(* SPDX-License-Identifier: MIT *)
(* Copyright (c) 2016--2024 Jane Street Group, LLC <opensource-contacts@janestreet.com> *)
(* The code of the `popcnt` function is originally from the `base` library available at https://github.com/janestreet/base *)
(* SPDX-License-Identifier: AGPL-3.0-or-later *)
(* Copyright © 2021-2024 OCamlPro *)
(* Modified by the Owi programmers *)
include Prelude.Int32
let clz n = of_int (Ocaml_intrinsics.Int32.count_leading_zeros n)
let ctz n = of_int (Ocaml_intrinsics.Int32.count_trailing_zeros n)
(* Taken from Base *)
let popcnt =
let mask = 0xffff_ffffL in
fun [@inline] x ->
Int64.to_int32 (Int64.popcnt (Int64.logand (Int64.of_int32 x) mask))
let of_int64 = Int64.to_int32
let to_int64 = Int64.of_int32
(* Unsigned comparison in terms of signed comparison. *)
let cmp_u x op y = op (add x min_int) (add y min_int)
let eq (x : int32) y = equal x y
let ne (x : int32) y = compare x y <> 0
let lt (x : int32) y = compare x y < 0
let gt (x : int32) y = compare x y > 0
let le (x : int32) y = compare x y <= 0
let ge (x : int32) y = compare x y >= 0
let lt_u x y = cmp_u x lt y
let le_u x y = cmp_u x le y
let gt_u x y = cmp_u x gt y
let ge_u x y = cmp_u x ge y
(* If bit (32 - 1) is set, sx will sign-extend t to maintain the
* invariant that small ints are stored sign-extended inside a wider int. *)
let sx x =
Int64.to_int32
@@ Int64.shift_right (Int64.shift_left (Int64.of_int32 x) 32) 32
(* We don't override min_int and max_int since those are used
* by other functions (like parsing), and rely on it being
* min/max for int32 *)
(* The smallest signed |32|-bits int. *)
let low_int = shift_left minus_one 31
(* The largest signed |32|-bits int. *)
let high_int = logxor low_int minus_one
(* WebAssembly's shifts mask the shift count according to the 32. *)
let shift f x y = f x (to_int (logand y 31l))
let shl x y = sx (shift shift_left x y)
let shr_s x y = shift shift_right x y
let shr_u x y = sx (shift shift_right_logical x y)
let rotl x y =
let n = logand y 31l in
logor (shl x n) (shr_u x (sub 32l n))
let rotr x y =
let n = logand y 31l in
logor (shr_u x n) (shl x (sub 32l n))
let extend_s n x =
let shift = 32 - n in
shift_right (shift_left x shift) shift
(* String conversion that allows leading signs and unsigned values *)
let require b = if not b then Log.err "of_string (int32)"
let dec_digit = function
| '0' .. '9' as c -> Char.code c - Char.code '0'
| _ -> Log.err "of_string"
let hex_digit = function
| '0' .. '9' as c -> Char.code c - Char.code '0'
| 'a' .. 'f' as c -> 0xa + Char.code c - Char.code 'a'
| 'A' .. 'F' as c -> 0xa + Char.code c - Char.code 'A'
| _ -> Log.err "of_string"
let max_upper = unsigned_div minus_one 10l
let max_lower = unsigned_rem minus_one 10l
let sign_extend i =
let sign_bit = logand (of_int (1 lsl (32 - 1))) i in
if eq sign_bit zero then i
else
(* Build a sign-extension mask *)
let sign_mask = shift_left minus_one 32 in
logor sign_mask i
let of_string_exn s =
let len = String.length s in
let rec parse_hex i num =
if i = len then num
else if Char.equal s.[i] '_' then parse_hex (i + 1) num
else
let digit = of_int (hex_digit s.[i]) in
require (le_u num (shr_u minus_one (of_int 4)));
parse_hex (i + 1) (logor (shift_left num 4) digit)
in
let rec parse_dec i num =
if i = len then num
else if Char.equal s.[i] '_' then parse_dec (i + 1) num
else
let digit = of_int (dec_digit s.[i]) in
require (lt_u num max_upper || (eq num max_upper && le_u digit max_lower));
parse_dec (i + 1) (add (mul num 10l) digit)
in
let parse_int i =
require (len - i > 0);
if i + 2 <= len && Char.equal s.[i] '0' && Char.equal s.[i + 1] 'x' then
parse_hex (i + 2) zero
else parse_dec i zero
in
require (len > 0);
let parsed =
match s.[0] with
| '+' -> parse_int 1
| '-' ->
let n = parse_int 1 in
require (ge (sub n one) minus_one);
neg n
| _ -> parse_int 0
in
let parsed = sign_extend parsed in
require (le low_int parsed && le parsed high_int);
parsed
let of_string s = try Some (of_string_exn s) with _ -> None