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Re: [Caml-list] Runtime overflow and what to do
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Date: -- (:)
From: Xavier Leroy <xavier.leroy@i...>
Subject: Re: [Caml-list] Runtime overflow and what to do
> [Overflow checking in integer multiplication]

> (* [lenght_of_int] is the maximum number of bits in an integer. *)
> let length_of_int = Sys.word_size - 2;;
> 
> let ( * ) n m =
>  if num_bits_int n + num_bits_int m < length_of_int
>  then n * m else raise (Overflow ("*", string_of_int n, string_of_int m))
> 
> (* [num_bits_int n] returns the number of significant bits of an
>    integer. *)

Hmmph... this definition raises Overflow when computing
min_int * 1, or (min_int / 2) * 2, while these products are actually
representable within a machine integer...

Apologies for nit-picking; I couldn't resist!

- Xavier Leroy
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