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[Caml-list] Bug? Printf, %X and negative numbers
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| Date: | -- (:) |
| From: | Claude Marche <Claude.Marche@l...> |
| Subject: | Re: [Caml-list] Bug? Printf, %X and negative numbers |
>>>>> "Brian" == Brian Hurt <brian.hurt@qlogic.com> writes:
Brian> $ ocaml
Brian> Objective Caml version 3.06
Brian> # Printf.printf "%08X\n" (1 lsl 30);;
Brian> C0000000
Brian> - : unit = ()
Brian> # Printf.printf "%010X\n" (1 lsl 30);;
Brian> 00C0000000
Brian> - : unit = ()
Brian> #
Brian> I expected output of 40000000, not C0000000. Note that this isn't a case
Brian> of simple sign extension, as the second example demonstrates. Where'd the
Brian> extra bit come from?
Sorry to come back at the very beginning of this thread, but I'd like
to add my two centeuros: I feel that the first answer is correct, but
the second is wrong. Why? (1 lsl 30) is -2^30, right ? and the format
"%nX" means the hexadecimal 2-complement representation of the
argument, on n hexdigits, right ? So I think
Printf.printf "%08X\n" (1 lsl 30);;
should write C0000000 and
Printf.printf "%010X\n" (1 lsl 30);;
should write FFC0000000.
--
| Claude Marché | mailto:Claude.Marche@lri.fr |
| LRI - Bât. 490 | http://www.lri.fr/~marche/ |
| Université de Paris-Sud | phoneto: +33 1 69 15 64 85 |
| F-91405 ORSAY Cedex | faxto: +33 1 69 15 65 86 |
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