From: Stefan Monnier <monnier@iro.umontreal.ca>
To: emacs-devel@gnu.org
Subject: Re: [PATCH]: Add new bytecode op `switch' for implementing branch tables.
Date: Fri, 10 Feb 2017 10:12:02 -0500 [thread overview]
Message-ID: <jwvh942ulny.fsf-monnier+gmane.emacs.devel@gnu.org> (raw)
In-Reply-To: CA+T2Sh17+ERVVnGfJJGKMRu4gmj1aET1kRoVErdfUsDTAw-Y0g@mail.gmail.com
>>> 1. For jump tables, HASH_TABLE_SIZE (h) == h->count, so using h->count
>>> directly saves the cost of an array lookup.
>> That doesn't invalidate the usefulness of a linear search.
> Sure, but that makes it better (IMO) to have separate code for linear
> searching the jump table.
You mean to have a copy of the search in bytecode.c? I guess that's
fine, I'm talking about the behavior of `gethash` only.
>> The linear search should compare HASH_HASH(h, i) to the search key's
>> hash anyway, so this comparison against nil is not needed.
> Is that strictly needed, though?
No, it's an optimisation to avoid calling Fequal unnecessarily.
Stefan
next prev parent reply other threads:[~2017-02-10 15:12 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-06 17:50 [PATCH]: Add new bytecode op `switch' for implementing branch tables Vibhav Pant
2017-02-06 18:30 ` Stefan Monnier
2017-02-07 8:45 ` Vibhav Pant
2017-02-07 14:41 ` Stefan Monnier
[not found] ` <CA+T2Sh3N09WGoHtNL3BbptsKA1ZdwWedTNDd0vmeBe0fTO5a1g@mail.gmail.com>
[not found] ` <CA+T2Sh2sa6=WOvyePzL_ACR0Nw=jTnZze_xXFcvL=22OURP=ZA@mail.gmail.com>
2017-02-07 15:21 ` Vibhav Pant
2017-02-07 13:50 ` Vibhav Pant
2017-02-07 15:56 ` Clément Pit-Claudel
2017-02-08 13:38 ` Vibhav Pant
2017-02-08 16:21 ` Vibhav Pant
2017-02-08 17:46 ` Vibhav Pant
2017-02-09 13:21 ` Stefan Monnier
2017-02-08 17:56 ` Eli Zaretskii
2017-02-23 4:35 ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase [was: Add new bytecode op `switch' for implementing branch tables.] Tino Calancha
2017-02-23 8:36 ` Richard Copley
2017-02-23 10:12 ` Tino Calancha
2022-07-04 12:24 ` Vibhav Pant
2017-02-23 13:39 ` Stefan Monnier
2017-02-23 14:33 ` Kaushal Modi
2017-02-23 15:10 ` Stefan Monnier
2022-07-02 20:31 ` Robert Weiner
2022-07-02 21:28 ` Stefan Monnier
[not found] ` <CA+T2Sh29UhuNrhRZG=PPQbYYHtONXwyb8dX4rBVLmwdORLELhg@mail.gmail.com>
2017-02-23 17:50 ` Vibhav Pant
2017-04-11 17:40 ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase Lars Brinkhoff
2017-02-23 16:15 ` Compiled code in Emacs-26 will fail in Emacs-25 if use pcase [was: Add new bytecode op `switch' for implementing branch tables.] raman
2017-02-23 17:24 ` Drew Adams
2017-02-23 17:50 ` T.V Raman
2017-02-23 18:02 ` Drew Adams
2017-02-23 18:24 ` T.V Raman
2017-02-23 19:00 ` Drew Adams
2017-02-24 2:06 ` defsubst VS defun or defmacro [was RE: Compiled code in Emacs-26 will fail in Emacs-25 if use pcase] Tino Calancha
2017-02-24 3:14 ` Eric Abrahamsen
2017-02-24 3:56 ` raman
2017-02-24 4:20 ` Eric Abrahamsen
2017-02-24 3:51 ` raman
2017-02-09 17:32 ` [PATCH]: Add new bytecode op `switch' for implementing branch tables Clément Pit-Claudel
2017-02-09 19:15 ` Clément Pit-Claudel
2017-02-10 4:12 ` Vibhav Pant
2017-02-10 4:17 ` Clément Pit-Claudel
2017-02-10 5:03 ` Vibhav Pant
2017-02-10 6:07 ` Stefan Monnier
2017-02-10 13:51 ` Vibhav Pant
2017-02-10 15:12 ` Stefan Monnier [this message]
2017-02-10 17:59 ` Vibhav Pant
2017-02-10 18:25 ` Vibhav Pant
2017-02-10 20:47 ` Paul Eggert
2017-02-10 20:58 ` Stefan Monnier
2017-02-11 15:07 ` Vibhav Pant
2017-02-12 3:10 ` Vibhav Pant
2017-02-13 7:18 ` Vibhav Pant
2017-02-09 16:37 ` Vibhav Pant
2017-02-06 19:32 ` Eli Zaretskii
2017-02-07 14:26 ` Vibhav Pant
2017-02-07 16:14 ` Eli Zaretskii
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