From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: Dmitry Antipov <antipov@mvista.com>, emacs-devel@gnu.org
Subject: Re: immediate strings #2
Date: Mon, 28 Nov 2011 21:07:35 -0500 [thread overview]
Message-ID: <jwvfwh7adml.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <4ED4089C.3050203@cs.ucla.edu> (Paul Eggert's message of "Mon, 28 Nov 2011 14:18:04 -0800")
> struct Data_Lisp_String
> {
> unsigned int immediate_bit : 1;
> signed int : IMMEDIATE_STRING_LENGTH_BITS; /* padding for immediate size */
> unsigned int gcmarkbit : 1;
> signed int : IMMEDIATE_STRING_LENGTH_BITS; /* and for immediate size_byte */
> INTERVAL intervals;
> ptrdiff_t size;
> ptrdiff_t size_byte;
> unsigned char *data;
> };
Why? IIUC that sums up to 5x32bit, which will break the "multiple of
8 alignment" rule and hence will need to be be rounded up to 6x32bit,
for an overall increase of 50% in the size of struct Lisp_String.
I.e. a non-starter. There are bits available in size and size_byte, we
have to use those (like we currently do with gcmarkbit in `size').
Stefan
next prev parent reply other threads:[~2011-11-29 2:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-28 9:11 immediate strings #2 Dmitry Antipov
2011-11-28 17:33 ` Stefan Monnier
2011-11-28 19:48 ` Ken Raeburn
2011-11-28 20:10 ` Andreas Schwab
2011-11-28 21:54 ` Stefan Monnier
2011-11-28 22:25 ` Andreas Schwab
2011-11-29 0:57 ` Ken Raeburn
2011-11-29 8:44 ` Andreas Schwab
2011-11-29 15:48 ` Ken Raeburn
2011-11-29 16:08 ` Andreas Schwab
2011-11-30 16:43 ` Ken Raeburn
2011-11-28 22:18 ` Paul Eggert
2011-11-29 2:07 ` Stefan Monnier [this message]
2011-11-29 3:37 ` Dmitry Antipov
2011-11-29 8:50 ` Paul Eggert
2011-11-30 5:37 ` Dmitry Antipov
2011-11-30 9:35 ` Paul Eggert
2011-11-30 16:43 ` Ken Raeburn
2011-11-30 21:44 ` Paul Eggert
2011-11-29 3:17 ` Dmitry Antipov
2011-11-29 5:29 ` Dmitry Antipov
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