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From: "Daryl Van Vorst" <daryl@wideray.com>
To: "'BlueZ Mailing List'" <bluez-devel@lists.sourceforge.net>
Subject: [Bluez-devel] Alignment issue
Date: Tue, 10 Aug 2004 11:38:25 -0700	[thread overview]
Message-ID: <001301c47f09$3900e650$1301010a@baked> (raw)

Marcel,

I ran into an alignment problem on our ARM platform. It showed up as =
corrupt
SDP responses. I traced it back to bt_put_unaligned() in bluetooth.h

The attached patch should fix the problem (it does as far as I can =
tell).
The compiler probably thinks both arguments to memcpy() are aligned and =
so
makes an optimization which breaks the copy (because the destination is =
not
actually aligned). Perhaps this is a compiler bug... I'm using gcc =
3.3.3.
After googling and reading some discussion on the topic it seems that =
it's
probably not a compiler bug. I'll leave that for someone else to decide. =
:)

I know I'm behind on the libs version, but I just had a look in CVS and =
the
code in question is the same.

Look reasonable to you?

Regards,

-Daryl.

--- bluez-libs-2.8/include/bluetooth.h	2004-07-07 21:54:33.000000000 =
-0700
+++ bluez-libs-2.8_mod/include/bluetooth.h	2004-08-09
11:27:04.000000000 -0700
@@ -93,10 +93,14 @@
 #define bt_put_unaligned(val, ptr) ((void)( *(ptr) =3D (val) ))
 #else
 #define bt_get_unaligned(ptr) \
-	({ __typeof__(*(ptr)) __tmp; memcpy(&__tmp, (ptr), sizeof(*(ptr)));
__tmp; })
+	({ __typeof__(*(ptr)) __tmp; \
+	char *__tmp1 =3D (char *)(ptr); \
+	memcpy(&__tmp, __tmp1, sizeof(*(ptr))); \
+	__tmp; })
 #define bt_put_unaligned(val, ptr) \
 	({ __typeof__(*(ptr)) __tmp =3D (val); \
-	memcpy((ptr), &__tmp, sizeof(*(ptr))); \
+	char *__tmp1 =3D (char *)(ptr); \
+	memcpy(__tmp1, &__tmp, sizeof(*(ptr))); \
 	(void)0; })
 #endif
=20



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             reply	other threads:[~2004-08-10 18:38 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-10 18:38 Daryl Van Vorst [this message]
2004-08-10 23:12 ` [Bluez-devel] Alignment issue Marcel Holtmann
2004-08-11  9:20   ` Stephen Crane
2004-08-11 11:08     ` David Woodhouse
2004-08-11 19:33       ` Marcel Holtmann
2004-08-11  7:13 ` Marcel Holtmann
2004-08-11 16:44   ` Daryl Van Vorst
2004-08-11 19:31     ` Marcel Holtmann
2004-08-12  8:34       ` David Woodhouse
2004-08-12  9:27         ` Marcel Holtmann
2004-08-12 10:01           ` David Woodhouse
2004-08-12 10:22             ` Marcel Holtmann
2004-08-12 10:35               ` David Woodhouse
2004-08-12 11:00                 ` Marcel Holtmann
2004-08-12 11:33                   ` David Woodhouse
2004-08-12 11:49                     ` Marcel Holtmann
2004-08-12 12:02                       ` David Woodhouse
2004-08-12 12:29                         ` Marcel Holtmann
2004-08-12 13:36                         ` Marcel Holtmann
2004-08-13  8:07                           ` David Woodhouse
2004-08-13  9:05                             ` Marcel Holtmann
2004-08-13  9:14                               ` David Woodhouse
2004-08-13 11:52                               ` David Woodhouse
2004-08-13 12:40                                 ` Marcel Holtmann
2004-08-12 12:53               ` David Woodhouse
2004-08-13  9:58                 ` Marcel Holtmann
2004-08-13 10:56                   ` David Woodhouse
2004-08-12 10:10           ` Stephen Crane
2004-08-12 10:25             ` Marcel Holtmann
2005-01-20 14:30   ` David Woodhouse
2005-01-20 14:45     ` Marcel Holtmann
2005-01-20 14:59       ` David Woodhouse
2005-01-20 18:14         ` Marcel Holtmann
2005-01-21  8:26           ` David Woodhouse
2005-01-23  8:12             ` Marcel Holtmann
2005-01-23 11:39         ` Marcel Holtmann
2005-01-23 12:29           ` David Woodhouse
2005-01-23 14:40             ` Marcel Holtmann
2005-01-23 15:11               ` David Woodhouse
2005-01-23 15:22                 ` Marcel Holtmann
2005-01-23 23:16                   ` David Woodhouse
  -- strict thread matches above, loose matches on Subject: below --
2004-08-16  9:48 john smith
2004-08-16 10:15 ` Marcel Holtmann

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