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From: Alexander Holler <holler@ahsoftware.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] arm: wrong Relocation and not cleared BSS
Date: Sun, 31 Oct 2010 11:59:40 +0100	[thread overview]
Message-ID: <4CCD4C1C.2050603@ahsoftware.de> (raw)
In-Reply-To: <20101030143624.E6C701522C0@gemini.denx.de>

Hello,

Am 30.10.2010 16:36, schrieb Wolfgang Denk:
> Dear Albert ARIBAUD,
>
> In message<4CCC1F6C.7040603@free.fr>  you wrote:
>>
>> Wait a minute. No parts of the code assume BSS is *cleared*, or at least
>> no pat of the should *should ever* assume that. BSS is not "zeroed
>> data", it is "uninitialized data".
>
> BSS _is_ zeroed data. This is a very basic assumption of the C
> runtime.
>
>> BSS is not *required* to be zero. It is zeroed out as a courtesy, but>
>
> No, you are wrong here.
>
> Zeroing of the BSS is a mandatory requirement.


Beeing curious, I've looked up that part in the C99 standard. Just to 
refresh our memories:

-------------------------------------
6.7.8

10

If an object that has automatic storage duration is not initialized 
explicitly, its value is
indeterminate. If an object that has static storage duration is not 
initialized explicitly,
then:
? if it has pointer type, it is initialized to a null pointer;
? if it has arithmetic type, it is initialized to (positive or unsigned) 
zero;
? if it is an aggregate, every member is initialized (recursively) 
according to these rules;
? if it is a union, the ?rst named member is initialized (recursively) 
according to these
rules.
-------------------------------------

Regards,

Alexander

  reply	other threads:[~2010-10-31 10:59 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-30 13:08 [U-Boot] arm: wrong Relocation and not cleared BSS Alexander Holler
2010-10-30 13:36 ` Albert ARIBAUD
2010-10-30 13:45   ` Alexander Holler
2010-10-30 13:57     ` Albert ARIBAUD
2010-10-30 14:07       ` Alexander Holler
2010-10-30 14:39       ` Wolfgang Denk
2010-10-30 16:01         ` Albert ARIBAUD
2010-10-30 16:10           ` Wolfgang Denk
2010-10-30 14:37     ` Wolfgang Denk
2010-10-30 14:36   ` Wolfgang Denk
2010-10-31 10:59     ` Alexander Holler [this message]
2010-10-31 11:58       ` Wolfgang Denk
2010-10-31 12:21         ` Albert ARIBAUD
2010-10-31 16:18         ` Alexander Holler
2010-10-30 15:00   ` Wolfgang Denk
2010-10-30 17:21     ` Albert ARIBAUD
2010-10-30 18:01       ` Wolfgang Denk
2010-10-31  7:44     ` Heiko Schocher
2010-10-30 15:15   ` Darius Augulis
2010-10-30 16:44     ` Albert ARIBAUD
2010-10-30 20:03     ` Alexander Holler
2010-10-30 20:51       ` Alexander Holler
2010-10-31  7:47         ` Heiko Schocher
2010-11-02  5:39           ` V, Aneesh
2010-11-02  5:58             ` V, Aneesh
2010-11-02  6:32               ` Albert ARIBAUD
2010-11-02  7:18                 ` V, Aneesh
2010-11-02  7:37                   ` [U-Boot] Bad page state in process 'swapper' sywang
2010-11-02  7:44                     ` Albert ARIBAUD
2010-11-02  8:13                       ` sywang
2010-11-02  8:44                         ` Wolfgang Denk
2010-11-02  8:40                     ` Wolfgang Denk
2010-11-03  2:29                       ` sywang
2010-11-02  7:41                   ` [U-Boot] arm: wrong Relocation and not cleared BSS Albert ARIBAUD
2010-11-02  8:53                     ` V, Aneesh
2010-11-02  9:04                       ` Albert ARIBAUD
2010-10-31  7:43 ` Heiko Schocher

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