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From: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RFC][PATCH] Code Clean-up (weak functions)
Date: Thu, 25 Dec 2008 09:56:37 +0900	[thread overview]
Message-ID: <4952DA45.3000805@necel.com> (raw)
In-Reply-To: <3efb10970812241141x3e885bfakd74f631bc710b726@mail.gmail.com>

Remy Bohmer wrote:
> Create a default fallback routine that can be used if there is no
> strong implementation:
> -------------------------------------------------------------------------------------------
> __attribute__((weak)) unsigned long long printk_clock(void)
> {
>         return sched_clock();
> }
> -------------------------------------------------------------------------------------------
> and here is an example of the strong implementation (from the ARM architecture):
> -------------------------------------------------------------------------------------------
> unsigned long long printk_clock(void)
> {
>         return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
>                         (1000000000 / HZ);
> }
> -------------------------------------------------------------------------------------------
> 
> If the strong implementation is available, the weak is simply
> discarded during linking, if the strong is omitted, the weak is used
> as fallback. This is a clean, lean and mean example without
> complex/superfluous aliases or checks for NULL pointers.
> It should not get any harder than this...

+1.  I like this one, and U-Boot/MIPS _machine_restart() is implemented
in the same manner.

-- 
Shinya Kuribayashi
NEC Electronics

  reply	other threads:[~2008-12-25  0:56 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-13  5:26 [U-Boot] [RFC][PATCH] Code Clean-up (weak functions) Graeme Russ
2008-12-13 22:48 ` Remy Bohmer
2008-12-14  9:23   ` Graeme Russ
2008-12-22  9:05 ` Mike Frysinger
2008-12-22  9:16   ` Graeme Russ
2008-12-22 11:44     ` Mike Frysinger
2008-12-22 11:20       ` Graeme Russ
2008-12-23  4:18         ` Mike Frysinger
2008-12-24  1:14 ` Shinya Kuribayashi
2008-12-24 14:12   ` Joakim Tjernlund
2008-12-24 16:55     ` Shinya Kuribayashi
2008-12-24 19:41       ` Remy Bohmer
2008-12-25  0:56         ` Shinya Kuribayashi [this message]
2008-12-25 11:26           ` Graeme Russ
2008-12-25 14:00       ` Joakim Tjernlund
2008-12-25 14:39         ` Shinya Kuribayashi
2008-12-25 11:22   ` Graeme Russ

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