From: Wojciech Kromer <krom@dgt-lab•com.pl>
To: "Linuxppc-Embedded (E-mail)" <linuxppc-embedded@lists•linuxppc.org>
Subject: Re: need a fast byteorder changing routine
Date: Fri, 18 Jul 2003 08:26:34 +0200 [thread overview]
Message-ID: <3F17931A.4000405@dgt-lab.com.pl> (raw)
In-Reply-To: <Xx969281867387.18796@webmail1.inner-21cn.com>
Użytkownik li napisał:
>Hi all,
>i need do a lot of byteorder changing operation from big-endian to little-endian. cpu_to_le32 is not fast enough for me, does anyone have such a routine written in asm.?
>PS: here is an ugly asm function do such thing:
>void swapbyte(unsigned long *val, unsigned long offset,
> unsigned long value)
>{
>
> asm ("lis 3 %0@ha" : "=r" (val));
> asm ("lwz 3,%0@l(3)" : "=r" (val));
> asm ("stw %1, 0(4)" : "=r" (offset));
> asm ("stw %2, 0(5)" : "=r" (value));
> asm ("stwbrx 5, 3, 4");
>}val is the address of value. i used to set this function as inline, but kernel said:
>Oops: kernel access of bad area, sig: 11
>Any comments
>Best Regards!
>Li
>
>
>
>
>
try DIRECT using out_le16/32 in_le16/32 from <asm/io.h>,
this takes same time as one big endian write/read
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next parent reply other threads:[~2003-07-18 6:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Xx969281867387.18796@webmail1.inner-21cn.com>
2003-07-18 6:26 ` Wojciech Kromer [this message]
2003-07-18 13:03 need a fast byteorder changing routine Wells, Charles
-- strict thread matches above, loose matches on Subject: below --
2003-07-18 13:24 Wells, Charles
2003-07-18 14:35 ` Peter Barada
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