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From: Andreas Schwab <schwab@linux-m68k.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-m68k@lists.linux-m68k.org
Subject: Re: clear_bit_unlock_is_negative_byte
Date: Fri, 21 Jul 2023 08:34:55 +0200	[thread overview]
Message-ID: <87jzut6acw.fsf@linux-m68k.org> (raw)
In-Reply-To: <ZLmKq2VLjYGBVhMI@casper.infradead.org> (Matthew Wilcox's message of "Thu, 20 Jul 2023 20:27:39 +0100")

On Jul 20 2023, Matthew Wilcox wrote:

> +static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr,
> +               volatile unsigned long *p)
> +{
> +       char result;
> +       char mask = 1 << nr;    /* nr guaranteed to be < 7 */
> +
> +       __asm__ __volatile__ ("eori %1, %2; smi %0"

Why are you using XOR if you want to clear a bit?  If it operates on a
byte, why does it receive a pointer to long?

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

  parent reply	other threads:[~2023-07-21  6:41 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-20 19:27 clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-20 22:37 ` clear_bit_unlock_is_negative_byte Michael Schmitz
2023-07-21  1:12   ` clear_bit_unlock_is_negative_byte Michael Schmitz
2023-07-21  1:32     ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-21  1:43       ` clear_bit_unlock_is_negative_byte Michael Schmitz
2023-07-21 17:03         ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-21 22:07           ` clear_bit_unlock_is_negative_byte Michael Schmitz
2023-07-22  6:24         ` clear_bit_unlock_is_negative_byte Andreas Schwab
2023-07-22 14:45           ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-22 15:26             ` clear_bit_unlock_is_negative_byte Andreas Schwab
2023-07-22 15:38               ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-21  6:34 ` Andreas Schwab [this message]
2023-07-21  8:57   ` clear_bit_unlock_is_negative_byte Brad Boyer
2023-07-21  9:18     ` clear_bit_unlock_is_negative_byte Andreas Schwab
2023-07-21 11:59   ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-21 12:52     ` clear_bit_unlock_is_negative_byte Andreas Schwab
2023-07-21 20:29     ` clear_bit_unlock_is_negative_byte Brad Boyer
2023-07-22  3:42       ` clear_bit_unlock_is_negative_byte Matthew Wilcox
2023-07-22 23:49         ` clear_bit_unlock_is_negative_byte Brad Boyer
2023-07-23  1:08           ` clear_bit_unlock_is_negative_byte Michael Schmitz

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