From: Andreas Schwab <schwab@linux-m68k.org>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>, linux-m68k@lists.linux-m68k.org
Subject: Re: clear_bit_unlock_is_negative_byte
Date: Sat, 22 Jul 2023 08:24:34 +0200 [thread overview]
Message-ID: <87edl0lazh.fsf@linux-m68k.org> (raw)
In-Reply-To: <2e4c5eda-671e-9fc8-17fc-7f4b894ef653@gmail.com> (Michael Schmitz's message of "Fri, 21 Jul 2023 13:43:06 +1200")
On Jul 21 2023, Michael Schmitz wrote:
> static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr,
> volatile unsigned long *p)
> {
> unsigned char *cp = (unsigned char *) p;
> char result;
> char mask = 1 << nr; /* nr guaranteed to be < 7 */
>
> __asm__ __volatile__ ("eori.b %1, %2; smi %0"
> : "=d" (result)
> : "i" (mask), "o" (*(cp+3))
That should use "id" as constraint, so that the compiler can share the
constant with other insns. Also, the third operand is modified, so it
needs to be marked as in/out.
--
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."
next prev parent reply other threads:[~2023-07-22 6:24 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 ` Andreas Schwab [this message]
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 ` clear_bit_unlock_is_negative_byte Andreas Schwab
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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