From: Jeffrey A Law <law@cygnus.com>
To: Matthew Wilcox <Matthew.Wilcox@genedata.com>
Cc: Grant Grundler <grundler@cup.hp.com>, parisc-linux@thepuffingroup.com
Subject: Re: [parisc-linux] Anyone got a few moments?
Date: Mon, 28 Jun 1999 11:47:56 -0600 [thread overview]
Message-ID: <17559.930592076@upchuck.cygnus.com> (raw)
In-Reply-To: Your message of Mon, 28 Jun 1999 19:34:04 +0200. <19990628193404.I30362@mencheca.ch.genedata.com>
In message <19990628193404.I30362@mencheca.ch.genedata.com>you write:
> > What does xchg() do?
>
> /*
> * Atomic [test&set] exchange
> *
> * void *xchg_u32(void *ptr, unsigned long val)
> * Changes the memory location '*ptr' to be val and returns
> * the previous value stored there.
> */
>
tsk tsk, that is a highly non-portable API for atomic operations.
> It's atomic with respect to interrupts and other CPUs.
>
> PA-RISC 2.0 seems to have LDC{W,D}, but that's going to make implementation
> a real pain.
Yes. Major pain since the only useful atomic operations are load & clear
word/double as you noted.
Why does linux want an "exchange"-like API for atomic operations? That
just seems totally weird and stupid.
jeff
next prev parent reply other threads:[~1999-06-28 18:15 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-06-28 15:21 [parisc-linux] Anyone got a few moments? Matthew Wilcox
1999-06-28 17:09 ` Grant Grundler
1999-06-28 17:34 ` Matthew Wilcox
1999-06-28 17:47 ` Jeffrey A Law [this message]
1999-06-28 18:10 ` Matthew Wilcox
1999-06-28 18:37 ` Alan Cox
1999-06-28 19:00 ` Matthew Wilcox
1999-06-28 19:12 ` Alan Cox
1999-06-28 18:39 ` Alan Cox
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