Date: Sat, 13 Mar 1999 15:09:06 -0800 (PST) From: Chris Costello <chris@dei.calldei.com> To: Dennis <dennis@etinc.com> Cc: hackers@FreeBSD.ORG Subject: Re: 'C' language question Message-ID: <Pine.BSI.4.05L.9903131507460.14551-100000@dei.calldei.com> In-Reply-To: <199903132232.RAA19255@etinc.com>
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On Sat, 13 Mar 1999, Dennis wrote:
>
> I have a memory mapped controller that requires that all of its
> register reads and writes be 32 bits....the follow code:
>
> *reg |= 0x80000000;
>
> generates a byte OR (ORB instruction) which trashes the register with
> gcc 2.9.2....a stupid "optimization" that happens to be wrong in this
> case.
>
> is there a declaration that will force the compiler to generate a 32bit
> OR (ORL instruction) on this?
>
Try using the 'asm { ... }' syntax in C. (of course, this is where your
code becomes platform-specific...)
> Dennis
>
>
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