Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: comp.arch.embedded
Subject: Re: Speaking of Multiprocessing...
Date: Thu, 23 Mar 2017 16:26:46 -0700
Organization: A noiseless patient Spider
Lines: 17
Message-ID: <ob1leb$v25$1@dont-email.me>
References: <ob1ij7$jja$1@dont-email.me> <rtKdndLJ5_hkyknFnZ2dnUU7-UednZ2d@giganews.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 23 Mar 2017 23:23:56 -0000 (UTC)
Injection-Info: mx02.eternal-september.org; posting-host="cb404ee80a6293ce4999858a69f08f0b"; logging-data="31813"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18btSivhV8VQnGdtCootgVZ"
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:45.0) Gecko/20100101 Thunderbird/45.4.0
In-Reply-To: <rtKdndLJ5_hkyknFnZ2dnUU7-UednZ2d@giganews.com>
Cancel-Lock: sha1:J1/W2ZHX66LDvrEYTEmS/EYpbQs=
Xref: csiph.com comp.arch.embedded:26182

On 3/23/2017 4:19 PM, Tim Wescott wrote:
> On Thu, 23 Mar 2017 18:38:13 -0400, rickman wrote:
>
>> I recall a discussion about the design of an instruction set
>> architecture where someone was saying an instruction was required to
>> test and set a bit or word as an atomic operation if it was desired to
>> support multiple processors.  Is this really true?  Is this a function
>> that can't be emulated with other operations including the disabling of
>> interrupts?
>
> AFAIK as long as you surround your "test and set" with an interrupt
> disable and an interrupt enable then you're OK.  At least, you're OK
> unless you have a processor that treats interrupts really strangely.

Rethink that for the case of SMP...  (coincidentally, "Support Multiple
Processors"  :> )