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From: Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Forcing GNAT to use 32-bit load/store instructions on ARM?
Date: Tue, 01 Jul 2014 10:28:38 -0700
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Date: 2014-07-01T10:28:38-07:00
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On 07/01/2014 05:06 AM, Simon Clubley wrote:
>
> The issue here is that Pragma Atomic should have given him the guarantee
> he needs.

I think I agree with Holsti that the lack of reference to the other 30 bits 
results in the compiler concluding that it can satisfy the pragma with 8-bit 
loads and stores.

> There is a place for specific assembly language insertions (for example,
> on ARM when you need to access the CPSR register), but that should not
> be required here.

A machine-code insertion seems to be required to obtain the machine-code 
instructions he desires with the type definition he is using. Generally one 
wants to define the reserved fields so one can control what values they have, 
but if he doesn't want to do that, he'll probably need a machine-code insertion.

-- 
Jeff Carter
"C++ is like giving an AK-47 to a monk, shooting him
full of crack and letting him loose in a mall and
expecting him to balance your checking account
'when he has the time.'"
Drew Olbrich
52