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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: avoiding builtin memset
Date: Thu, 27 Apr 2017 08:09:12 +0100
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Xref: news.eternal-september.org comp.lang.ada:46640
Date: 2017-04-27T08:09:12+01:00
List-Id: <comp.lang.ada>

"J-P. Rosen" <rosen@adalog.fr> writes:

> Le 27/04/2017 à 02:22, Jere a écrit :
>>> 	For Element of Memory loop
>>> 	    Element := Value;
>>> 	end loop;
>>
>> I'll be honest, I wasn't expecting it to avoid memset (didn't see why
>> it should), but it didn't recursively call it.  It did however, do a
>> very interesting loop unroll:
>> [...]
> What if you replace the loop with:
>    Memory := (others => Value);

That's when the generated code calls memset(3). Unless, I guess, you've
set System up to forbid composite assignments?

I changed my (Cortex) system.ads to

   Support_Aggregates        : constant Boolean := False;

and this code

      --  Initialize BSS in SRAM
      Bss := (others => 0);

results in

startup.adb:113:14: aggregate not supported by configuration

whereas system.ads:

   Support_Composite_Assign  : constant Boolean := False;

results in

startup.adb:113:11: composite assignment not supported by configuration