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From: "Luke A. Guest" <laguest@archeia.com>
Newsgroups: comp.lang.ada
Subject: Re: Using pointers with inline assembly in Ada
Date: Fri, 10 Jun 2022 12:16:27 +0100
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On 10/06/2022 06:24, Rod Kay wrote:
> On 10/6/22 07:30, NiGHTS wrote:
>> declare
>>           type ff is array (0 .. 10) of Unsigned_32;
>>           pragma Pack(ff);
>>           Flags : aliased ff := (others => 0);
>>           Flag_Address : System.Address := Flags'Address;
>> begin
>>          Asm (   "movl %0, %%eax" &
>>                  "movl $1, (%%eax)" ,
>>                  Inputs   => System.Address'Asm_Input ("g", 
>> Flag_Address),
>>                  Clobber  => "eax",
>>                  Volatile => true
>>          );
>>          Put_Line ("Output:" & Flags(0)'Img);
>> end;
>>
> 
>     If you are on a 64 bit machine, then I expect 'pragma Pack' might be 
> the problem, as 2 consecutive array elements will fir into a single 
> address.
> 
> 
>     Also, possibly use ...
> 
>     Flag_Address : System.Address := Flags (Flags'First)'Address;
> 
> 
> Regards.

Dump the xpanded (generated code) and the assembly from gnat.