VxWorks: Link problem

VxWorks: Link problem

[Petter Fryklund]

I get undefined reference for high123 and low123 when trying to make
VwWorks_rom including this little neat machine code: (AdaMULTI builds OK!)

with Machine_Code;
procedure rdtsc (High, Low : out Interfaces.Unsigned_32) is

   high123 : Interfaces.Unsigned_32;
   low123  : Interfaces.Unsigned_32;
   pragma Export (C, High123, "high123");
   pragma Export (C, Low123, "low123");


   procedure Do_Inline_Code is
      use Machine_Code;
   begin
      asm'(inst => "rdtsc                            ");
      asm'(inst => "movl    %eax,high123             ");
      asm'(inst => "movl    %edx,low123              ");
   end Do_Inline_Code;

begin
   Do_Inline_Code;
   High := High123;
   Low  := Low123;
end Rdtsc;

(This is done in order to get 64 bit tick counter.) Any suggestions.

Re: VxWorks: Link problem

[Ted Dennison]

"Petter Fryklund" <qsbpefr@esavionics.se> wrote in message news:<a3dt2s$t7j$1@newstoo.ericsson.se>...
> I get undefined reference for high123 and low123 when trying to make
> VwWorks_rom including this little neat machine code: (AdaMULTI builds OK!)
> procedure rdtsc (High, Low : out Interfaces.Unsigned_32) is
> 
>    high123 : Interfaces.Unsigned_32;
>    low123  : Interfaces.Unsigned_32;
>    pragma Export (C, High123, "high123");
>    pragma Export (C, Low123, "low123");

Out of curiosity, why are you exporting these? They appear to be
internal variables. I don't see what good it would be for some other
external routine to link to them. Do you actually have another routine
somewhere that tries to link against them?

I'm not sure this is legal in any event, as the variables are declared
local to a procedure, not in a global conext. They get allocated on
the stack when the routine is entered, and removed from the stack when
it exits. Thus there's no static address for external routines to bind
to. If you really want them exported, they should probably be declared
in the outer scope of a package spec or body.

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