VxWorks: Link problem

["Petter Fryklund" <qsbpefr@esavionics.se>]

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.