Re: Issue with allocating stack space to local variables (frame pointer)

["Sivaprasad.pv" <sivaprasad dot pv at redpinesignals dot com>]

Ian,

Thanks for your quick reply.
In our case inorder to push some value onto the stack , it place the 
value into the location pointed by stack pointer first and then 
decrement/increment the stack pointer (post operation).
jump to sub- routine & return instructions are implemented  using above 
method.
Initially our stack is bottom-up stack,currently we want to change it to 
top-down stack.
Is it possible to do this in compiler with out changing our ISA( 
instruction set architecture).

Thanks & regards,
Siva Prasad.

Ian Lance Taylor wrote:
> "Sivaprasad.pv" <sivaprasad.pv@redpinesignals.com> writes:
>
>   
> > We are trying to port gnu gcc for our custom processor. But it is
> > giving problem for allocating stack to local (auto) variables.
> > for example:
> >     I declared  local variable in  following order.
> >                     int a, b, c;
> >                     char d;
> >                     short e, f, g;
> >                      char  h;
> > while allocating stack to these local variable it is leaving space
> > which is equal to the size of that data type.
> >     
>
> That sounds like exactly what it is supposed to do, so I think you
> need to explain in more detail.
>
>
>   
> > I have tried to adjust  by defining "STARTING_FRAME_OFFSET" macro.But
> > I am unable to get required results.
> >     
>
> Setting STARTING_FRAME_OFFSET to any value other than zero is almost
> certainly wrong.  If you are looking at STARTING_FRAME_OFFSET, you
> should probably instead look at INITIAL_ELIMINATION_OFFSET.
>
> Ian
>
>
>