On Tuesday 21 March 2006 14:57, Richard Henderson wrote: > On Mon, Mar 20, 2006 at 04:03:08PM -0000, Dave Korn wrote: > > Do you happen to know off the top of your head when get_frame_size() > > becomes valid? > > You don't get a good first-pass estimate until after all rtl > generation has been done. Which is later than you need. > > Another possibility is to allocate an extra word high in the > stack frame for temporary storage in large frames w/ sibcalls > to functions using all arguments. Then you'd deallocate in > several steps: > > scratchslot = argument > argument = stack frame size - small > sp += argument > argument = scratchslot > sp += small
This assumes you have a frame pointer or sp+large_offset addressing mode for accessing scratchslot. In which case you could either use fp as scratch storage or probably have an add sp, large_offset instruction. Paul
