On Tue, 11 Aug 2009 16:36:31 -0700 Jonathan Adams <jonathan.ad...@sun.com> wrote:
> It's not quite like that; the issue is that the load and store > instructions in the SPARC instruction set have a signed immediate > field of 13 bits. That means that you can access an offset relative > to a register (like %fp) in the range [%fp - 4096, %fp + 4095]. > > By setting the bias to 2047, your allowable offsets move lower, so > you can access: > > [%fp + BIAS - 4096 - 2047), %fp + BIAS + (4095 - 2047)] > = [%fp + BIAS - 6143, %fp + BIAS + 2048] > I'm not sure I follow. (%fp + BIAS - 4096 - 2047) is still (%fp - 4096) because +BIAS and -2047 cancel each other out. Where do you get 6k of local storage from? > The area between %sp and %sp+BIAS is not used for anything, and has no > purpose. As far as the system is concerned, you aren't allowed to > access anything below %sp+BIAS. > Am I correct to asume that each 64-bit process' main stack has a wasted area of 2047 bytes, and NOT each function's stack frame? _______________________________________________ opensolaris-code mailing list opensolaris-code@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
