David Miller writes: > From: Mikael Pettersson <mikpe@xxxxxxxx> > Date: Tue, 18 Dec 2007 13:06:55 +0100 > > > My main question is: what does the kernel do to the > > high 32 bits of the 64-bit integer registers during > > context switches? > > Only %oX and %gX registers have the full 64-bit preserved across > context switches for 32-bit processes. > > The %lX and %iX registers cannot have their full 64-bits preserved > because the amount of save space is fixed by the register window save > area layout on the stack, which only saves 32-bit values for each > register. >> Also, does anyone know what Solaris does to the >> high 32 bits during context switches? > >Solaris handles things identically to Linux. > >These rules are even encoded into places like the >GCC backend for sparc, when generating v9 code >for 32-bit. Thanks, this helps. /Mikael - To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
