On Sun, Aug 21, 2011 at 19:42, Thomas Schilling <nominolo@googlemail.com> wrote:
On 16 August 2011 15:39, Johan Tibell <johan.tibell@gmail.com> wrote:
> the CPU masks out the
> last 5 bits in the shift amount and only uses those when shifting

As an aside, this may be how it's specified now in all modern x86(-64)
CPUs, but it definitely wasn't true for all CPUs.  Some older x86 CPUs
actually would set the value to zero if the shift amount was greater
than the word length.  (I'm not sure which, but may have been
different in early 386 CPUs and Athlon CPUs.)

FWIW I vaguely recall a bit of an outcry when this changed on Intel CPUs.  It may have been around the 80486. 

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