At 08:35 AM 9/8/2010 -0600, you wrote: >On Sep 8, 2010, at 05:39, robin wrote: > >> From: "Tony Harminc" >> Sent: Wednesday, 8 September 2010 9:20 AM >> >>> It's also how "classic" (base & displacement) addressing arithmetic, >>> which we all know deals only with unsigned values, can subtract. >> >> Classic base-displacement atithmetic is always addition, >> never subtraction. > >Ahem. > > LH R1,=H'-4096' > USING -4096,R1 > LA R2,* > LA R3,-4(,R2) > >What does R3 now address? > >This caused a great deal of debate on this list several years >ago. Very few contributors got it right. > >-- gil
This - http://www.kcats.org/csci/464/ho/usingtechnique.shtml - is taken from John Ehrman's note of long ago. Mike
