[stella] 6502 questions

Subject: [stella] 6502 questions
From: Ben Larson <wazzapfool@xxxxxxxxx>
Date: Thu, 11 Oct 2001 08:24:45 -0700 (PDT)
OK I am seriously confused as to the how the compare
and branch instructions work.  Ok first of all,
correct me if I am wrong, but when you do a BPL
doesn't that check to see if the value you are
comparing is greater than the the value in the
accumulator?  Well if that's so, then is the processor
comparing the two numbers as unsigned 8-bit integers
or signed?  In other words, what would be the outcome
of, say...this:

   LDA #100
   CMP #-20        ; -20 signed = 236 unsigned
   BPL AIsLess     ; in a 2's comp. representation


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