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base:advanced_optimizing [2021-01-20 10:15]
bitbreaker [Forming terms]
base:advanced_optimizing [2021-03-05 16:57] (current)
bitbreaker [Forming terms]
Line 1430: Line 1430:
           sbc num           sbc num
           sta neg           sta neg
 +          
 +          ;num in a, carry set
 +          lda num
 +          sbc #$01
 +          eor #$ff
 </code> </code>
  
-There are of course also other expressions possible, just ponder a while about the term.+There are of course also other expressions possible, just ponder a while about the term. Also the carry flag after the negation can be influenced, depending on using sbc or adc for most cases ($00/$ff will cause an overflow).
  
 How's about forming terms with logical operations? We notice, that for e.g. (a + b) xor $ff is the same as (a xor $ff) - b: How's about forming terms with logical operations? We notice, that for e.g. (a + b) xor $ff is the same as (a xor $ff) - b:
base/advanced_optimizing.1611134149.txt.gz ยท Last modified: 2021-01-20 10:15 by bitbreaker