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???
12/16/03 16:12
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#60745 - RE: if then construction in assembly
Responding to: ???'s previous message
hi,
Why isnt there a CJE instruction or im i just missing the point?
Both yes and no.

Okay, let imagine that CJE is presented, and what we will have then...
CJNE requires 3 bytes of code. So, CJE might take the same size. Let say, you have all the 256 CJE comparisons in-line and so it eats 768 bytes of the program memory. Now try to answer: how may it be possible to do short jump (CJE uses relative +/-128 dimension) from middle of those CJE,CJE,CJE etc? :)
Opposite it, CJNE gives you a chance to do LONG jump or CALL near comparison command if you have found appropriate condition.

Btw, here you may use another way, if need:
; R0 contains examined value
MOV A,#1
XRL A,R0
JZ  ROUTINE_1
MOV A,#2
XRL A,R0
JZ  ROUTINE_2
etc
And even more: if you look at code I typed above more careful than you may find even shoten way than I shown (=

cu





List of 10 messages in thread
TopicAuthorDate
if then construction in assembly            01/01/70 00:00      
   RE: if then construction in assembly            01/01/70 00:00      
      RE: if then construction in assembly            01/01/70 00:00      
   RE: if then construction in assembly            01/01/70 00:00      
   RE: if then construction in assembly            01/01/70 00:00      
      Jump table            01/01/70 00:00      
         RE: Jump table            01/01/70 00:00      
   RE: if then construction in assembly            01/01/70 00:00      
      RE: if then construction in assembly            01/01/70 00:00      
   don\'t forget the carry            01/01/70 00:00      

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