What is faster?

Comments

• Bobb Fwed Posts: 1,119

  2009-08-25 19:35 edited 2009-08-25 19:35

  you could put the two types into a program and check the CNT timer at the beginning and the end and figure out the difference between the two.
  
  My guess would also be that the CASE command is faster especially when a significant number of conditions are checked. I would also imagine CASE would use less memory than IFs.
  
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• jazzed Posts: 11,803

  2009-08-25 19:49 edited 2009-08-25 19:49

  Spin CASE is very clumsy. It is also limited to 64 cases ... you end up mixing IF and CASE then. If you want to see how it behaves, use BSTC or Homespun for listings and a debugger.
  
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• CounterRotatingProps Posts: 1,132

  2009-08-25 20:02 edited 2009-08-25 20:02

  jazzed said...
  Spin CASE is very clumsy. It is also limited to 64 cases ... you end up mixing IF and CASE then.

  OH now that's ugly ! ·· The case limit doesn't seem to be documented in the PropMan - did you stumble on that with the 65th case?·
  
  
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• Kye Posts: 2,200

  2009-08-25 20:05 edited 2009-08-25 20:05

  The case statement also waste a ton of memory. Really the difference is between a few longs when using ifs.
  
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• Bobb Fwed Posts: 1,119

  2009-08-25 20:18 edited 2009-08-25 20:18

  CASE is faster...here is the test code I used:
  
  

  PUB Main | value, start, time, tmp
  
    value := 10
  
    start := cnt
    IF (value == 0)
      tmp~~
    ELSEIF (value == 1)
      tmp~~
    ELSEIF (value == 2)
      tmp~~
    ELSEIF (value == 3)
      tmp~~
    ELSEIF (value == 4)
      tmp~~
    ELSEIF (value == 5)
      tmp~~
    ELSEIF (value == 6)
      tmp~~
    ELSEIF (value == 7)
      tmp~~
    ELSEIF (value == 8)
      tmp~~
    ELSEIF (value == 9)
      tmp~~
    ELSEIF (value == 10)
      tmp~~ 
    time := cnt
  
    DEBUG.dec(time - start - 368)  ' worst case: 8032 best case: 1200
    DEBUG.tx($0D)    
  
    start := cnt
    CASE value
      0: tmp~~
      1: tmp~~
      2: tmp~~
      3: tmp~~
      4: tmp~~
      5: tmp~~
      6: tmp~~
      7: tmp~~
      8: tmp~~
      9: tmp~~
      10: tmp~~
    time := cnt
  
    DEBUG.dec(time - start - 368)  ' worst case: 6224 best case: 1280
    DEBUG.tx($0D)
  
  

  
  
  
  IF/ELSEIF is worst case: 8032 cycles best case: 1200 cycles
  CASE is worst case: 6224 cycles best case: 1280 cycles
  And the difference is 8 longs in memory.
  
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  April, 2008: when I discovered the answers to all my micro-computational-botherations!