Subject:
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Speed of RCX interpreting bytecodes: slow
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sat, 1 Jan 2000 21:09:50 GMT
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Viewed:
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1130 times
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While working on the barcode scanner I decided to see just how fast the RCX
could loop. A simple NQC program can do about 1000 counter loop iterations in
about 100 ticks, or 1 iteration/ms. This is shockingly slow. The native
H8/329 is clocked at 16Mhz and claims to do simple adds in 2 clocks...
This is causing me to seriously consider legOS for the first time...
--Ben
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Message has 4 Replies:
 | | RE: Speed of RCX interpreting bytecodes: slow
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| (...) Check out pbForth too! I will get around to doing some basic loop timing if you ask me nicely and tell me what kinds of test would be useful to do! pbForth is ready to run right out of the box, there is no compiler to mess with, and it's fun (...) (25 years ago, 1-Jan-00, to lugnet.robotics.rcx)
| | | RE: Speed of RCX interpreting bytecodes: slow
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| (...) OK, I did some basic timing experiments....for pbForth. : TEST1 10000 0 DO LOOP ; \ This is a hard loop of 10000 iterations : TEST2 10000 0 DO I DROP LOOP ; \ Same loop except the loop index is put on the \ stack and dropped - a no-op (...) (25 years ago, 1-Jan-00, to lugnet.robotics.rcx)
| | | Re: Speed of RCX interpreting bytecodes: slow
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| (...) Yes. It is important to realise, that the RCX, does not perhaps do the interpretation in the way you think. In each 'loop', it executes one instruction from each of the possible threads, and also reads the A-D's, on each sensor, and updates to (...) (25 years ago, 2-Jan-00, to lugnet.robotics.rcx)
| | | Re: Speed of RCX interpreting bytecodes: slow
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| (...) What is in a "counter loop iteration" ? Please share the NQC program you used to measure this with us. I fail to believe that a simple loop runs this slow. 16000 cycles per loop iteration does not sound right to me. -Kekoa (25 years ago, 4-Jan-00, to lugnet.robotics.rcx)
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