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 Robotics / RCX / 348
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Subject: 
Re: Speed of RCX interpreting bytecodes: slow
Newsgroups: 
lugnet.robotics.rcx
Date: 
Tue, 4 Jan 2000 23:24:17 GMT
Viewed: 
1302 times
  
Ben Jackson <ben@ben.com> wrote:
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...

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



Message has 2 Replies:
  Re: Speed of RCX interpreting bytecodes: slow
 
(...) From memory, the NQC was: int count; task main() { count = 0; CreateDatalog(100); ClearTimer(Timer(0)); while (count <= 1024) { if (count & 0xff == 0) AddToDatalog(Timer(0)); count += 1; } } The downloaded datalog will show the last log entry (...) (25 years ago, 5-Jan-00, to lugnet.robotics.rcx)
  Re: Speed of RCX interpreting bytecodes: slow
 
Its been a long time since I looked at the firmware in detail, but is it possible that the bytecode interpreter is driven from one of the timer chains? If this was the case, it wouldn't matter if the CPU could execute the bytecode in 200 cycles...it (...) (25 years ago, 5-Jan-00, to lugnet.robotics.rcx)

Message is in Reply To:
  Speed of RCX interpreting bytecodes: slow
 
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 (...) (25 years ago, 1-Jan-00, to lugnet.robotics.rcx)

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