The Fetch-Execute Cycle
January 23, 2010
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No, not some witty, metaphorical lead into a great pedagogical insight today, this post is actually about the Fetch-Execute cycle. Or at least the 4th paragraph on is. This, and the next 2 paragraphs are a little less geeky…
I’m enjoying (nay, loving) teaching AS Computing, having had no intake for the course last year. At the moment we have 3 students (down form the 5 we had in September) and with the new AQA course I’m covering topics I’ve not looked at since my bachelors, back in 2000-3.
Even better news, having just surveyed our Y9 students as part of their Options procedures it seems that around 30 (of a cohort of 235) are interested in the new GCSE Computing which OCR are piloting from September. Of course the figures may well drop once they realise it will probably have to run after school, but it’s a very positive start – and if only a dozen take it then we’re likely to have a much more healthy uptake in Computing in the future.
So anyway, back to the geekiness. Having joined the Computing At Schools Google Group some time ago, I posted there that I was looking to get back into Assembly (last tackled 9 years ago – eek!) and someone posted a link to a KS3/4 friendly Little Man Computer simulator, and a slightly more powerful browser based Little Man Computer simulator.
Both allow you to use machine code write small programs for a notional hardware platform and to test the finished program. The first is great for introducing the concept of the stored program concept and the fetch-execute cycle, whereas the second is great for actually creating something, and you can also write the commands in a form of Assembly and you can see the assembler actually convert the mnemonics into opcodes.
So yes, I spent a large part of my Saturday evening writing a tiny program that will multiply two numbers (using loops and conditional statements to count down the iterations of adding the first term to itself repeatedly). I’d forgotten just how much I love being a computer nerd some days