[Coco] memorising opcodes was:Re: DECB or ECB Compiler

Frank Pittel fwp at deepthought.com
Sun Oct 3 18:37:53 EDT 2010

On Mon, Oct 04, 2010 at 07:49:00AM +1000, Bob Devries wrote:
> Hi John,
> You said:
> >Bill Daniels, who I seem to remember hand-coded without an
> >assembler and had
> >the entire 6809  instruction set memorized (not just the
> > mnemonics..)... but I could be wrong there...)
> Actually, when you've had to hand code machine code, it's not too
> hard to memorise the opcodes (the hex codes). In the last week or
> so, I was put in the position of having to dis-assemble some 6800
> code, and I successfully did that for over two pages of code. I
> haven't used 6800 code since the *very* early 80's.
> The computer I hand coded for was the DREAM 6800.

That reminds me of the microprocessor classes I took! The "trainer" was
based on an 8085. We entered our programs in hex on a hex keypad. There was
no assembler so we would write the programs in assembly and then hand assemble
the program using an op-code table. After a while you learned the op-codes for the
most of the instructions. Occasionally for some of the more obscure instructions you
would have to look them up, but that was rare.

the other Frank

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