[Coco] memorising opcodes was:Re: DECB or ECB Compiler
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
More information about the Coco