Ok, here's mine - for a real micro :)

http://www.worldofspectrum.org/stk/
http://www.worldofspectrum.org/infoseekid.cgi?id=0012128

Can't remember significant POKE'ing trivia, but can still write Z80
Assembly to save my life, after almost 20 years... will probably not
remember only rarely-used instructions, including most undocumented
ones (Z80 had a ton of these). In the good times I'd write simple
routines in straight hexadecimal.  It's amazing how well your memory
works when you don't have an IDE with auto-completion - or at least I
(we?) like to think that, because the alternative conclusion is that
my brain was better as a teen :)

Now in the "it's never too late to learn" category, just a few months
ago I found some retro page explaining the fastest possible method for
copying blocks of memory with the Z80 - a critical operation for games
using double-buffering. I already knew that looping instructions like
LDIR/LDDR were slow and used simple unrolling; but there's an even
faster method, using the stack pointer to alternatively index the
source and destination blocks, loading as much data as possible into
all other registers (including the alternate ones) with POP
instructions, then writing with PUSH's, loop till end... this flies
because the 16-bit PUSH/POP instructions are 2X faster than equivalent
16-bit LD's (probably true for other 8-bit CPUs too), plus you get the
src/dest address incs/decs for free. Only trick is disabling
interrupts because we are messing with SP. And of course, since PUSH
and POP update SP in inverse directions, your back-buffer must be all
upside-down so the block-copy routine doesn't need extra logic to
compensate for that.

(Now let me return to my day job, i.e. >10-Mb footprint for HelloWorld
in any modern lang)

On Oct 19, 10:57 am, Christian Catchpole <[email protected]>
wrote:
> screen colour = black
> border colour = black
> cursor colour = white
>
> (and i remembered that from 1987)
>
> http://twitpic.com/2yzlcp

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