27 Jun
2001
27 Jun
'01
4:59 a.m.
On Wed, 27 Jun 2001, Ethan Dicks wrote:
Seriously, though, I did get my start on the 6502 by
typing hex into
the TIM monitor in the new PETs (old PETs had a tape-loadable
monitor). I was overjoyed when one of the members of the local
computer club sold me a 2532 with a 4K monitor program that did
line-at-a-time assembly. I didn't mind page after page of LDAs and
STYs, but it was a real boost to my productivity to not have to
calculate branch offsets manually.
I first started to learn assembly language when I noticed that the
mnemonics in the assembly listings in the Apple II Reference Manual had
hex codes next to them, which corresponded with what you'd see when you
listed code in the Apple ][ monitor. I then had the brilliant idea to
poke a byte into a location in the monitor and then list it to see if the
hex code produced the associated mnemonic, and sure enough it did! I was
flabbergasted. Of course this was a completely silly discovery, but for
someone hacking on their lonesome and having to rely on themself to figure
things out, it was a big breakthrough.
I got really good at programming in hex code, and never moved on to
assemblers. I tried a few, and had many of the ones popular during the
day (EDASM, LISA, Orca/M, Big Mac, etc.) but never liked any of them. I
preferred the immediacy of the monitor and hex codes. I got to the point
where I rarely had to reference the manual. I knew all the opcodes for
all the instructions in all their various addressing modes, etc. I even
got good at calculating offsets for relative jumps in my head (like an
idiot savant).
To this day I can still pound out 6502 code in hex. It's so ingrained in
my skull that it's scary.
Sellam Ismail Vintage Computer Festival
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