Re: [stella] Light gun/pen

Subject: Re: [stella] Light gun/pen
From: Nick S Bensema <nickb@xxxxxxxxxxxx>
Date: Tue, 30 Sep 1997 12:36:44 -0700 (MST)
>ObProgramming:  How long do you think it would take someone who has
>only had one 8086 assembly language course about five years ago to
>catch on to the 6507?

I guess it depends, how well did you do in the 8086 class?

Looks like you've got a head-start, knowing about dealing with individual
bits and bytes.  You just need to find a good reference, though a tutorial
would probably be better.  Whenever I try to learn from scratch with a
reference, I can't pace myself, and always try to read too much and never 
absorb anything.

But considering there aren't many opcodes or addressing modes, I'd say
you could learn the whole thing in a month.  Though it'll take you a
while to learn the techniques and nuances, like the overflow bit and
exactly what gets pushed to the stack when you JSR.

Here's a six-line head-start on the mnemonics, though....enough to give
you a teeny bit of literacy when reading source code.  Remember in branching
instructions and stuff, that the P register keeps certain details about the
last mathemetical or read operation.

Operands: #$constant $address $address-plus-x,x ($pointer)
LDx  Load register x               ADC: A+=  Cycle in carry:  Branch if:
STx  Store contents of register x. SBC: A-=   YES     NO  result=0 BEQ !=0 BNE
PH?, PL?  == push, pop A or P      DEY: Y--   ROR >> LSR  result>0 BPL  <  BMI
T??  Transfer registers, AX etc  AND, ORA, XOR: Boolean   SEC C=0   CLC  C=1

Meaningless enough for you?  I don't know why I just typed it...
but I guess I can't do all that hard work without sending it to the list.

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