[HN Gopher] Easy 6502
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Easy 6502
Author : rahimnathwani
Score : 97 points
Date : 2022-05-29 11:39 UTC (1 days ago)
(HTM) web link (skilldrick.github.io)
(TXT) w3m dump (skilldrick.github.io)
| Night_Thastus wrote:
| For anyone interested in the 6502, assembly and just in general
| how things like loops, conditional branches, hardware
| communication, etc all work, I HIGHLY recommend Ben Eater's
| videos on the subject:
| https://www.youtube.com/watch?v=LnzuMJLZRdU
|
| They are incredibly fascinating!
| [deleted]
| [deleted]
| rahimnathwani wrote:
| I came across this when I was searching for resources to help
| better understand ALUs and assembler.
|
| I love it because:
|
| 1. My first computer (an Acorn Electron) had a 6502 processor,
| and gave me my first exposure to assembler.
|
| 2. It's been built so you can do all the exercises in the
| browser. I really like stuff like this (e.g. Scrimba), as it
| makes it so much more likely that you'll get started.
|
| A related point: as I go through it, I'm thinking about which
| instructions are really necessary (maybe all of them?) and why it
| would be inconvenient if you didn't have a particular
| instruction.
| pvg wrote:
| _which instructions are really necessary (maybe all of them?)
| and why it would be inconvenient if you didn 't have a
| particular instruction_
|
| The ones added in the 65C02 offer some insight there, a very
| brief overview from the Wikipedia page:
|
| https://en.wikipedia.org/wiki/WDC_65C02#New_and_modified_ins...
|
| Somewhat related and mentioned in one of the comments
| downthread, you can view Woz's SWEET16 as a 'the 16 bit CPU a
| 6502 system designer and programmer wished they had' take.
| jacquesm wrote:
| The simplest computer has only one instruction:
|
| https://en.wikipedia.org/wiki/One-instruction_set_computer
|
| There is even ZISC:
|
| https://en.wikipedia.org/wiki/No_instruction_set_computing
|
| Check out brainfuck if you are into stuff like this.
| rahimnathwani wrote:
| Haha these are really interesting.
|
| It seems to program with such a reduced instruction set
| requires one to be either a genius or a computer (i.e.
| generated code). I'm neither :(
| jacquesm wrote:
| Either that, or a compiler with such an instruction set as
| the target.
|
| For instance:
|
| https://github.com/arthaud/c2bf
|
| It seems like this is a frivolous subject, but it is
| actually quite enlightening to realize just how little is
| required to get something that computes, it changes how you
| view the whole concept of computation.
| codedokode wrote:
| Very interesting, never heard of this. I love Hacker News for
| being able to learn something new from comments. Although I
| cannot agree with labeling "horizontally nanocoded CPU" as
| "No instruction set". There are instructions, they are just
| low-level.
|
| I wonder, can Turing machine count as "Zero Insturction Set"?
| Technically there is no sequence of instructions.
| actually_a_dog wrote:
| I like this. I learned ASM first on the PDP-11, and I thought
| that was a _great_ introduction to assembly language concepts.
| 6502 has a lot of similarities with the PDP-11 instruction set,
| but also gives you the ability to (if you want to) more easily
| deploy your code to a real chip inside a real machine.
| sircastor wrote:
| I used this when I was learning 6502 assembly so I could build my
| senior project (An NES game). It was tremendously helpful to
| rapidly test ideas on how to manipulate bits and test
| subroutines.
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(page generated 2022-05-30 23:00 UTC)