Mini-challenge - finding fine threads from the archives

[BigEd]

Here's an idea, inspired as a mutation of an idea of Dr Jefyll's: what old threads would you like to share, here on 6502.org?

Only two rules:
- Can't have a thread you created yourself
- Can't have a thread started this year, or a sticky thread

Also, please present your finds as linkified thread titles like so:

• Timing Diagrams. Visualizing 65xx Timing. (2014, Dr Jefyll)
  Detailed 6502 block diagram (2006, BitWise)
  Extra cycle in crossing page boundary question (2015, Bryan Parkoff)
  A program for today (2011, dclxvi)

If you comment here, you have to include at least one fine old thread link!

[BigEd]

Here's another one:

• 6502-Core Comparisons: Fitting a Xilinx Spartan 2 XC2S200 (2010, ElEctric_EyE)

(Things were quite lively for a while in the world of 6502 cores and FPGAs, but seem to have gone a bit quiet.)

Any more fine threads from anyone?

[RichTW]

Here's a few I enjoyed:

• Visualizing the 6502 (2010, BigEd)
  A taken branch delays interrupt handling by one instruction (2010, HiassofT)
  NMOS 6502 Reset bug (2011, Dr Jefyll)
  binary to ascii (2013, wwl)

[BigEd]

Nice choices Rich - thanks!

Here's my obligatory additional submission:

• Working SBC-3 (2008, 8BIT)

[GaBuZoMeu]

There are much more but to throw them in:

• BRK detection (2002, schidester)
  String Comparison for PASCAL style Strings (2005, Wheels)
  Fast CRC without tables (2004, debounce)

[BigEd]

Nice finds, GaBuZoMeu, thanks for stepping up to the challenge!

Obligatory threads... here's a couple recently mentioned by Garth and Jeff, respectively:

• Survey: A 65C02-based PC (2003, 8BIT)
  TTL 6502 Here I come (2015, Drass)

[BigDumbDinosaur]

GaBuZoMeu wrote:

• BRK detection (2002, schidester)

schidester wrote:

My findings show that BRK is absolutely, completely useless except in the one special case where the ONLY cause for interrupt can be from it (i.e., no interrupt driven I/O). I'll explain shortly...I'd love to be proved wrong on this or shown a way to do it, but my suggestion to anyone wishing to benefit from my experience is to stay the heck away from BRK!!!

I always get a laugh when someone declares a particular 6502 feature to be useless, as I've found a number of uses for BRK, as well as its close cousin in the 65C816: COP.

Apparently, Mr. Schidester has not engaged in the debugging of a program that was executed with the G ("go") command of a typical 65xx machine language monitor. If he had, he would have found BRK to be a convenient means of temporarily halting program execution to examine the registers, dump memory, etc. In fact, I have a macro called (what else) BREAK that I use to put break points into programs in areas where I suspect I might run into bugs.

Declaring a 6502 feature useless reminds me of the periodic debates on the value of the 6502's decimal mode (I use it for binary-decimal conversion) or (<zp>,X) addressing (my 28L92 driver makes extensive use of that addressing mode to select which channel is being processed).

[BigEd]

Thanks for taking part BDD - but where's your mini-challenge entry? You seem to have mistakenly taken exception to some small part of an interesting old thread here.

Oops, almost forgot the obligatory fine thread from the archives:

• the fast realization of π-spigot algorithm (2016, litwr)

[BigDumbDinosaur]

BigEd wrote:

Thanks for taking part BDD - but where's your mini-challenge entry? You seem to have mistakenly taken exception to some small part of an interesting old thread here.

Oops, almost forgot the obligatory fine thread from the archives:

• the fast realization of π-spigot algorithm (2016, litwr)

How about some back-and-forth about assembler syntax (Mats, Jan 2004)?

[BigEd]

Thanks BDD!

Obligatory:

• Mini version of the OSI-300 trainer (2015, ChuckT)

[BigEd]

Any more responses to the mini-challenge? Here are two more threads for your retroreading pleasure:

• 65816 direct threaded NEXT (2005, dclxvi)
  4MB SRAM Module (2011, 8BIT)

[GaBuZoMeu]

This one is exceptional I think:

1. Getting young people into 6502

[BigEd]

Good find GaBuZoMeu! I enjoyed reading that 2013 thread.

Obligatory thread... let's see... how about

• Did commodore attempt development of an upscale 6502 (2013, carmel_andrews)
  Static recompilation of 6502 machine code from NES ROMs (2013, fachat)

[MichaelM]

UM* (multiplication) bug in common 6502 Forths. Includes good animation of several multiplication algorithms by Dr Jefyll.

[GaBuZoMeu]

A fine one that presumably never will finish:

• viewtopic.php?f=8&t=1603 (BigEd, 2010)