Commodore Adding very large integers in 8 Bit BASIC As we've discussed, large integer math is a pretty interesting problem, even for modern computers. What if we wanted to add very, very, very large integers without using scientific notation, but this time let's do it extra slowly. Extra slow... this seems like a job for BASIC!! Strings We're going

code MOS paper tape format I built the world's worst paper tape reader some weeks ago. It works pretty okay on anything with a USR-style port like a KIM-1 clone or a VIC-20. 0:00/1× Paper tape was (and is) an interesting medium. Sure it's hard to work with and fragile, but it also

C64 A little more speed from the 6502 Can we get a little more speed from a 6502 than we did last week? Almost certainly. The memory test we used was a general-purpose one. It's flexible and reusable. The price is some speed. Let's try and make it faster. The test machine for this one I'm going to

C64 Featured How fast can a 6502 transfer memory The amazing Gregorio Naçu posted the article title graphic this week to bring attention to the venerable 6502 processor and poke fun at Apple's M2 chip marketing slides. He's doing probably the most ambitious single-person Commodore 64 project I know of and has a fantastic blog. Apple claims the new

code Almost primes with TinyBASIC on the KIM-1 clone: PAL-1 Bill Gates has been a controversial figure in the Computer World for 50 years now. Back in 1976, he famously (infamously?) wrote a letter bemoaning what he saw as rampant piracy of BASIC. Micro Soft was selling their version of BASIC, which is quite good for a whopping $150. This

code VIC’s Revenge, the drop-in replacement for the VIC-20 VIC chip Part 1: Introduction, design goals, and FAQs I'm doing a year-long project to reverse engineer the output and functionality of a VIC-20's video chip, and create a drop-in replacement. At the start of this project (a few days ago), I only actually know how to do a percentage of the things I'll need to complete this project.

C64 64 Bit Addition and Products on Commodore: The Wheat and Chessboard problem Dealing with large numbers in computing has been an attractive problem area for a long time. Using an average calculator might lead you to believe that it's too tricky for most applications. 0:00/1×But it's not that difficult. And to prove it, we're going to implement this calculation

Commodore Vicky-20 S Video Mod Results I'm very pleased with my PAL VIC-20 replica, the Vicky-20 [https://www.tindie.com/products/bobsbits/vicky-twenty-commodore-vic-20-pcb-replica/] . It's almost a year old and the VIC-20 that sits on my desk all the time. I've wanted the absolute best video out of this thing I could muster. This board is fortunately

C64 Yet another version of the 100 door problem; this time, let's extend Commodore BASIC to add PRINT @, shall we? I stumbled across a ZX Spectrum version [https://www.rosettacode.org/wiki/100_doors#ZX_Spectrum_Basic] of the 100 Door problem that got me thinking. Wouldn't it be nice to have PRINT AT in Commodore BASIC? We do this in Assembly all the time. We already know from several

calculator Simple exponents on an HP-16c I've been on the prowl for an HP-16c for quite some time to add to my rather large calculator collection. My daily driver for the last 25 years is an HP-32SII. Simple, rugged, reliable, and does everything I need it to do. I stumbled on a kit that runs an

code Fibonacci 1-10 on the KIM-1 (and clones) Sometimes there's an absolute joy in doing something the hard way to REALLY understand what's happening. I struggled (still struggle) with wrapping my mind around using the display on the KIM-1. The best way (for me anyway) to be motivated to learn something is to have an outcome in mind

C64 The terrible random number generation in the Commodore 64 (and 128) Quite a while ago, I started playing with random numbers on 8 Bit machines. I don't think anyone is doing "serious" work on these machines, but playing with Ciphers and Crypto got me at least curious about how a Commodore 64 generates random numbers. There are many ways to determine

Commodore Getting green and amber screens from a MiniPET 40/80 In mid-2021, I built a MiniPET 40/80. It's one of the best replica kits I've ever seen. Even the keyboard is wonderfully awkward to use, just like a real Chicklet PET keyboard is. Switching between ROM versions with DIP switches has been great for learning and experimenting with internals.

C64 Simple splitting the screen with two colors on the Commodore 64 Someone asked me yesterday how to very simply split the Commodore 64 screen to display two solid colors. The screen is 1000 "blocks"(character cells) starting at Hex $0400 (1024 decimal). It's 40 characters wide and 25 rows. 25 rows don't divide evenly, so we can tell the VIC register

code A visual 100 Door Problem solution in Python Last year, we did the 100 door problem on many platforms in BASIC and Assembly language [https://imapenguin.com/just-for-fun-the-100-door-problem-on-several-different-systems/] . The 100 door problem is: * There are 100 closed doors in a row. * You walk past the doors 100 times (100 passes) * The first time, visit every door. If the

C64 Permutations of 1 to 9 in Python, BASIC, and 6502 Assembly Someone asked me this week if I would help him with a graph theory problem on 8-Bit machines. The first task was to get all permutations of 1 to 9. Since the total permutations is 9! (362,880) I knew this would take a while. Learning without learning, the standard

Making and breaking codes Part 14- VIC Cipher on the Commodore VIC-20 I love pretty good encryption that requires nothing but a pencil and paper [https://imapenguin.com/simple-unbreakable-encryption-with-a-pencil/], or a deck of cards [https://imapenguin.com/pontifex-from-cryptonomicon/]. VICTOR In the twentieth century, Soviet spies used a simple paper cipher based on the codename VICTOR of a Soviet agent spying in the

C64 Can you do Advent of Code on 8-Bit Machines? There's a wonderful yearly online event called Advent Of Code [https://adventofcode.com/2021/] (#adventofcode). Each day there are two code challenges that follow a holiday narrative. Some of them are easy, and some of them are quite difficult. This year I've attempted to do as much of it as

C64 Quick Tower of Hanoi with Sound on the Commodore 64 I LOVED Ayliean MacDonald's [https://linktr.ee/Ayliean] Tower of Hanoi video [https://www.youtube.com/watch?v=PGuRmqpr6Oo] on Numberphile [https://www.youtube.com/user/numberphile] this week. I wanted to try it with some "soothing" sounds from the 80s with the SID from a Commodore 64 No code

C64 Dice frequency I've been obsessed with the Random number generator on the Commodore computers for a LONG time, and I'm not the only one who is [https://www.youtube.com/watch?v=CfutqhHnVX0], to be sure. We've used this random function in many of the Cipher series articles before, both via BASIC

Atari A week of diving a little deeper into my Atari 800XL I'm a Commodore guy through and through. This isn't tribalism, it's what was in my room from 1983 to when I graduated High School in 1993. After my sorta failed attempt at spending the month of September with my Coco 2 [https://imapenguin.com/two-weeks-with-mostly-a-coco-2-in-september/], I decided for October to

Coco Two weeks with a Coco 2 in September In the inside baseball realm of vintage computer enthusiasts, a few hashtags have emerged to support one's favorite retro computers. The main one in September is #SepTandy While I've had this Tandy Color Computer 2 for many years, I've almost never used it. Out of all of my vintage systems,

Coco Slot Game On Tandy TRS-80 Pocket Computer PC-4 One of my first ever real programs was a blackjack game I made in BASIC on a Sharp 9300 calculator to impress my Adv. Algebra teacher. I have seen the handwritten copy of this somewhere around here recently, but I'll be darned if I can't find it now. Slot Game

C64 Calculating Pi via the Gregory-Leibniz series in BASIC on the Tandy Color Computer 2 Back in March, we did a simple set of programs to brute force calculate Pi using a simple and well-known series [https://imapenguin.com/estimating-pi-with-the/]. It works, even if it's inefficient. Speaking of inefficient, it's September and that means it's time for #Septandy! I have a Tandy Color Computer 2

C64 Just for fun, the 100 door problem on several different systems What's the 100 door problem? It's a just for fun problem in "beginning" math and computer courses. The idea is simple: There are 100 closed doors in a row. You walk past the doors 100 times (100 passes) The first time, visit every door. If the door is closed, open