Jay's Commodore Podcast
16 episodes -
last episode 09 May 2018Join Jay Versluis for tips and tricks on programming in BASIC and Assembly on vintage Commodore systems.
2018-05-09
I’ve recently discovered a tweet that showed a Commodore 64C complete with green monitor and 1541-II drive, heavily dust covered, but still working and being used in a Polish Auto Shop. The picture itself was fascinating enough, but I’ve also discovered that it was a screen grab from a video – which I’m including here ... Read more
2018-05-08
In this screencast I’ll show you how to write your own INPUT routine in Commodore BASIC. This comes in handy when you want to reject certain keys from being used when asking users for keyboard input. In my example I’m going to allow all alpha characters (A-Z), as well as SPACE, RETURN and the DELETE ... Read more
2018-04-18
In this episode I’ll show you how to create the iconic flashing borders on Commodore machines. Back in the day, when the system was loading, this was a nice way to indicate that the computer is busy doing something rather than being dead. I’ll show you the principle both in BASIC and in Machine Language ... Read more
2018-04-17
In this episode I’ll demonstrate how to use programmatic loops in Commodore BASIC. I’ll show you how to use the FOR/NEXT loop (available in all versions of Commodore BASIC), as well as the DO/WHILE loops (available on the Plus/4 and C128). Enjoy!
2018-04-16
In this episode I’ll explain the concept of Flow Control in Commodore BASIC. It’s kind of a video update of a post I did a while ago. In essence, it means that we can tell the programme to take a different route in the code depending on a condition that’s met. We’ll explore the IF/THEN ... Read more
2018-04-16
Did you know you can run Commodore BASIC v2 on your Mac and Linux systems as a scripting language? It’s true – thanks to the marvellous efforts of Michael Steil and James Abbatiello. They’ve adapted the original BASIC v2 as featured on the VIC-20 and C64 with additional routines so that it works natively on ... Read more
2018-04-13
The Commodore 128 has a built-in machine language monitor which makes it ideal for ML development. However, most (or pretty much all) documentation on this subject is geared towards the Commodore 64, making it slightly difficult to get a head start in writing ML code for the 128. Before I forget how to do it, ... Read more
2018-04-11
In this episode I’m adding statistics support to my previous lottery generator on the Commodore 64. I’ll add an array that is updated if my supplied numbers have been matched, and how many times over how many draws this has happened. I’ll also add an option to pause the programme and display the statistics before ... Read more
2018-04-10
In this episode I’m amending my previous lottery number generator to take six lucky numbers from the user to match against the randomly drawn numbers from the Commodore 64. This will allow us to compare what the computer has drawn to the user’s input, as well as keep drawing numbers until the user input comes ... Read more
2018-04-09
In this episode I’ll show you three ways to take user input from the keyboard in Commodore BASIC. The INPUT and GET commands work on all systems, while the GETKEY command only works on the Plus/4 and C128. I’ll demonstrate how to use all of them. This will come in handy for our little lottery ... Read more
2018-04-02
In this episode I’m demonstrating how to print numbers in evenly spaced columns in Commodore BASIC. On the C128 and the Plus/4 we can use a nifty little function called PRINT USING for this, with which we can format the output of any printed text or variable. On the C64 and VIC-20 that function doesn’t ... Read more
2018-04-01
In this episode I’ll demonstrate how to sort a numeric array on the Commodore 64. The same principle works for string arrays, and of course on all other Commodore BASIC computers. The technique I’m using here is called Bubble Sort: in effect we’re comparing the first two items in the array, and if the left ... Read more
2018-03-31
In this episode I’ll demonstrate how to draw random lottery numbers on a Commodore 64. The secret sauce here is not only the RND function to generate random numbers, but also two loops inside each other that prevent the same number from coming up more than once. Here’s the lottery generator code: 10 x=rnd(-ti) 20 ... Read more
2018-03-29
In this episode I’m demonstrating how to build a word splitter on the Commodore 64. We’ll use string functions to parse a sentence and split each word off into an array of words so that they can be analysed later (for example, as part of an adventure game). Here’s the code I’m building: 20 input ... Read more
2018-03-28
In this video I’ll demonstrate how to build a simple clock on the C64. We’ll go through this process step by step, including the built-in TI and TI$ variables, string formatting with LEFT$, RIGHT$ and MID$, as well as screen formatting. Here’s the code I’m writing – works in Commodore BASIC v2 and above: 5 ... Read more
2018-03-27
In this episode I’ll demonstrate how to create those seemingly random YouTube Video IDs using a Commodore 64. Here’s the code I’m writing – works in BASIC v2 and above: 10 print chr$(14) 20 gosub 100:x=rnd(-ti):cn=1 30 a$="https://youtu.be/" 40 for i=1 to 11 50 rn=int(rnd(0)*62)+1 60 a$=a$+yt$(rn) 70 next 80 print:print cn;" : ";a$ 85 ... Read more