Showing posts with label poke. Show all posts
Showing posts with label poke. Show all posts

Saturday, December 27, 2008

COMPUTE! Magazine

Computer magazines used to be so much fun. First of all most of them had a very strong focus on programming and they would have articles about how to make electronic hardware to plug into your computer. Very much fun indeed.

Since I was the owner of a Commodore VIC-20 I would buy issues of COMPUTE's Gazette which catered specifically to Commodore 8-bit computers.

I remember one issue which included a machine code monitor listing. The program was in BASIC and it would POKE a machine code monitor (in machine code of course) into memory and then it would start up. I experimented with 6502 assembler using this monitor. I would write the assembly code down and then I would translate it myself to hexadecimal numbers and type them carefully in.

This was one of the great things about the computers of those days. A fifteen year old kid could figure this stuff out by reading magazine articles. There's probably no reason why it can't be made relevant to young people today. Why not make a cool and easy game programming tool for the Nintendo DS for example?

Thursday, June 7, 2007

Applesoft BASIC

So settling down to programming on the Apple II+, we had several books to help me with the process. Of course there was the standard green covered Applesoft book, and Mr. Alessi also has another book but I can't remember the title. I tried to find a shot of the book cover on Google but no luck.

Before we started writing inventory management software I tried my hand at creating some graphics. The Apple II had hi-res graphics (for that day), and Applesoft had high level commands for drawing so you didn't need to POKE and PEEK as much as in other BASICs. We had only a green phosphor monitor without color, but this was appropriate for business software development.

When editing a program in Applesoft BASIC, you could type some escape sequences to move the cursor around. If you moved the cursor up to the start of a line on the screen you could then reenter the line by moving the cursor to the right, and you could substitute some characters to change the line of code. This was crude compared to the way you did things on a VIC-20 where you just moved the cursor to the line you wanted to edit, changed just what was needed and hit Return.

Also, I had never written software before that used a floppy disk. This was another thing that I needed to become comfortable with. Our Apple II had 3 floppy drives, each was 143K. We also had a 16K card and a Z80 Softcard so the machine could run CP/M, but this was something we rarely did.