ricardoquesada

Commando disassembled – fully commented code

In order to create Commando 2084, I had to disassemble Commando. My original intention was to patch what was only needed and stop there. But I got carried away and I ended up analyzing and commenting the entire Commando code. The commented code (that can be recompiled to generate the exact original binary) is here:Continue reading “Commando disassembled – fully commented code”

Commando 2084 – a game for the Commodore 64

Commando 2084 is the mix between Commando and Robotron 2084: it is like the original Commando game, but using the Robotron 2084 controls. You play it using the two joysticks at the same time: Joy #2 controls the hero direction Joy #1 controls the bullets direction But better if you play it with a UnijoysticleContinue reading “Commando 2084 – a game for the Commodore 64”

Unijoysticle 2: modern bluetooth gamepads for retro computers

Announcing Unijoysticle 2: Use modern Bluetooth controllers (gamepads, mice, smart TV remote controllers) in retro computers like the Commodore 64/128, Atari ST, Amiga and more. For further info go here: https://retro.moe/unijoysticle2

Atari ST: First impressions

A few months ago I got an Atari 1040 STF. I knew nothing about it when I got it, except that it was a similar to the Amiga. The Atari ST, the Amiga and the Macintosh were computers released in the mid 80’s, all of them based on the Motorola 68k, and all of themContinue reading “Atari ST: First impressions”

64K RAM Ought to be Enough: a demo for the PCjr

Updated 2018–10–08 A demo for the IBM PCjr by Pungas de Villa Martelli. It was presented at Flashparty 2018 and won the Demo category. Requirements An IBM PCjr with at least 64k RAM. Download Source code: https://gitlab.com/ricardoquesada/pcjr-flashparty–2018 Binary:pvm-64ko.zip (does not run on emulators) Technical description The demo is divided in the boot loader and demo 3Continue reading “64K RAM Ought to be Enough: a demo for the PCjr”

Cromemco System 3 computer

The Cromemco System Three is a Z-80 based computer. Which is nice, because I always wanted to learn Z-80 (this is my second Z-80 computer, the other one is a MSX2). But What I like about the Cromemco is how well-built it is. I love it. The computer is that not big, but it isContinue reading “Cromemco System 3 computer”

Performance of the 8088 on PC, PCjr and Tandy 1000

It’s well-known that you should measure the performance of your code, and not rely only on the opcode’s “cycle counts”. But how fast is an IBM PC 5150 compared to a PCjr ? or to a Tandy 1000? or how fast is the Tandy 1000 HX in fast mode (7.16Mhz) compared to the slow modeContinue reading “Performance of the 8088 on PC, PCjr and Tandy 1000”

IBM PCjr: Zero-day Data-destroy vulnerability

IBM PCjr zero-day data-destroy vulnerability (AKA: Joykill). Description: This vulnerability allows local and remote attackers to destroy the contents of the floppy diskette. User interaction is required to exploit this vulnerability. The issue results from the lack of proper validation when starting the manufacturing system test. Exploit (local):

IBM PCjr BIOS dump

The IBM PCjr BIOS is very well documented in the IBM PCjr Technical Reference manual (a must read for every PCjr developer). The only problem is that navigating that code is not easy. It has all the problems from scanned books: the fonts don’t look good no hyper-links and difficult to search So I dumped theContinue reading “IBM PCjr BIOS dump”

Tandy 64 Jr. – an intro for the IBM PCjr

Happy new year! We (PVM) ported our Tandy 64 intro (originally designed for the Tandy 1000HX) to the IBM PCjr. Requirements: IBM PCjr. with 256k RAM Download: Binary: tandy64jr.zip Source code: https://github.com/c64scene-ar/tandy64/tree/ibm_pcjr Worth mentioning: Runs flicker-free Stable raster-bar, without garbage (world-first?)