Decoding the NEC V20 Microcode

Warning: This page contains hundreds of emoji. If you're using a screen reader, be sure it doesn't read them all out loud. A whole bunch of emoji. What could they mean? This particular post comes out of left field a bit. I was playing around with a web application I had made - an online disassembler for the x86  - when I noticed that emoji were being encoded into the url.  I pasted a goat emoji,  🐐   and I noticed the encoding  %F0%9F%90%90 . Now, if you're familiar with x86 assembly language at all, hexadecimal 90h is probably familiar to you. It's the opcode for a null operation or NOP . I had a brief nerd chuckle over the thought that goats were the NOP s of emoji, but then I got curious. F0h on the 8088 is the LOCK prefix. This prefix is generally used to coordinate exclusive bus access with a coprocessor such as the 8087, but otherwise does nothing for most instructions on the 8088 and is ignored (this would change on later Intel CPUs). That leaves...

GlyphBlaster The GlyphBlaster in action - is that a cat in text mode??  There's a certain genre of retro-hardware hack that everyone recognizes is technically cheating, but has a certain audaciousness to it that merits respect regardless. I hope that this one falls into that category! A few years ago, I was impressed by TheRasteri's PiPU project - basically, a Raspberry Pi-powered mapper for the NES. Of course, it can play DOOM: The Raspberry Pi Pico and its RP2040 microcontroller have reinvigorated the retro-computing hobby quite a bit, enabling such devices as the PicoGUS , PicoMEM , PicoIDE , and most recently, the OneROM .  It was the latter device that got me thinking. I recently used a OneROM to replace the font ROM on my CGA card, and subsequently I was able to replace IBM's classic 8x8 font with a custom one. Here's Frogblock by Polyducks: The "Frogblock" font loaded onto a OneROM replacing the CGA's font ROM The programmability of the OneROM intr...

This is Part 4 of a series on PC floppy copy protection methods. You can read the previous parts here:   Part 1, covering Formaster Copy-Lock Part 2, covering Softguard Superlok Part 3, covering EA Interlock Vault Corporation Vault was conceived in 1979 and incorporated in 1983. There's not much information about the early days of the company, but 1983 was a busy year for them. The trademark filing for Prolok, their first copy-protection product has a first-use date of March 1983. That same year would see several full-page, color advertisements in various PC magazines, making them one of the major competitors of firms like Softguard . Compared to the modest back-page adverts from other copy-protection firms, Vault's advertisements were very slick - clearly put together by a professional ad agency. One of Vault's biggest customers was  Ashton-Tate , makers of the industry-leading  dBase  database software and later owners of the  Framework  office...