Sega

Revolutionary NFT Project ‘OASYX’ Teams Up with double jump.tokyo’s Web3 Tech Creative Studio 2xj [Tokyo, Japan] [March 17, 2023]: double jump.tokyo Inc. has announced that it is collaborating with SEGA’s popular 3D fighting titles, Virtua Fighter, Virtua Fighter 2, and Virtua Fighter 3, for its first NFT project, “OASYX.” The…

I’ll be the first person to admit, I’m a big Sonic fan. I got introduced to Sonic as a kid through the Sonic X tv show in the 2000’s. That show led me to play Sonic Advance on the Gameboy Advance (GBA). …

So I decided to code an SMS (Sega Master System) emulator from scratch, in javascript (applause). Why the SMS? Because it’s colorful (64 colours with linescroll tricks, graphics modes, a lot of tiles) Because of the ’80s TV spots with Walter Zenga Because of Sonic and Outrun Because… oh, come…

The Z80 seems more complex than the 6502, but not excessively complex. Less complex than a 8086, anyway (note: at the end, the source code was longer than my 8086 core, at least if we compare javascript with Rust). Anyway, it’s complex. My previous emulators (except the 8086 one, that…

After the deathly boredom of the Z80 instructions, in parallel I started building the VDP emulation code, just to have something onscreen as the construction of the CPU goes on. The VDP is controlled by the ports 0xbf (control port) and 0xbe (data port). Then, the data written to the…

Ok, I can consider myself pleased with the result. The emulator is far from perfect, but it runs Sonic and Outrun quite well, and this was our initial objective. Speed is also not bad on my old PC, and it could surely be improved. On the bad side, many games…

Ok so we wrote a bunch of instructions in our Z80 core, but in the good propositions for the new year, we said that we would have unit tested the CPU with at least one CPU exerciser. So I plugged in the Z80 cpu tests at jsmoo, and started testing…

So, at this point I have a more or less working debugger for the SMS. It’s time to implement the “emulator” part (with batch execution of cycles, input handling and many other things) to create a real application. At the moment, we are at 161 opcodes implemented and more or…

At this point, the hardest part begins. Writing each instruction of a Z80 core is not that hard; it’s mainly boring. Understanding why a program does not run, or crashes, or gets stuck is the real challenge. And, at the current state, I have a lot of roms that don’t…