- I remember when I was a kid and Solaris was one of those games that I had bought with my own money. I proudly inserted it into my Atari 2600 I knew right away that this game was different from the rest. It had a plot, a goal and an ending; something that was a rarity for Atari games. I was immediately fascinated and after reading the instruction manual, something I always did, I was determined to finish the game. I spent hours on my living room floor happily drawing maps by hand on graph paper and trying to reach Solaris. I never did, but the strategic game play was so good that I actually enjoyed failing and didn’t get frustrated. Time passed. I never forgot this game and over the years I would keep coming back, each time more determined to finish it. Now, decades later, the internet has finally given me the tools I needed to complete this amazing game. I have made this guide so that others can do the same.
- The Group Decode ROM: The 8086 processor’s first step of instruction decoding (righto.com)
A key component of any processor is instruction decoding: analyzing a numeric opcode and figuring out what actions need to be taken. The Intel 8086 processor (1978) has a complex instruction set, making instruction decoding a challenge. The first step in decoding an 8086 instruction is something called the Group Decode ROM, which categorizes instructions into about 35 types that control how the instruction is decoded and executed. For instance, the Group Decode ROM determines if an instruction is executed in hardware or in microcode. It also indicates how the instruction is structured: if the instruction has a bit specifying a byte or word operation, if the instruction has a byte that specifies the addressing mode, and so forth.