A Map of the TMS-9900 Instruction Space


March 1979


Back in the very early days of hobby computing, when all programming had to be done by hand, and I mean really by hand, flipping the switches for each BIT of the program, one useful piece of information was a chart showing how the instructions were organized into families. This allowed the programmer to memorize the hundreds of bit patterns that made up the instructions. When I offered BYTE the charts for the wonderful Z-80, they turned me down, but they did ask for the 9900 and the 1802, which I was happy to supply.