The Alto hardware manual explains how the microcode works (see sections 2 and 9 and try to memorize Figure 1). For examples, see the existing Alto microcode. Th

The Alto hardware manual explains how the microcode works (see sections 2 and 9 and try to memorize Figure 1). For examples, see the existing Alto microcode. The subsystem manual p90 describes the MU microcode assembler and the syntax. See also RPRAM in the subsystem manual that describes how to load microcode into control RAM. I haven't seen anything like a howto/tutorial for microcode in the Alto documentation. http://bitsavers.informatik.uni-stuttgart.de/pdf/xerox/alto/AltoHWRef.part1.pdf http://bitsavers.informatik.uni-stuttgart.de/pdf/xerox/alto/... http://bitsavers.informatik.uni-stuttgart.de/pdf/xerox/alto/microcode/ http://bitsavers.informatik.uni-stuttgart.de/pdf/xerox/alto/... http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/xerox/alto/memos_1978/Alto_Subsystems_Apr78.pdf http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/xer... If you want to try this stuff out for yourself (and don't have an Alto handy), use the ContrAlto emulator: https://github.com/livingcomputermuseum/ContrAlto https://github.com/livingcomputermuseum/ContrAlto