The command line interface has a tab-completion facility. It works not only on commands but on their arguments as well. The philosophy is that the user should be able to press the tab key when uncertain about what to type, and Simics should fill in the text or list alternatives.
address = bytes = count = cpu-name =
to indicate that these alternatives for arguments exists. Typing disassemble cp<tab> will expand to disassemble cpu-name = and a further tab will fill in the name of the CPU that is defined (or list all of them).