8 Mar
2011
8 Mar
'11
11:08 a.m.
Tony Duell wrote:
What do you mean by 'instruction set'. In particular, what do you do
about machines (PERQ, for example) that load their microocde at power-on
and thus don't have a fixed machine code instrcution set.
-tony
What do you mean by 'hardware' multiply
and divide? A number of machines,
I suspect the 6809 is amongst them, had no particualrl hardware for
multiply or divide, but they did have multiply and maybe divide
instrucitons in the instruction setc. These instrucitons were implemented
by microcode using the normal registers and ALU. Does that count?
Yes, anything that includes a dedicated multiply or divide instruction as part
of the instruction set; I suspect a lot of the early implementations fall into
the "simple shift-add" that I mentioned due to the lack/cost of silicon.