5 ms·
I keep reading papers on stack-based vs register-based architectures, and it's clear there's no "conclusive" right-answer. But I think it's pretty telling that
by kjs3 7y ago
I keep reading papers on stack-based vs register-based architectures, and it's clear there's no "conclusive" right-answer. But I think it's pretty telling that very little looks like a B5000, and an awful lot looks like a PDP-11/S360. Maybe the Forth faithful are right and the rest of us are too dumb to 'get' stack-based, but it's pretty clear what the market decided.
- RodgerTheGreat 7y agoThe B5000 does not closely resemble a Forth machine. It is stack-oriented, but does not contain separate parameter and return stacks which may grow and shrink independently. You could perhaps argue that the JVM and its peers are the modern-day successors to the B5000.
- kjs3 7y agoThat wasn't the point. The point is that most of the field abandoned stack hardware for register hardware, upon which all sorts of software paradigms are implemented.
- kragen 7y agoSounds like somebody hasn't read Koopman yet.
- kjs3 7y agoI've read Koopman; fascinating stuff. Really solidified my understanding of the use of multiple stacks in Forth-like environments. But I think it's instructive that none of the commercial architectures he describes (from 1989) have a contemporary descendant (although I think you can still get the RTX 2000 as a space-rated special order at an astronomical unit price). I think that tends to support my premise.
- kragen 7y agoThat's reasonable. I thought you were talking about things like the B5000 and the 8087.
- kjs3 7y agoWell...I can. The 8087 was basically obsoleted by register-based SSE2 and SSE3, and as I understand on x86_64 the vestigial 8087 op codes are decoded microinstructions executed by the SSEx unit. And the descendant of the B5000 (now called Unisys ClearPath) is a VM running on Xeons; they stopped making stack-based MCP processors in 2015 or so. So I think the original point still stands.