Design of the SCHEME-78 Lisp-based microprocessor (1980)
10 points by veqq
10 points by veqq
What struck me about this is that the chip area is split very close to 50-50 between useful work and garbage collection.
The SCHEME-78 design doesn't have a on-chip garbage collector: the misleadingly labelled GC areas are more like an ALU in that they implement the Scheme cons/car/cdr primitive operations.
Oh, so it does (I admit I only skimmed the paper!)
It says,
In point of fact, in the prototype processor, the storage manager includes no garbage collector. The prototype was one project of a "project set" including some two dozen separate circuits, all of which had to be fit onto a single chip together. This imposed severe area limitations which restricted the address size to eight bits and required the elimination of the microcode for the garbage collector. However, space for microcode was the only limitation; all the other necessary structures for garbage collection were in the design. The complexity of a full garbage collector is comparable to that of the evaluator shown above.