Cleavir VS Clostrum

Clasp notably uses Cleavir which is “an implementation-independent framework for creating Common Lisp compilers”.

I think something similar has come up with the Cleavir framework; there are currently separate instruction types for arithmetic operations, but it has been proposed to replace them with fewer types, because there is little use in specific types. Register allocation is specified the hard way currently, while as you say, the complexity even for x86-64's multiplication and division instructions is just in forcing use of the right input and output registers.

This is a project that has been in development for years now and also makes use of the Cleavir compiler framework (https://github.com/s-expressionists/Cleavir), which is being developed as part of another new Common Lisp implementation called SICL (https://github.com/robert-strandh/SICL).

Congrats to the CLASP devs, this is a huge accomplishment and it's really exciting to see a new CL implementation get a 1.0 release.

There is significant overlap with SICL and its associated pieces which supply many of the other parts needed to make a Common Lisp. Some of these are Cluster which provides a portable and extensible assembler, Eclector which supplies a portable and extensible reader, Concrete-Syntax-Tree that supports source code tracking during compilation, ctype that implements the Common Lisp type system, and Clostrum that provides first-class environments for e.g. run-time, evaluation, and compilation. The SICL project has as one of its goals the creation of portable infrastructure for implementing Common Lisp, and these pieces are novel building blocks that were created as part of the project.