https://github.com/dym/movitz https://github.com/dym/movitz is a Common Lisp system that runs on bare metal x86. The source code is quite readable. The rest of

https://github.com/dym/movitz https://github.com/dym/movitz is a Common Lisp system that runs on bare metal x86. The source code is quite readable. The rest of this post is an excerpt from an email I sent 6 years ago. The following comments on runtime systems are partially based on a long c.l.l thread with posts by Lucid, Symbolics, and Franz alumni. Franz uses a 3-layer approach: CL, a low-level Lisp, and C. Lucid started with Lisp that generated assembler but reluctantly added some C. Symbolics Lisp Machines used bootstrap code in a Pascal-level language with prefix syntax. A Symbolics alum said that in retrospect they should have used C. Most Lisp implementations have subprimitives - low-level functions that can circumvent the type system, often with a prefix such as % or :. Assembly language integration dates to Lisp 1.5 and there are several common approaches. 1. turn the optimizer off - this is easy to use and implement. 2. optimize the assembler block - Naughty Dog GOAL did this. 3. annotate the assembler block with pragmas that indicate side effects. This can be error prone and difficult to use. https://www.pvk.ca/Blog/2014/08/16/how-to-define-new-intrinsics-in-sbcl/ https://www.pvk.ca/Blog/2014/08/16/how-to-define-new-intrins... is an example of this approach. Edited to add the SBCL intrinsic link.