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                              EULERLISP VM

                              Leon Rische
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                         [2019-08-18 Sun 19:40]


Table of Contents
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1. Arithmetic Primitives


The EulerLisp VM is *stack-based* and has one operand register.


1 Arithmetic Primitives
=======================

  Arithmetic primitives work by assigning `val' to the result of
  combining `val' and `arg1' using the given primitive.

  `(+ a b)' compiles to

  ,----
  | <Code for b>
  | PUSH_VAULE
  | <Code for a>
  | POP_ARG1
  | ADD
  `----

  Arguments are evaluated from right to left and pushed to the stack,
  then popped to `arg1' one by one. This is important for primitives
  that are not commutative, e.g. `/'.

  This easily extends to an arbitrary number of arguments.

  Consider `(+ a b c d)' which compiles to

  ,----
  | <Code for d>
  | PUSH_VAULE
  | <Code for c>
  | PUSH_VAULE
  | <Code for b>
  | PUSH_VAULE
  | <Code for a>
  | POP_ARG1
  | ADD
  | POP_ARG1
  | ADD
  | POP_ARG1
  | ADD
  `----

  Previously, primitives with more than two arguments were implemented
  using builtin functions. The changes in performance are negligible
  since arithmetic primitives with more than two arguments are rarely
  used.

  Running Project Euler Problems 1 to 50: Before: 29.446s / 30.340s /
  29.978s After: 28.455s / 28.356s / 29.118s