src/wam/constants.lisp @ fb3a334a14f3
Refactor the shared variables copypasting
author |
Steve Losh <steve@stevelosh.com> |
date |
Mon, 18 Apr 2016 15:38:02 +0000 |
parents |
902d171a1a85 |
children |
d8dc03903456 |
(in-package #:bones.wam)
(define-constant +cell-width+ 16
:documentation "Number of bits in each heap cell.")
(define-constant +cell-tag-width+ 2
:documentation "Number of bits reserved for cell type tags.")
(define-constant +cell-value-width+ (- +cell-width+ +cell-tag-width+)
:documentation "Number of bits reserved for cell values.")
(define-constant +cell-tag-bitmask+ #b11
:documentation "Bitmask for masking the cell type tags.")
(define-constant +heap-limit+ (expt 2 +cell-value-width+)
;; We can only address 2^value-bits cells.
:documentation "Maximum size of the WAM heap.")
(define-constant +code-word-size+ 16
:documentation "Size (in bits) of each word in the code store.")
(define-constant +code-limit+ (expt 2 +code-word-size+)
:documentation "Maximum size of the WAM code store.")
(define-constant +code-sentinal+ (1- +code-limit+)
:documentation "Sentinal value used in the PC and CP.")
(define-constant +tag-null+ #b00
:documentation "An empty cell.")
(define-constant +tag-structure+ #b01
:documentation "A structure cell.")
(define-constant +tag-reference+ #b10
:documentation "A pointer to a cell.")
(define-constant +tag-functor+ #b11
:documentation "A functor.")
(define-constant +functor-arity-width+ 4
:documentation "Number of bits dedicated to functor arity.")
(define-constant +functor-arity-bitmask+ #b1111
:documentation "Bitmask for the functor arity bits.")
(define-constant +register-count+ 16
:documentation "The number of registers the WAM has available.")
(define-constant +maximum-arity+ (1- (expt 2 +functor-arity-width+))
:documentation "The maximum allowed arity of functors.")
(define-constant +maximum-query-size+ 256
:documentation
"The maximum size (in bytes of bytecode) a query may compile to.")
(define-constant +tag-local-register+ #b0
:documentation "A local register (X_n or A_n).")
(define-constant +tag-stack-register+ #b1
:documentation "A stack register (Y_n).")
(define-constant +stack-word-size+ 16
:documentation "Size (in bits) of each word in WAM stack.")
(define-constant +stack-limit+ (expt 2 +stack-word-size+)
;; We can only address 2^value-bits cells, and since stack address are
;; themselves stored on the stack (the environment continuation pointer) they
;; can only reference so much memory.
;;
;; todo: we might want to limit this further to prevent the stack from growing
;; too large.
:documentation "Maximum size of the WAM stack.")
(define-constant +stack-frame-size-limit+ (+ 3 +register-count+)
:documentation "The maximum size, in stack frame words, that a stack frame could be.")
;;;; Opcodes
;;; Program
(define-constant +opcode-get-structure-local+ 0)
(define-constant +opcode-unify-variable-local+ 1)
(define-constant +opcode-unify-variable-stack+ 2)
(define-constant +opcode-unify-value-local+ 3)
(define-constant +opcode-unify-value-stack+ 4)
(define-constant +opcode-get-variable-local+ 5)
(define-constant +opcode-get-variable-stack+ 6)
(define-constant +opcode-get-value-local+ 7)
(define-constant +opcode-get-value-stack+ 8)
;;; Query
(define-constant +opcode-put-structure-local+ 9)
(define-constant +opcode-set-variable-local+ 10)
(define-constant +opcode-set-variable-stack+ 11)
(define-constant +opcode-set-value-local+ 12)
(define-constant +opcode-set-value-stack+ 13)
(define-constant +opcode-put-variable-local+ 14)
(define-constant +opcode-put-variable-stack+ 15)
(define-constant +opcode-put-value-local+ 16)
(define-constant +opcode-put-value-stack+ 17)
;;; Control
(define-constant +opcode-call+ 18)
(define-constant +opcode-proceed+ 19)
(define-constant +opcode-allocate+ 20)
(define-constant +opcode-deallocate+ 21)
;;;; Debug Config
(defparameter *off-by-one* nil)