; -*- Mode: Scheme; Syntax: Scheme; Package: Scheme; -*-

; This is file vm.scm.

;;;; Interface definitions for virtual machine

;(define-signature ascii-sig
;  (values ascii->char char->ascii))

; Bare-machine signature
;  Things defined externally to the VM proper (by Scheme or
;  features.scm or ascii.scm).

(define-signature bare-machine-sig
  (values
    not
    unassigned
    error
    assert
    +& -& *& <& <=& =& >=& >& quotient& remainder&
    adjoin-bits low-bits high-bits
    logand			;2nd arg is always 2^k-1
    expt			;1st arg is always 2
    ascii->char char->ascii
    char=? char<?

    define-enumeration
    goto computed-goto label run-machine halt-machine
    make-dispatch-table define-dispatch! dispatch

    ;; The following are only used for checking for overflow!
    + - * < <= = >= > quotient remainder

    %make-vector %vector-ref %vector-set! %vector-length
    %vector-posq
    %make-string %string-set!		;for extract-string

    ;; I/O
    ;; These names should have %'s in front, shouldn't they?
    read-char write-char write-string
    newline
    eof-object?
    open-input-file open-output-file
    close-input-port close-output-port
    current-input-port current-output-port

    ;; Used only by READ-IMAGE and WRITE-IMAGE
    write read
    call-with-output-file call-with-input-file ;ditto
    ))

; Data-manipulation subsystem

(define-signature data-sig
  (values
    ;; Scalar stuff
    eq?
    fixnum? enter-fixnum extract-fixnum
    false? false true null enter-boolean
    unspecified eof-object
    undefined? unbound-marker unassigned-marker quiescent
    char? enter-char extract-char

    ;; Allocated things
    create-memory initialize-heap *root*
    collect write-image read-image *finished* *filename*
    available?
    pair? cons car cdr set-car! set-cdr! pair-size
      length
    symbol? intern symbol->string symbol-size
    cell? lookup cell-name contents set-contents! cell-size
    closure? make-closure closure-env closure-template closure-size
    code-vector? make-code-vector code-vector-length
      code-vector-ref code-vector-set! code-vector-size
    string? make-string string-length string-ref string-set!
      extract-string string-size
    vector? make-vector vector-length vector-ref vector-set!
      vector vector-fill! vector-size

    ;; Stack allocated things
    push pop push-size
    push-vector pop-vector stack-vector-size
    set-stack! available-on-stack?

    ;; An unprincipled assortment of I/O routines
    initialize-i/o-system
    create-initial-ports
    port? make-port port-size
    port-mode for-input for-output open?
    port-index find-port-index use-port-index!
    extract-port
    peeked-char set-peeked-char!
    close-port
    ))

; VM-SIG
;  The interpreter

(define-signature vm-sig
  (values
    start-vm   ;from boot
    resume
    get-symbol-table
    get-system-environment
    clear-registers
    initialize-machine
    ))

; Features

(define-signature features-sig
  (values
    vector-posq string-posq
    make-fluid fluid set-fluid! let-fluid
    make-table table-ref table-set!
    make-code-vector code-vector? code-vector-ref
    code-vector-set! code-vector-length
    make-cell cell? contents set-contents! cell-name
    make-empty-environment
    system-environment
    lookup
    concatenate-symbol
    eval user-initial-environment   ;from pseudoscheme
    ))

; Compiler

(define-signature comp-sig
  (values
    parse-top-level-form
    compile-top
    ;; Stuff for block compiler?  define-rewriter, etc.?
    ))

(define-signature boot-sig
  (values
    init
    cold-load
    run
    initialize-memory))