scsh-0.5/vm/arch.scm

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; -*- Mode: Scheme; Syntax: Scheme; Package: Scheme; -*-
; Copyright (c) 1992 by Richard Kelsey and Jonathan Rees. See file COPYING.
; This is file arch.scm.
;;;; Architecture description
; Things that the VM and the runtime system both need to know.
(define bits-used-per-byte 8)
; Maximum number of arguments that can be pushed on the stack to make a call,
; also the maximum number of arguments + temporaries allowed on the stack.
(define maximum-stack-args 63)
; Bytecodes: for compiler and interpreter
; Instruction specification is
; (op . args)
; OP may be a name or a list of names
; ARGS are
; nargs - a byte
; byte - a byte
; index - a byte indexing into the current template
; offset - two bytes giving an offset into the current instruction stream
; stob - a byte specifying a type for a stored object
; 0 1 2 ... - the number of non-instruction-stream arguments (some
; instructions take a variable number of arguments; the first
; number is the argument count implemented by the VM)
; + - any number of additional arguments are allowed
(define-syntax define-instruction-set
(lambda (form rename compare)
(let ((data (do ((data (reverse (cdr form)) (cdr data))
(new '() (let ((next (car data)))
(if (pair? (car next))
(append (map (lambda (op)
(cons op (cdr next)))
(car next))
new)
(cons next new)))))
((null? data) new))))
`(begin (define-enumeration op
,(map car data))
(define opcode-arg-specs
'#(,@(map cdr data)))))))
(define-instruction-set
(check-nargs= nargs) ; error if *nargs* not= operand
(check-nargs>= nargs) ; error if *nargs* < operand
(nargs) ; move *nargs* to *val*
(make-env nargs) ; cons an environment
(make-heap-env nargs) ; cons an environment in the heap
(pop-env) ; use superior env
(make-rest-list nargs +) ; pop all but nargs things off the stack
; into a list
(literal index) ; value to *val*
(local byte byte) ; back and over
((local0 local1 local2)
byte) ; back encoded into op-code for efficiency
(set-local! byte byte 1) ; back over value
(global index) ; value to *val*
(set-global! index 1)
(closure index) ; use environment in *env*
(push 1) ; push *val* onto stack
(pop) ; pop top of stack into *val*
(stack-ref byte) ; index'th element of stack into *val*
(stack-set! byte 1) ; *val* to index'th element of stack
(make-cont offset nargs) ; save state in *cont*
(current-cont) ; copy *cont* to *val*, use WITH-CONTINUATION
; to use copied continuation
(get-cont-from-heap) ; copy next continuation from heap (this
; op-code is used internally by the VM)
;; five different ways to call procedures
(call nargs 1 +) ; last argument it the procedure to call
(move-args-and-call nargs 1 +) ; same, move args to just above *cont* first
(apply nargs 1 +) ; last argument is a list of additional
; arguments, second to last is procedure to
; call
(with-continuation 2) ; first arg is cont, second is procedure
(call-with-values +) ; values are on stack, consumer is in the
; continuation pointed to by *cont*
;; Three different ways to return from calls and one way to ignore any
;; returned values
(return 1) ; return to continuation in *cont*
(values +) ; values are on stack, count is in *nargs*
(return-values nargs +) ; values are on stack, count is next byte
(ignore-values +) ; ignore (and dispose of) returned values
;; Five different ways to jump
(goto-template index) ; jump to another template
; does not poll for interrupts
(call-template nargs index) ; call a template instead of a procedure
; nargs is needed for interrupt handling
(jump-if-false offset 1) ; boolean in *val*
(jump offset)
(computed-goto byte offset 1) ; jump using delta specified by *val*
; default to instruction after deltas
;; Scalar primitives
(eq? 2)
((number? integer? rational? real? complex? exact?) 1)
((exact->inexact inexact->exact) 1)
((+ *) 2 0 1 +)
((- /) 2 1)
((= <) 2 +)
((quotient remainder) 2)
((floor numerator denominator
real-part imag-part
exp log sin cos tan asin acos sqrt
angle magnitude)
1)
(atan 2)
((make-polar make-rectangular) 2)
(bitwise-not 1)
((bitwise-and bitwise-ior bitwise-xor) 2)
(arithmetic-shift 2)
(char? 1)
((char=? char<?) 2)
((char->ascii ascii->char) 1)
(eof-object? 1)
;; Data manipulation
(stored-object-has-type? stob 1)
(stored-object-length stob 1)
(make-stored-object byte stob)
(stored-object-ref stob byte 1) ; byte is the offset
(stored-object-set! stob byte 2)
(make-vector-object stob 2) ; size + init
(stored-object-indexed-ref stob 2) ; vector + offset
(stored-object-indexed-set! stob 3) ; vector + offset + value
(make-code-vector 2)
(code-vector-length 1)
(code-vector-ref 2)
(code-vector-set! 3)
(make-string 2)
(string-length 1)
(string-ref 2)
(string-set! 3)
(location-defined? 1)
(set-location-defined?! 2)
((immutable? make-immutable!) 1)
;; I/O
(open-port 2)
((close-port input-port? output-port?) 1)
((read-char peek-char char-ready?) 1 0)
(write-char 2 1)
(write-string 2)
(force-output 1)
;; Misc
((unassigned unspecific))
(trap 1) ; raise exception specified by argument
(false) ; return #f (for bootstrapping)
(write-image 3)
(collect)
(memory-status 2)
(find-all-symbols 1) ; puts the symbols in a table
(find-all-xs 1) ; returns a vector containing all Xs
(get-dynamic-state)
(set-dynamic-state! 1)
(set-exception-handler! 1)
(set-interrupt-handlers! 1)
(set-enabled-interrupts! 1)
(return-from-interrupt)
(schedule-interrupt 1)
(external-lookup 1)
(external-call 1 +)
(time 2)
(vm-extension 2) ; access to extensions of the virtual machine
(vm-return 2) ; return from the vm in a restartable fashion
;; Unnecessary primitives
(string=? 2)
(string-hash 1)
(reverse-list->string 2)
(intern 2)
)
(define-enumeration interrupt
(alarm ; order matters - higher priority first
keyboard
memory-shortage
))
; Options for op/time
(define-enumeration time-option
(ticks-per-second
run-time
real-time
))
; Options for op/memory-status
(define-enumeration memory-status-option
(available
heap-size
stack-size
set-minimum-recovered-space!
gc-count
))
(define-enumeration stob
(;; D-vector types (traced by GC)
pair
symbol
vector
closure
location
port
ratio
record
continuation
extended-number
template
weak-pointer
external
unused-d-header1
unused-d-header2
;; B-vector types (not traced by GC)
string ; = least b-vector type
code-vector
double ; double precision floating point
bignum
))
; This is here to try to ensure that it is changed when STOB changes.
(define least-b-vector-type (enum stob string))
; (stob predicate constructor . (accessor modifier)*)
; If nothing else, the runtime system and the VM need to agree on
; which slot of a pair is the car and which is the cdr.
(define stob-data
'((pair pair? cons
(car set-car!) (cdr set-cdr!))
(symbol symbol? make-symbol ; symbols actually made using op/intern
(symbol->string #f))
(location location? make-location
(contents set-contents!) (location-id set-location-id!))
(closure closure? make-closure
(closure-template #f) (closure-env #f))
(weak-pointer weak-pointer? make-weak-pointer
(weak-pointer-ref #f))
(external external? make-external
(external-name #f) (external-value #f))
))