More opcodes
| author |
Steve Losh <steve@stevelosh.com> |
| date |
Wed, 16 Nov 2016 20:54:13 +0000 |
| parents |
5cfbf08cb54d |
| children |
8e58d7eb4d03 |
(in-package :chip8)
(setf *print-length* 10)
(setf *print-base* 10)
(declaim (optimize (speed 1) (safety 3) (debug 3)))
(declaim (optimize (speed 3) (safety 0) (debug 3)))
;;;; Types --------------------------------------------------------------------
(deftype int8 () '(unsigned-byte 8))
(deftype int12 () '(unsigned-byte 12))
(deftype int16 () '(unsigned-byte 16))
(deftype basic-array (element-type size)
`(simple-array ,(upgraded-array-element-type element-type) (,size)))
(deftype stack (size)
`(vector ,(upgraded-array-element-type 'int12) ,size))
;;;; Utils --------------------------------------------------------------------
(declaim (inline not= +_8 -_8 chop cat-bytes))
(defun make-simple-array (element-type size &rest args)
(apply #'make-array size
:adjustable nil
:fill-pointer nil
:element-type element-type
args))
(defun not= (x y)
(not (= x y)))
(defun chop (size integer)
(ldb (byte size 0) integer))
(defun cat-bytes (high-order low-order)
(dpb high-order (byte 8 8) low-order))
(defun +_8 (x y)
(let ((result (+ x y)))
(values (chop 8 result)
(if (> result 255) 1 0))))
(defun -_8 (x y)
(let ((result (- x y)))
(values (chop 8 result)
(if (> x y) 1 0))))
(defmacro macro-map ((lambda-list items) &rest body)
(with-gensyms (macro)
`(macrolet ((,macro ,(ensure-list lambda-list) ,@body))
,@(iterate (for item :in items)
(collect `(,macro ,@(ensure-list item)))))))
;;;; Data ---------------------------------------------------------------------
(defstruct (chip (:constructor make-chip%))
(memory (make-simple-array 'int8 4096)
:type (basic-array int8 4096)
:read-only t)
(registers (make-simple-array 'int8 16)
:type (basic-array int8 16)
:read-only t)
(keys (make-simple-array 'boolean 16)
:type (basic-array boolean 16)
:read-only t)
(awaiting-key nil
:type (or null (integer 0 15)))
(video-raw (error "Required")
:type (basic-array fixnum #.(* 32 64))
:read-only t)
(video (error "Required")
:type (array fixnum (32 64)) ; row major :\
:read-only t)
(video-dirty t :type boolean)
(index 0 :type int16)
(program-counter 0 :type int12)
(delay-timer 0 :type int8)
(sound-timer 0 :type int8)
(random-state (make-random-state t)
:type random-state
:read-only t)
(stack (make-array 16
:adjustable nil
:fill-pointer 0
:element-type 'int12)
:type (stack 16)))
(defun make-chip ()
(let* ((video-raw (make-simple-array 'fixnum (* 32 64)))
(video (make-array '(32 64)
:displaced-to video-raw
:element-type 'fixnum)))
(make-chip% :video-raw video-raw :video video)))
(define-with-macro chip
memory registers
index program-counter
delay-timer sound-timer
random-state
video video-raw video-dirty
keys awaiting-key
stack)
;;;; Graphics -----------------------------------------------------------------
(defmacro vref (video x y)
`(aref ,video ,y ,x))
;;;; Keyboard -----------------------------------------------------------------
(defun keydown (chip key)
(with-chip (chip)
(setf (aref keys key) t)
(when awaiting-key
(setf (aref registers awaiting-key) key
awaiting-key nil))))
(defun keyup (chip key)
(setf (aref (chip-keys chip) key) nil))
;;;; Opcodes ------------------------------------------------------------------
(eval-when (:compile-toplevel :load-toplevel :execute)
(defun parse-opcode-argument-bindings (argument-list)
(flet ((normalize-arg (arg)
(destructuring-bind (symbol &optional (nibbles 1))
(ensure-list arg)
(list symbol nibbles))))
(iterate
(for (symbol nibbles) :in (mapcar #'normalize-arg argument-list))
(for position :first 3 :then (- position nibbles))
(when (not (eql symbol '_))
(collect `(,symbol (ldb (byte ,(* nibbles 4)
,(* position 4))
opcode))))))))
(defmacro define-opcode (name argument-list &body body)
`(progn
(declaim (ftype (function (chip int16)
(values null &optional))
,name))
(defun ,name (chip opcode)
(declare (ignorable opcode))
(with-chip (chip)
(macrolet ((register (index)
`(aref registers ,index)))
(let ,(parse-opcode-argument-bindings argument-list)
,@body))
nil))))
(macro-map ;; LD ...
((name arglist destination source)
((op-ld-i<imm (_ (value 3)) index value)
(op-ld-reg<imm (_ r (value 2)) (register r) value)
(op-ld-reg<reg (_ rx ry _) (register rx) (register ry))
(op-ld-reg<dt (_ r _ _) (register r) delay-timer)
(op-ld-dt<reg (_ r _ _) delay-timer (register r))
(op-ld-st<reg (_ r _ _) sound-timer (register r))))
`(define-opcode ,name ,arglist
(setf ,destination ,source)))
(define-opcode op-cls () ;; CLS
(fill video-raw 0)
(setf video-dirty t))
(define-opcode op-jp-imm (_ (target 3)) ;; JP addr
(setf program-counter target))
(define-opcode op-jp-imm+reg (_ (target 3)) ;; JP V_0 + addr
(setf program-counter (+ target (register 0))))
(define-opcode op-call (_ (target 3)) ;; CALL addr
(vector-push program-counter stack)
(setf program-counter target))
(define-opcode op-ret () ;; RET
(setf program-counter (vector-pop stack)))
(macro-map ;; ADD/SUB (8-bit)
((name op source-arg source-expr)
((op-add-reg<imm +_8 (immediate 2) immediate)
(op-add-reg<reg +_8 (ry 1) (register ry))
(op-sub-reg<reg -_8 (ry 1) (register ry))))
`(define-opcode ,name (_ rx ,source-arg)
(multiple-value-bind (result carry)
(,op (register rx) ,source-expr)
(setf (register rx) result
(register #xF) carry))))
(define-opcode op-add-index<reg (_ r) ;; ADD I, Vx (16-bit)
(zapf index (chop 16 (+ % (register r)))))
(define-opcode op-subn-reg<reg (_ rx ry) ;; SUBN
(multiple-value-bind (result carry)
(-_8 (register ry) (register rx)) ; subtraction order is swapped for SUBN
(setf (register rx) result
(register #xF) carry)))
(macro-map ;; SE/SNE
((name test x-arg y-arg)
((op-se-reg-imm = (r 1) (immediate 2))
(op-sne-reg-imm not= (r 1) (immediate 2))
(op-se-reg-reg = (rx 1) (ry 1))
(op-sne-reg-reg not= (rx 1) (ry 1))))
`(define-opcode ,name (_ ,x-arg ,y-arg)
(when (,test ,(car x-arg) ,(car y-arg))
(incf program-counter 2))))
(macro-map ;; AND/OR/XOR
((name function)
((op-or logior)
(op-and logand)
(op-xor logxor)))
`(define-opcode ,name (_ destination source _)
(zapf (register destination)
(,function % (register source)))))
(define-opcode op-rnd (_ r (mask 2)) ;; RND
(setf (register r)
(logand (random 256 random-state) mask)))
(define-opcode op-skp (_ r _ _) ;; SKP
(when (aref keys (register r))
(incf program-counter 2)))
(define-opcode op-sknp (_ r _ _) ;; SKNP
(when (not (aref keys (register r)))
(incf program-counter 2)))
(define-opcode op-ld-mem<regs (_ n _ _) ;; LD [I] < V_n
(replace memory registers :start1 index :end2 n))
(define-opcode op-ld-regs<mem (_ n _ _) ;; LD V_n < [I]
(replace registers memory :end1 n :start2 index))
(define-opcode op-ld-reg<key (_ r _ _) ;; LD Vx, Key (await)
(setf awaiting-key r))
(define-opcode op-unknown ((instruction 4))
(error "Unknown instruction: #x~4,'0X" instruction))
;;;; Main ---------------------------------------------------------------------
(declaim
(ftype (function (chip) null) emulate-cycle)
(ftype (function (chip int16) null) dispatch-instruction))
(defparameter *running* t)
(defparameter *paused* nil)
(defparameter *c* nil)
(defun load-rom (chip filename)
(replace (chip-memory chip) (read-file-into-byte-vector filename)
:start1 #x200))
(defun dispatch-instruction (chip instruction)
(macrolet ((call (name) `(,name chip instruction)))
(ecase (logand #xF000 instruction)
(#x0 (ecase instruction
(#x00E0 (call op-cls))
(#x00EE (call op-ret))))
(#x1 (call op-jp-imm))
(#x2 (call op-call))
(#x3 (call op-se-reg-imm))
(#x4 (call op-sne-reg-imm))
(#x5 (ecase (logand #x000F instruction)
(#x0 (call op-se-reg-reg))))
(#x6 (call op-ld-reg<imm))
(#x7 (call op-add-reg<imm))
(#x8 (ecase (logand #x000F instruction)
(#x0 (call op-ld-reg<reg))
(#x1 (call op-or))
(#x2 (call op-and))
(#x3 (call op-xor))
(#x4 (call op-add-reg<reg))
(#x5 (call op-sub-reg<reg))
(#x6)
(#x7 (call op-subn-reg<reg))
(#xE)))
(#x9 (ecase (logand #x000F instruction)
(#x0 (call op-sne-reg-reg))))
(#xA (call op-ld-i<imm))
(#xB (call op-jp-imm+reg))
(#xC (call op-rnd))
(#xD)
(#xE (ecase (logand #x00FF instruction)
(#x9E (call op-skp))
(#xA1 (call op-sknp))))
(#xF (ecase (logand #x00FF instruction)
(#x07 (call op-ld-reg<dt))
(#x0A (call op-ld-reg<key))
(#x15 (call op-ld-dt<reg))
(#x18 (call op-ld-st<reg))
(#x1E (call op-add-index<reg))
(#x29)
(#x33)
(#x55 (call op-ld-mem<regs))
(#x65 (call op-ld-regs<mem)))))))
(defun emulate-cycle (chip)
(with-chip (chip)
(if awaiting-key
(sleep 10/1000)
(let ((instruction (cat-bytes (aref memory program-counter)
(aref memory (1+ program-counter)))))
(zapf program-counter (chop 12 (+ % 2)))
(dispatch-instruction chip instruction)))))
(defun run ()
(let ((chip (make-chip)))
(setf *running* t
*c* chip)
(chip8.gui::run-gui chip)
;; init
;; load rom
#+no(iterate
(while *running*)
(emulate-cycle chip)
(handle-keys chip)
)
)
)