InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/bsd_srcs/usr.bin/lisp/liszt/funa.l

Text File | 1987-12-15 | 31.0 KB | 934 lines

(include-if (null (get 'chead 'version)) "../chead.l")
(Liszt-file funa
   "$Header: funa.l,v 1.12 87/12/15 17:02:01 sklower Exp $")

;;; ----    f u n a                function compilation
;;;
;;;                -[Mon Aug 22 22:01:01 1983 by layer]-


;--- cc-and :: compile an and expression
; We evaluate forms from left to right as long as they evaluate to
; a non nil value.  We only have to worry about storing the value of
; the last expression in g-loc.
;
(defun cc-and nil
  (let ((finlab (d-genlab))
    (finlab2)
    (exps (if (cdr v-form) thenret else '(t))))    ; (and) ==> t
       (if (null (cdr g-cc))
       then (d-exp (do ((g-cc (cons nil finlab))
                (g-loc)
                (g-ret)
                (ll exps (cdr ll)))
               ((null (cdr ll)) (car ll))
               (d-exp (car ll))))
        (if g-loc
            then (setq finlab2 (d-genlab))
             (e-goto finlab2)
             (e-label finlab)
             (d-move 'Nil g-loc)
             (e-label finlab2)
            else (e-label finlab))
       else ;--- cdr g-cc is non nil, thus there is
        ; a quick escape possible if one of the
        ; expressions evals to nil

        (if (null g-loc) then (setq finlab (cdr g-cc)))
            (d-exp (do ((g-cc (cons nil finlab))
                (g-loc)
                (g-ret)
                (ll exps (cdr ll)))
               ((null (cdr ll)) (car ll))
               (d-exp (car ll))))
        ; if g-loc is non nil, then we have evaled the and
        ; expression to yield nil, which we must store in
        ; g-loc and then jump to where the cdr of g-cc takes us
        (if g-loc
            then (setq finlab2 (d-genlab))
             (e-goto finlab2)
             (e-label finlab)
             (d-move 'Nil g-loc)
             (e-goto (cdr g-cc))
             (e-label finlab2))))
  (d-clearreg))     ; we cannot predict the state of the registers

;--- cc-arg  :: get the nth arg from the current lexpr
;
; the syntax for Franz lisp is (arg i)
; for interlisp the syntax is (arg x i) where x is not evaluated and is
; the name of the variable bound to the number of args.  We can only handle
; the case of x being the variable for the current lexpr we are compiling
;
(defun cc-arg nil
   (prog (nillab finlab)
       (setq nillab (d-genlab)
         finlab (d-genlab))
       (if (not (eq 'lexpr g-ftype))
       then (comp-err " arg only allowed in lexprs"))
       (if (and (eq (length (cdr v-form)) 2) fl-inter)
       then (if (not (eq (car g-args) (cadr v-form)))
            then (comp-err " arg expression is for non local lexpr "
                   v-form)
            else (setq v-form (cdr v-form))))
       (if (and (null g-loc) (null g-cc))
       then ;bye bye, wouldn't do anything
        (return nil))
       (if (and (fixp (cadr v-form)) (>& (cadr v-form) 0))
       then ; simple case (arg n) for positive n
        (d-move `(fixnum ,(cadr v-form)) 'reg)
        #+for-68k
        (progn
            (e-sub `(-4 #.olbot-reg) 'd0)
            (if g-loc
            then (e-move '(% -8 #.olbot-reg d0) (e-cvt g-loc)))
            (if g-cc then (e-cmpnil '(% -8 #.olbot-reg d0))))
        #+(or for-vax for-tahoe)
        (progn
            (e-sub3 '(* -4 #.olbot-reg) '(0 r0) 'r0)
            (if g-loc
            then (e-move '(-8 #.olbot-reg r0) (e-cvt g-loc))
             elseif g-cc
            then (e-tst '(-8 #.olbot-reg r0))))
        (d-handlecc)
    elseif (or (null (cadr v-form))
           (and (fixp (cadr v-form)) (=& 0 (cadr v-form))))
       then ;---the form is: (arg nil) or (arg) or (arg 0).
        ;   We have a private copy of the number of args right
        ; above the arguments on the name stack, so that
        ; the user can't clobber it... (0 olbot) points
        ; to the user setable copy, and (-4 olbot) to our
        ; copy.
        (if g-loc then (e-move '(-4 #.olbot-reg) (e-cvt g-loc)))
        ;   Will always return a non nil value, so
        ; don't even test it.
        (if (car g-cc) then (e-goto (car g-cc)))
       else ; general (arg <form>)
        (let ((g-loc 'reg)
              (g-cc (cons nil nillab))
              (g-ret))
            (d-exp (cadr v-form)))  ;boxed fixnum or nil
        ; (arg 0) returns nargs (compiler only!)
        (d-cmp 'reg '(fixnum 0))
        (e-gotonil nillab)

        ; ... here we are doing (arg <number>), <number> != 0
        #+for-68k
        (progn
            (e-sub '(-4 #.olbot-reg) 'd0)
            (if g-loc
            then (e-move '(% -8 #.olbot-reg d0) (e-cvt g-loc)))
            (if g-cc then (e-cmpnil '(% -8 #.olbot-reg d0))))
        #+(or for-vax for-tahoe)
        (progn
            (e-sub3 `(* -4 #.olbot-reg) '(0 r0) 'r0)
            (if g-loc
            then (e-move '(-8 #.olbot-reg r0) (e-cvt g-loc))
             elseif g-cc
            then (e-tst '(-8 #.olbot-reg r0))))
        (d-handlecc)
        (e-goto finlab)
        (e-label nillab)
        ; here we are doing (arg nil) which
        ; returns the number of args
        ; which is always true if anyone is testing
        (if g-loc
            then (e-move '(-4 #.olbot-reg) (e-cvt g-loc))
             #+for-68k (if g-cc then (e-cmpnil '(-4 #.olbot-reg)))
             (d-handlecc)
         elseif (car g-cc)
            then (e-goto (car g-cc))) ;always true
        (e-label finlab))))

;--- c-assembler-code
; the args to assembler-code are a list of assembler language
; statements.  This statements are put directly in the code
; stream produced by the compiler.  Beware: The interpreter cannot
; interpret the assembler-code function.
;
(defun c-assembler-code nil
  (setq g-skipcode nil)        ; turn off code skipping
  (makecomment '(assembler code start))
  (do ((xx (cdr v-form) (cdr xx)))
      ((null xx))
      (e-write1 (car xx)))
  (makecomment '(assembler code end)))

;--- cm-assq :: assoc with eq for testing
;
; form: (assq val list)
;
(defun cm-assq nil
  `(do ((xx-val ,(cadr v-form))
    (xx-lis ,(caddr v-form) (cdr xx-lis)))
       ((null xx-lis))
       (cond ((eq xx-val (caar xx-lis)) (return (car xx-lis))))))

;--- cc-atom :: test for atomness
;
(defun cc-atom nil
  (d-typecmplx (cadr v-form)
           #.(immed-const (plus 1_0 1_1 1_2 1_4 1_5 1_6 1_7 1_9 1_10))))

;--- c-bcdcall :: do a bcd call
;
; a bcdcall is the franz equivalent of the maclisp subrcall.
; it is called with
; (bcdcall 'b_obj 'arg1 ...)
;  where b_obj must be a binary object. no type checking is done.
;
(defun c-bcdcall nil
  (d-callbig 1 (cdr v-form) t))

;--- cc-bcdp :: check for bcdpness
;
(defun cc-bcdp nil
  (d-typesimp (cadr v-form) #.(immed-const 5)))

;--- cc-bigp :: check for bignumness
;
(defun cc-bigp nil
  (d-typesimp (cadr v-form) #.(immed-const 9)))

;--- c-boole :: compile
;
#+(or for-vax for-tahoe)
(progn 'compile
(defun c-boole nil
   (cond ((fixp (cadr v-form))
      (setq v-form (d-boolexlate (d-booleexpand v-form)))))
   (cond ((eq 'boole (car v-form))     ;; avoid recursive calls to d-exp
      (d-callbig 'boole (cdr v-form) nil))
     (t (let ((g-loc 'reg) (g-cc nil) (g-ret nil))  ; eval answer
           (d-exp v-form)))))

;--- d-booleexpand :: make sure boole only has three args
;  we use the identity (boole k x y z) == (boole k (boole k x y) z)
; to make sure that there are exactly three args to a call to boole
;
(defun d-booleexpand (form)
   (if (and (dtpr form) (eq 'boole (car form)))
       then (if (< (length form) 4)
        then (comp-err "Too few args to boole : " form)
         elseif (= (length form) 4)
        then form
        else (d-booleexpand
             `(boole ,(cadr form)
                  (boole ,(cadr form)
                      ,(caddr form)
                      ,(cadddr form))
                  ,@(cddddr form))))
       else form))

(declare (special x y))
(defun d-boolexlate (form)
   (if (atom form)
       then form
    elseif (and (eq 'boole (car form))
        (fixp (cadr form)))
       then (let ((key (cadr form))
          (x (d-boolexlate (caddr form)))
          (y (d-boolexlate (cadddr form)))
          (res))
        (makecomment `(boole key = ,key))
        (if (eq key 0)         ;; 0
            then `(progn ,x ,y 0)
         elseif (eq key 1)     ;; x * y
            then #+for-vax `(fixnum-BitAndNot ,x (fixnum-BitXor ,y -1))
                 #+for-tahoe `(fixnum-BitAnd ,x ,y)
         elseif (eq key 2)     ;; !x * y
            then #+for-vax `(fixnum-BitAndNot (fixnum-BitXor ,x -1)
                        (fixnum-BitXor ,y -1))
                 #+for-tahoe `(fixnum-BitAnd (fixnum-BitXor ,x -1) ,y)
         elseif (eq key 3)     ;; y
            then `(progn ,x ,y)
         elseif (eq key 4)    ;; x * !y
            then #+for-vax `(fixnum-BitAndNot ,x ,y)
             #+for-tahoe `(fixnum-BitAnd ,x (fixnum-BitXor ,y -1))
         elseif (eq key 5)     ;; x
            then `(prog1 ,x ,y)
         elseif (eq key 6)        ;; x xor y
            then `(fixnum-BitXor ,x ,y)
         elseif (eq key 7)     ;; x + y
            then `(fixnum-BitOr ,x ,y)
         elseif (eq key 8)    ;; !(x xor y)
            then `(fixnum-BitXor (fixnum-BitOr ,x ,y) -1)
         elseif (eq key 9)     ;; !(x xor y)
            then `(fixnum-BitXor (fixnum-BitXor ,x ,y) -1)
         elseif (eq key 10)     ;; !x
            then `(prog1 (fixnum-BitXor ,x -1) ,y)
         elseif (eq key 11)     ;; !x + y
            then `(fixnum-BitOr (fixnum-BitXor ,x -1) ,y)
         elseif (eq key 12)     ;; !y
            then `(progn ,x (fixnum-BitXor ,y -1))
         elseif (eq key 13)     ;; x + !y
            then `(fixnum-BitOr ,x (fixnum-BitXor ,y -1))
         elseif (eq key 14)     ;; !x + !y
            then `(fixnum-BitOr (fixnum-BitXor ,x -1)
                    (fixnum-BitXor ,y -1))
         elseif (eq key 15)     ;; -1
            then `(progn ,x ,y -1)
            else form))
       else form))

(declare (unspecial x y))
) ;; end for-vax


;--- c-*catch :: compile a *catch expression
;
; the form of *catch is (*catch 'tag 'val)
; we evaluate 'tag and set up a catch frame, and then eval 'val
;
(defun c-*catch nil
   (let ((g-loc 'reg)
     (g-cc nil)
     (g-ret nil)
     (finlab (d-genlab))
     (beglab (d-genlab)))
       (d-exp (cadr v-form))        ; calculate tag into 'reg
       (d-pushframe #.F_CATCH 'reg 'Nil) ; the Nil is a don't care
       (push nil g-labs)        ; disallow labels
       ; retval will be non 0 if we were thrown to, in which case the value
       ; thrown is in _lispretval.
       ; If we weren't thrown-to the value should be calculated in r0.
       (e-tst '_retval)
       (e-write2 #+(or for-vax for-tahoe) 'jeql #+for-68k 'jeq beglab)
       (e-move '_lispretval (e-cvt 'reg))
       (e-write2 #+(or for-vax for-tahoe) 'jbr #+for-68k 'jra finlab)
       (e-label beglab)
       (d-exp (caddr v-form))
       (e-label finlab)
       (d-popframe)    ; remove catch frame from stack
       (unpush g-locs)    ; remove (catcherrset . 0)
       (unpush g-labs)  ; allow labels again
       (d-clearreg)))

;--- d-pushframe :: put an evaluation frame on the stack
;
; This is equivalant in the C system to 'errp = Pushframe(class,arg1,arg2);'
; We stack a frame which describes the class (will always be F_CATCH)
; and the other option args.
; 2/10/82 - it is a bad idea to stack a variable number of arguments, since
; this makes it more complicated to unstack frames.  Thus we will always
; stack the maximum --jkf
(defun d-pushframe (class arg1 arg2)
  (C-push (e-cvt arg2))
  (C-push (e-cvt arg1))
  (C-push `($ ,class))
  (if (null $global-reg$)
      then (e-move '#.np-reg '#.np-sym)
       (e-move '#.np-reg '#.lbot-sym))
  (e-quick-call '_qpushframe)
  (e-move (e-cvt 'reg) '_errp)
  (push '(catcherrset . 0) g-locs))

;--- d-popframe :: remove an evaluation frame from the stack
;
; This is equivalent in the C system to 'errp = Popframe();'
;  n is the number of arguments given to the pushframe which
; created this frame.  We have to totally remove this frame from
; the stack only if we are in a local function, but for now, we just
; do it all the time.
;
(defun d-popframe ()
   (let ((treg #+(or for-vax for-tahoe) 'r1 #+for-68k 'a5))
       (e-move '_errp treg)
       (e-move `(#.OF_olderrp ,treg) '_errp)
       ; there are always 3 arguments pushed, and the frame contains 5
       ; longwords.  We should make these parameters into manifest
       ; constants --jkf
       (e-add3 `($ ,(+ (* 3 4) (* 5 4))) treg 'sp)))

;--- c-cond :: compile a "cond" expression
;
; not that this version of cond is a 'c' rather than a 'cc' .
; this was done to make coding this routine easier and because
; it is believed that it wont harm things much if at all
;
(defun c-cond nil
  (makecomment '(beginning cond))
  (do ((clau (cdr v-form) (cdr clau))
       (finlab (d-genlab))
       (nxtlab)
       (save-reguse)
       (seent))
      ((or (null clau) seent)
       ; end of cond
       ; if haven't seen a t must store a nil in `reg'
       (if (null seent)  then (d-move 'Nil 'reg))
       (e-label finlab))

      ; case 1 - expr
      (if (atom (car clau))
      then (comp-err "bad cond clause " (car clau))
      ; case 2 - (expr)
       elseif (null (cdar clau))
      then (let ((g-loc (if (or g-cc g-loc) then 'reg))
             (g-cc (cons finlab nil))
             (g-ret (and g-ret (null (cdr clau)))))
            (d-exp (caar clau)))
      ; case 3 - (t expr1 expr2 ...)
       elseif (or (eq t (caar clau))
          (equal ''t (caar clau)))
      then (let ((g-loc (if (or g-cc g-loc) then 'reg))
             g-cc)
            (d-exps (cdar clau)))
           (setq seent t)
      ; case 4 - (expr1 expr2 ...)
       else (let ((g-loc nil)
          (g-cc (cons nil (setq nxtlab (d-genlab))))
          (g-ret nil))
         (d-exp (caar clau)))
        (setq save-reguse (copy g-reguse))
        (let ((g-loc (if (or g-cc g-loc) then 'reg))
          g-cc)
         (d-exps (cdar clau)))
        (if (or (cdr clau) (null seent)) then (e-goto finlab))
        (e-label nxtlab)
        (setq g-reguse save-reguse)))

  (d-clearreg))

;--- c-cons :: do a cons instruction quickly
;
(defun c-cons nil
  (d-pushargs (cdr v-form))        ; there better be 2 args
  (e-quick-call '_qcons)
  (setq g-locs (cddr g-locs))
  (setq g-loccnt (- g-loccnt 2))
  (d-clearreg))

;--- c-cxr :: compile a cxr instruction
;
;
(defun cc-cxr nil
  (d-supercxr t nil))

;--- d-supercxr :: do a general struture reference
;      type - one of fixnum-block,flonum-block,<other-symbol>
; the type is that of an array, so <other-symbol> could be t, nil
; or anything else, since anything except *-block is treated the same
;
; the form of a cxr is (cxr index hunk) but supercxr will handle
; arrays too, so hunk could be (getdata (getd 'arrayname))
;
; offsetonly is t if we only care about the offset of this element from
; the beginning of the data structure.  If offsetonly is t then type
; will be nil.
;
; Note: this takes care of g-loc and g-cc

#+(or for-vax for-tahoe)
(defun d-supercxr (type offsetonly)
  (let ((arg1 (cadr v-form))
    (arg2 (caddr v-form))
    lop rop semisimple)

       (if (fixp arg1) then (setq lop `(immed ,arg1))
       else (d-fixnumexp arg1)    ; calculate index into r5
        (setq lop 'r5))        ; and remember that it is there

       ; before we calculate the second expression, we may have to save
       ; the value just calculated into r5.  To be safe we stack away
       ; r5 if the expression is not simple or semisimple.
       (if (not (setq rop (d-simple arg2)))
       then (if (and (eq lop 'r5)
             (not (setq semisimple (d-semisimple arg2))))
            then (C-push (e-cvt lop)))
            (let ((g-loc 'reg) g-cc)
             (d-exp arg2))
            (setq rop 'r0)

        (if (and (eq lop 'r5) (not semisimple))
            then (C-pop (e-cvt lop))))

       (if (eq type 'flonum-block)
      then (setq lop (d-structgen lop rop 8))
           (e-write3 'movq lop 'r4)
           (e-quick-call '_qnewdoub)    ; box number
           (d-clearreg)            ; clobbers all regs
           (if (and g-loc (not (eq g-loc 'reg)))
          then (d-move 'reg g-loc))
           (if (car g-cc) then (e-goto (car g-cc)))
      else (setq lop (d-structgen lop rop 4)
             rop (if g-loc then
                 (if (eq type 'fixnum-block) then 'r5
                else (e-cvt g-loc))))
           (if rop
          then (if offsetonly
              then (e-write3 'moval lop rop)
              else (e-move lop rop))
               (if (eq type 'fixnum-block)
               then (e-call-qnewint)
                (d-clearreg)
                (if (not (eq g-loc 'reg))
                    then (d-move 'reg g-loc))
                ; result is always non nil.
                (if (car g-cc) then (e-goto (car g-cc)))
               else (d-handlecc))
        elseif g-cc
          then (if (eq type 'fixnum-block)
              then (if (car g-cc)
                  then (e-goto (car g-cc)))
              else (e-tst lop)
                (d-handlecc))))))

#+for-68k
(defun d-supercxr (type offsetonly)
   (let ((arg1 (cadr v-form))
     (arg2 (caddr v-form))
     lop rop semisimple)
       (makecomment `(Starting d-supercxr: vform: ,v-form))
       (if (fixp arg1) then (setq lop `(immed ,arg1))
       else (d-fixnumexp arg1)      ; calculate index into fixnum-reg
        (d-regused '#.fixnum-reg)
        (setq lop '#.fixnum-reg)) ; and remember that it is there
       ;
       ; before we calculate the second expression, we may have to save
       ; the value just calculated into fixnum-reg. To be safe we stack away
       ; fixnum-reg if the expression is not simple or semisimple.
       (if (not (setq rop (d-simple arg2)))
       then (if (and (eq lop '#.fixnum-reg)
             (not (setq semisimple (d-semisimple arg2))))
            then (C-push (e-cvt lop)))
        (let ((g-loc 'areg) g-cc)
            (d-exp arg2))
        (setq rop 'a0)
        ;
        (if (and (eq lop '#.fixnum-reg) (not semisimple))
            then (C-pop (e-cvt lop))))
       ;
       (if (eq type 'flonum-block)
       then (setq lop (d-structgen lop rop 8))
        (break " d-supercxr : flonum stuff not done.")
        (e-write3 'movq lop 'r4)
        (e-quick-call '_qnewdoub)    ; box number
        (d-clearreg)            ; clobbers all regs
        (if (and g-loc (not (eq g-loc 'areg)))
            then (d-move 'areg g-loc))
        (if (car g-cc) then (e-goto (car g-cc)))
       else (if (and (dtpr rop) (eq 'stack (car rop)))
            then (e-move (e-cvt rop) 'a1)
             (setq rop 'a1))
        (setq lop (d-structgen lop rop 4)
              rop (if g-loc then
                  (if (eq type 'fixnum-block)
                  then '#.fixnum-reg
                  else (e-cvt g-loc))))
        (if rop
            then (if offsetonly
                 then (e-write3 'lea lop 'a5)
                  (e-move 'a5 rop)
                 else (e-move lop rop))
             (if (eq type 'fixnum-block)
                 then (e-call-qnewint)
                  (d-clearreg)
                  (if (not (eq g-loc 'areg))
                      then (d-move 'areg g-loc))
                  ; result is always non nil.
                  (if (car g-cc) then (e-goto (car g-cc)))
                 else (e-cmpnil lop)
                  (d-handlecc))
         elseif g-cc
            then (if (eq type 'fixnum-block)
                 then (if (car g-cc)
                      then (e-goto (car g-cc)))
                 else (if g-cc
                      then (e-cmpnil lop)
                       (d-handlecc)))))
       (makecomment "Done with d-supercxr")))

;--- d-semisimple :: check if result is simple enough not to clobber r5
; currently we look for the case of (getdata (getd 'foo))
; since we know that this will only be references to r0.
; More knowledge can be added to this routine.
;
(defun d-semisimple (form)
  (or (d-simple form)
      (and (dtpr form)
       (eq 'getdata (car form))
       (dtpr (cadr form))
       (eq 'getd (caadr form))
       (dtpr (cadadr form))
       (eq 'quote (caadadr form)))))

;--- d-structgen :: generate appropriate address for indexed access
;    index - index address, must be (immed n) or r5 (which contains int)
;    base  - address of base
;    width - width of data element
; want to calculate appropriate address for base[index]
; may require emitting instructions to set up registers
; returns the address of the base[index] suitable for setting or reading
;
; the code sees the base as a stack value as a special case since it
; can generate (perhaps) better code for that case.

#+(or for-vax for-tahoe)
(defun d-structgen (index base width)
  (if (and (dtpr base) (eq (car base) 'stack))
      then (if (dtpr index)    ; i.e if index = (immed n)
           then (d-move index 'r5))    ; get immed in register
       ;  the result is always *n(r6)[r5]
       (append (e-cvt `(vstack ,(cadr base))) '(r5))
      else (if (not (atom base))    ; i.e if base is not register
           then (d-move base 'r0)    ; (if nil gets here we will fail)
            (d-clearreg 'r0)
            (setq base 'r0))
       (if (dtpr index) then `(,(* width (cadr index)) ;immed index
                    ,base)
                else `(0 ,base r5))))

#+for-68k
(defun d-structgen (index base width)
   (if (and (dtpr base) (eq (car base) 'stack))
       then (break "d-structgen: bad args(1)")
       else (if (not (atom base))    ; i.e if base is not register
        then (d-move base 'a0)    ; (if nil gets here we will fail)
             (d-clearreg 'a0)
             (setq base 'a0))
        (if (dtpr index)
        then `(,(* width (cadr index)) ,base)
        else (d-regused 'd6)
             (e-move index 'd6)
             (e-write3 'asll '($ 2) 'd6)
             `(% 0 ,base d6))))

;--- c-rplacx :: complile a rplacx expression
;
;  This simple calls the general structure hacking function, d-superrplacx
;  The argument, hunk, means that the elements stored in the hunk are not
;  fixum-block or flonum-block arrays.
(defun c-rplacx nil
  (d-superrplacx 'hunk))

;--- d-superrplacx :: handle general setting of things in structures
;    type - one of fixnum-block, flonum-block, hunk
; see d-supercxr for comments
; form of rplacx is (rplacx index hunk valuetostore)
#+(or for-vax for-tahoe)
(defun d-superrplacx (type)
     (let ((arg1 (cadr v-form))
           (arg2 (caddr v-form))
           (arg3 (cadddr v-form))
           lop rop semisimple)

          ; calulate index and put it in r5 if it is not an immediate
          ; set lop to the location of the index
          (if (fixp arg1) then (setq lop `(immed ,arg1))
          else (d-fixnumexp arg1)
               (setq lop 'r5))

          ; set rop to the location of the hunk.  If we have to
          ; calculate the hunk, we may have to save r5.
          ; If we are doing a rplacx (type equals hunk) then we must
          ; return the hunk in r0.
          (if (or (eq type 'hunk) (not (setq rop (d-simple arg2))))
          then (if (and (eq lop 'r5)
                (not (setq semisimple (d-semisimple arg2))))
               then (d-move lop '#.Cstack))
               (let ((g-loc 'r0) g-cc)
                (d-exp arg2))
               (setq rop 'r0)

               (if (and (eq lop 'r5) (not semisimple))
               then (d-move '#.unCstack lop)))

          ; now that the index and data block locations are known, we
          ; caclulate the location of the index'th element of hunk
          (setq rop
            (d-structgen lop rop
                 (if (eq type 'flonum-block) then 8 else 4)))

          ; the code to calculate the value to store and the actual
          ; storing depends on the type of data block we are storing in.
          (if (eq type 'flonum-block)
          then (if (setq lop (d-simple `(cdr ,arg3)))
               then (e-write3 'movq (e-cvt lop) rop)
               else ; preserve rop since it may be destroyed
                ; when arg3 is calculated
                (e-write3 'movaq rop '#.Cstack)
                (let ((g-loc 'r0) g-cc)
                     (d-exp arg3))
                (d-clearreg 'r0)
                (e-write3 'movq '(0 r0) "*(sp)+"))
           elseif (and (eq type 'fixnum-block)
               (setq arg3 `(cdr ,arg3))
               nil)
              ; fixnum-block is like hunk except we must grab the
              ; fixnum value out of its box, hence the (cdr arg3)
           thenret
           else (if (setq lop (d-simple arg3))
            then (e-move (e-cvt lop) rop)
            else ; if we are dealing with hunks, we must save
                 ; r0 since that contains the value we want to
                 ; return.
                 (if (eq type 'hunk) then (d-move 'reg 'stack)
                              (Push g-locs nil)
                              (incr g-loccnt))
                 (e-write3 'moval rop '#.Cstack)
                 (let ((g-loc "*(sp)+") g-cc)
                  (d-exp arg3))
                 (if (eq type 'hunk) then (d-move 'unstack 'reg)
                              (unpush g-locs)
                              (decr g-loccnt))
                 (d-clearreg 'r0)))))

#+for-68k
(defun d-superrplacx (type)
   (let ((arg1 (cadr v-form))
     (arg2 (caddr v-form))
     (arg3 (cadddr v-form))
     lop rop semisimple)
       (makecomment `(starting d-superrplacx ,type :: v-form = ,v-form))
       ;
       ; calulate index and put it in '#.fixnum-reg if it is not an immediate
       ; set lop to the location of the index
       (if (fixp arg1) then (setq lop `(immed ,arg1))
       else (d-fixnumexp arg1)
        (d-regused '#.fixnum-reg)
        (setq lop '#.fixnum-reg))
       ;
       ; set rop to the location of the hunk.  If we have to
       ; calculate the hunk, we may have to save '#.fixnum-reg.
       ; If we are doing a rplacx (type equals hunk) then we must
       ; return the hunk in d0.
       (if (or (eq type 'hunk) (not (setq rop (d-simple arg2))))
       then (if (and (eq lop '#.fixnum-reg)
             (not (setq semisimple (d-semisimple arg2))))
            then (d-move lop '#.Cstack))
        (let ((g-loc 'a0) g-cc)
            (d-exp arg2))
        (setq rop 'a0)
        (if (and (eq lop '#.fixnum-reg) (not semisimple))
            then (d-move '#.unCstack lop)))
       ;
       ; now that the index and data block locations are known, we
       ; caclulate the location of the index'th element of hunk
       (setq rop
         (d-structgen lop rop
              (if (eq type 'flonum-block) then 8 else 4)))
       ;
       ; the code to calculate the value to store and the actual
       ; storing depends on the type of data block we are storing in.
       (if (eq type 'flonum-block)
       then (break "flonum stuff not in yet")
        (if (setq lop (d-simple `(cdr ,arg3)))
            then (e-write3 'movq (e-cvt lop) rop)
            else ; preserve rop since it may be destroyed
             ; when arg3 is calculated
             (e-write3 'movaq rop '#.Cstack)
             (let ((g-loc 'd0) g-cc)
                 (d-exp arg3))
             (d-clearreg 'd0)
             (e-write3 'movq '(0 d0) "*(sp)+"))
    elseif (and (eq type 'fixnum-block)
            (setq arg3 `(cdr ,arg3))
            nil)
         ; fixnum-block is like hunk except we must grab the
         ; fixnum value out of its box, hence the (cdr arg3)
       thenret
       else (if (setq lop (d-simple arg3))
            then (e-move (e-cvt lop) rop)
            else ; if we are dealing with hunks, we must save
             ; d0 since that contains the value we want to
             ; return.
             (if (eq type 'hunk)
                 then (L-push 'a0)
                  (push nil g-locs)
                  (incr g-loccnt))
             (e-write3 'lea rop 'a5)
             (C-push 'a5)
             (let ((g-loc '(racc * 0 sp)) g-cc)
                 (d-exp arg3))
             (if (eq type 'hunk)
                 then (L-pop 'd0)
                  (unpush g-locs)
                  (decr g-loccnt))))
       (makecomment '(d-superrplacx done))))

;--- cc-cxxr :: compile a "c*r" instr where *
;        is any sequence of a's and d's
;    - arg : argument of the cxxr function
;    - pat : a list of a's and d's in the reverse order of that
;            which appeared between the c and r
;
#+(or for-vax for-tahoe)
(defun cc-cxxr (arg pat)
  (prog (resloc loc qloc sofar togo keeptrack)
    ; check for the special case of nil, since car's and cdr's
    ; are nil anyway
    (if (null arg)
        then (if g-loc then (d-move 'Nil g-loc)
             (d-handlecc)
          elseif (cdr g-cc) then (e-goto (cdr g-cc)))
         (return))

    (if (and (symbolp arg) (setq qloc (d-bestreg arg pat)))
        then (setq resloc (car qloc)
               loc   resloc
               sofar  (cadr qloc)
               togo   (caddr qloc))
        else (setq resloc
               (if (d-simple arg)
               thenret
               else (let ((g-loc 'reg)
                      (g-cc nil)
                      (g-ret nil))
                    (d-exp arg))
                'r0))
           (setq sofar nil togo pat))

    (if (and arg (symbolp arg)) then (setq keeptrack t))

       ; if resloc is a global variable, we must move it into a register
       ; right away to be able to do car's and cdr's
       (if (and (dtpr resloc) (or (eq (car resloc) 'bind)
                  (eq (car resloc) 'vstack)))
       then (d-move resloc 'reg)
        (setq resloc 'r0))

       ; now do car's and cdr's .  Values are placed in r0. We stop when
       ; we can get the result in one machine instruction.  At that point
       ; we see whether we want the value or just want to set the cc's.
       ; If the intermediate value is in a register,
       ; we can do : car cdr cddr cdar
       ; If the intermediate value is on the local vrbl stack or lbind
       ; we can do : cdr
       (do ((curp togo newp)
        (newp))
       ((null curp) (if g-loc then (d-movespec loc g-loc)
                elseif g-cc then (e-tst loc))
                    (d-handlecc))
       (if (symbolp resloc)
           then (if (eq 'd (car curp))
            then (if (or (null (cdr curp))
                     (eq 'a (cadr curp)))
                 then (setq newp (cdr curp)   ; cdr
                        loc `(0 ,resloc)
                        sofar (append sofar (list 'd)))
                 else (setq newp (cddr curp)  ; cddr
                        loc `(* 0 ,resloc)
                        sofar (append sofar
                              (list 'd 'd))))
            else (if (or (null (cdr curp))
                     (eq 'a (cadr curp)))
                 then (setq newp (cdr curp)   ; car
                        loc `(4 ,resloc)
                        sofar (append sofar (list 'a)))
                 else (setq newp (cddr curp)  ; cdar
                        loc `(* 4 ,resloc)
                        sofar (append sofar
                              (list 'a 'd)))))
           elseif (and (eq 'd (car curp))
               (not (eq '* (car (setq loc (e-cvt resloc))))))
         then (setq newp (cdr curp)    ; (cdr <local>)
                loc (cons '* loc)
                sofar (append sofar (list 'd)))
           else  (setq loc (e-cvt resloc)
               newp curp))
       (if newp            ; if this is not the last move
           then (setq resloc
              (d-allocreg (if keeptrack then nil else 'r0)))
            (d-movespec loc resloc)
            (if keeptrack then (d-inreg resloc (cons arg sofar)))))))

#+for-68k
(defun cc-cxxr (arg pat)
   (prog (resloc loc qloc sofar togo keeptrack)
       (makecomment '(starting cc-cxxr))
       ; check for the special case of nil, since car's and cdr's
       ; are nil anyway
       (if (null arg)
       then (if g-loc then (d-move 'Nil g-loc))
        (if (cdr g-cc) then (e-goto (cdr g-cc)))
        (return))
       (if (and (symbolp arg) (setq qloc (d-bestreg arg pat)))
       then (setq resloc (car qloc)
              loc   resloc
              sofar  (cadr qloc)
              togo   (caddr qloc))
       else (setq resloc
              (if (d-simple arg) thenret
              else (d-clearreg 'a0)
                   (let ((g-loc 'areg)
                     (g-cc nil)
                     (g-ret nil))
                   (d-exp arg))
                   'a0))
        (setq sofar nil togo  pat))
       (if (and arg (symbolp arg)) then (setq keeptrack t))
       ;
       ; if resloc is a global variable, we must move it into a register
       ; right away to be able to do car's and cdr's
       (if (and (dtpr resloc) (or (eq (car resloc) 'bind)
                  (eq (car resloc) 'vstack)))
       then (d-move resloc 'areg)
        (setq resloc 'a0))
       ; now do car's and cdr's .  Values are placed in a0. We stop when
       ; we can get the result in one machine instruction.  At that point
       ; we see whether we want the value or just want to set the cc's.
       ; If the intermediate value is in a register,
       ; we can do : car cdr cddr cdar
       ; If the intermediate value is on the local vrbl stack or lbind
       ; we can do : cdr
       (do ((curp togo newp)
        (newp))
       ((null curp)
        (if g-loc then (d-movespec loc g-loc))
        ;
        ;;;important: the below kludge is needed!!
        ;;;consider the compilation of the following:
        ;
        ;;; (cond ((setq c (cdr c)) ...))
        ;;; the following instructions are generated:
        ;;; movl  a4@(N),a5    ; the setq
        ;;; movl  a5@,a4@(N)
        ;;; movl  a4@,a5       ; the last two are generated if g-cc
        ;;; cmpl  a5@,d7       ; is non-nil
        ;
        ;;; observe that the original value the is supposed to set
        ;;; the cc's is clobered in the operation!!
        ;(msg "g-loc: " (e-cvt g-loc) N "loc: " loc N)
        (if g-cc
        then (if (and (eq '* (car loc))
                  (equal (caddr loc) (cadr (e-cvt g-loc))))
             then (e-cmpnil '(0 a5))
             else (e-cmpnil loc)))
        (d-handlecc))
       (if (symbolp resloc)
           then (if (eq 'd (car curp))
            then (if (or (null (cdr curp))
                     (eq 'a (cadr curp)))
                 then (setq newp (cdr curp)   ; cdr
                        loc `(0 ,resloc)
                        sofar (append sofar (list 'd)))
                 else (setq newp (cddr curp)  ; cddr
                        loc `(* 0 ,resloc)
                        sofar (append sofar
                              (list 'd 'd))))
            else (if (or (null (cdr curp))
                     (eq 'a (cadr curp)))
                 then (setq newp (cdr curp)   ; car
                        loc `(4 ,resloc)
                        sofar (append sofar (list 'a)))
                 else (setq newp (cddr curp)  ; cdar
                        loc `(* 4 ,resloc)
                        sofar (append sofar
                              (list 'a 'd)))))
        elseif (and (eq 'd (car curp))
            (not (eq '* (car (setq loc (e-cvt resloc))))))
           then (setq newp (cdr curp)    ; (cdr <local>)
              loc (cons '* loc)
              sofar (append sofar (list 'd)))
           else  (setq loc (e-cvt resloc)
               newp curp))
       (if newp            ; if this is not the last move
           then (setq resloc
              (d-alloc-register 'a
                        (if keeptrack then nil else 'a1)))
            (d-movespec loc resloc)
            ;(if keeptrack then (d-inreg resloc (cons arg sofar)))
            ))
       (makecomment '(done with cc-cxxr))))