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/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

/* 80x86/weights.c */

/**********************************************************************

$Author: release $

$Date: 1998/01/17 15:55:52 $

$Revision: 1.1.1.1 $

$Log: weights.c,v $

 * Revision 1.1.1.1  1998/01/17  15:55:52  release

 * First version to be checked into rolling release.

 *

 * Revision 1.14  1997/10/10  18:25:40  pwe

 * prep ANDF-DE revision

 *

 * Revision 1.13  1996/11/08  16:19:22  pwe

 * check_stack to check before modifying stack

 *

 * Revision 1.12  1996/05/20  14:30:45  pwe

 * improved 64-bit handling

 *

 * Revision 1.11  1996/05/13  12:52:10  pwe

 * undo premature commit

 *

 * Revision 1.9  1996/01/22  14:31:13  pwe

 * PIC const*const, contop top_tag & linux 64-bit ints

 *

 * Revision 1.8  1996/01/17  11:24:42  pwe

 * resurrect performance

 *

 * Revision 1.7  1995/09/05  16:25:14  pwe

 * specials and exception changes

 *

 * Revision 1.6  1995/08/04  08:29:56  pwe

 * 4.0 general procs implemented

 *

 * Revision 1.5  1995/05/05  12:47:32  pwe

 * missing bracket

 *

 * Revision 1.4  1995/05/02  13:27:42  pwe

 * strengthen test for no side effect

 *

 * Revision 1.3  1995/03/23  13:25:39  pwe

 * limit scale in deeply nested repeats

 *

 * Revision 1.2  1995/01/30  12:56:59  pwe

 * Ownership -> PWE, tidy banners

 *

 * Revision 1.1  1994/10/27  14:15:22  jmf

 * Initial revision

 *

 * Revision 1.1  1994/07/12  14:43:24  jmf

 * Initial revision

 *

**********************************************************************/

#include "config.h"

#include <limits.h>

#include "common_types.h"

#include "expmacs.h"

#include "tags.h"

#include "exp.h"

#include "shapemacs.h"

#include "basicread.h"

#include "flags.h"

#include "localflags.h"

#include "coder.h"

#include "weights.h"

/* MACROS */

#define max(x,y) ((x>=y) ? (x) : (y))

#define wno 6

 /* number of available registers */

#define wfno 7

 /* number of available floating point registers */

/* IDENTITIES */

float  vzeros[wno + wfno] = {

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

float  vmoveregs[wno + wfno] = {	/* for the move instruction */

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

float  vcmpregs[wno + wfno] = {	/* for the cmp instruction */

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

float  vdivregs[wno + wfno] = {	/* for the div instruction */

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

float  vapplyregs[wno + wfno] = {/* for apply */

  0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

};

struct wt {

  float  w_weights[wno + wfno];

  int  booked;

  int  flbooked;

};

typedef struct wt   weights;

				/* weights[i] is the value of putting a

				   declaration in a register if there are

				   i registers available. */

struct wpt {

  weights wp_weights;

  int  wp_break;		/* break is the number of registers that

				   must be available at this point for it

				   to be worthwhile putting this value in

				   a register */

};

typedef struct wpt  wp;

struct elt {

  exp wident;

  struct elt *etl;

};

typedef struct elt  explist;

				/* list of identity declarations in force

				   at this point */

weights weightsv PROTO_S ( ( exp, explist * ) ) ;

/* VARIABLES */

weights zeros, moveregs, cmpregs, divregs, applyregs;

	/* init by init_weights */

/* PROCEDURES */

static int no_side_aux

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

  exp arg;

  if (name(e)==name_tag || name(e)==env_offset_tag || name(e)==top_tag || son(e)==nilexp)

    return 1;

  for (arg=son(e); ; arg=bro(arg))

  {

    if ((!is_a(name(arg)) && name(arg) != ident_tag) || !no_side_aux(arg))

      return 0;

    if (last(arg))

      return 1;

  }

}

/* test for guaranteed no side effect */

/* simple assignment is permitted */

int no_side

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

  return ((is_a (name (e)) || name (e) == test_tag || name (e) == ass_tag ||

	   name (e) == testbit_tag || name (e) == ident_tag)

	&& no_side_aux (e));

}

/* add two weight vectors */

weights add_weights

    PROTO_N ( (w1, w2) )

    PROTO_T ( weights w1 X weights w2 )

{

  weights r;

  float  wa,

         wb;

  int i;

  for (i = 0; i < (wno + wfno); ++i) {

    wa = (w1.w_weights)[i];

    wb = (w2.w_weights)[i];

    (r.w_weights)[i] = wa + wb;

  };

  r.booked = max (w1.booked, w2.booked);

  r.flbooked = max (w1.flbooked, w2.flbooked);

  return (r);

}

void init_weights

    PROTO_Z ()

{

		/* initialisation of constants */

  int  i;

  for (i = 0; i < (wno + wfno); ++i) {

    (zeros.w_weights)[i] = vzeros[i];

    (moveregs.w_weights)[i] = vmoveregs[i];

    (cmpregs.w_weights)[i] = vcmpregs[i];

    (divregs.w_weights)[i] = vdivregs[i];

    (applyregs.w_weights)[i] = vapplyregs[i];

  };

  zeros.booked = -1;

  moveregs.booked = 1;

  cmpregs.booked = 1;

  divregs.booked = 1;

  applyregs.booked = 1;

  zeros.flbooked = -1;

  moveregs.flbooked = -1;

  cmpregs.flbooked = -1;

  divregs.flbooked = -1;

  applyregs.flbooked = 2;

  return;

}

void markcall

    PROTO_N ( (el) )

    PROTO_T ( explist * el )

{

  explist * t = el;

  while (t != (explist *) 0) {

    set_intnl_call (t -> wident);

    t = t -> etl;

  };

}

/* mark all the declarations in the list

   of currently active declarations, to

   show that there is a call, movc3 etc.

   within their scope */

void markmove

    PROTO_N ( (el) )

    PROTO_T ( explist * el )

{

  explist * t = el;

  while (t != (explist *) 0) {

    set_intnl_call (t -> wident);

    t = t -> etl;

  };

}

/* mark to show reg1 may be needed */

void markreg1

    PROTO_N ( (el) )

    PROTO_T ( explist * el )

{

  explist * t = el;

  while (t != (explist *) 0) {

    set_intnl_call (t -> wident);

    t = t -> etl;

  };

}

/* work out weights for a declaration and

   set up the break point to put in the no

   field of the declaration */

wp max_weights

    PROTO_N ( (size, locp, ws, isfl) )

    PROTO_T ( int size X float locp X weights ws X int isfl )

{

  int  k = (size + 31) / 32;

  int  bk = 11;

  int bkset = 0;

  int  q;

  int  i;

  float * w = &(ws.w_weights)[(isfl) ? wno : 0];

  wp res;

  float *pw = &((res.wp_weights).w_weights)[(isfl) ? wno : 0];

  int  bkd = (isfl) ? ws.flbooked : ws.booked;

  int  lwno = (isfl) ? wfno : wno;

  res.wp_weights.booked = ws.booked;

  res.wp_weights.flbooked = ws.flbooked;

  for (i = 0; i < (wno + wfno); ++i)

    ((res.wp_weights).w_weights)[i] = (ws.w_weights)[i];

   {

    float  loc = locp * k;

    q = -1;

    for (i = 0; i < lwno; ++i) {

      {

	if (i < (k + q))

	  pw[i] = w[i];

	else {

	  if (i == (k + q)) {

	    if (loc >= w[i] && bkd <= q) {

	      pw[i] = loc;

	      bk = i + 1;

	      bkset = 1;

	    }

	    else

	      pw[i] = w[i];

	  }

	  else {

	    if ((loc + w[i - k]) >= w[i]) {

	      pw[i] = loc + w[i - k];

	      if (!bkset) {

		bk = i + 1;

		bkset = 1;

	      };

	    }

	    else

	      pw[i] = w[i];

	  };

	};

      };

    };

  };

  res.wp_break = bk;

  return (res);

}

/* see if we must use movc3?? */

weights try_mc3

    PROTO_N ( (e, ws, el) )

    PROTO_T ( exp e X weights ws X explist * el )

{

  int  sz = shape_size(sh(e));

  if (sz <= 128)

    return (ws);

  markmove (el);

  return (add_weights (ws, moveregs));

}

/* work out the weights for a list of exp.

   usemc3 is 1 if movc3 may be used. */

weights add_wlist

    PROTO_N ( (re, usemc3, el) )

    PROTO_T ( exp re X int usemc3 X explist * el )

{

  weights wl1, wl2;

  if (re == nilexp)

    return (zeros);

  wl1 = weightsv (re, el);

  if (usemc3)

    wl1 = try_mc3 (re, wl1, el);

  while (!last (re)) {

    re = bro (re);

    wl2 = weightsv (re, el);

    if (usemc3)

      wl1 = add_weights (wl1, try_mc3 (re, wl2, el));

    else

      wl1 = add_weights (wl1, wl2);

  };

  return (wl1);

}

/* can the value defined by e be put in a register */

int regable

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

  unsigned char  n;

  shape sha = sh (son (e));

  n = name (sha);

  if (isvis (e) || n == cpdhd || n == nofhd || n == s64hd || n == u64hd)

    return (0);

  if (all_variables_visible && isvar(e))

    return 0;

  return (1);

}

int isflsh

    PROTO_N ( (s) )

    PROTO_T ( shape s )

{

  unsigned char  n = name (s);

  return (n >= shrealhd && n <= doublehd);

}

/* Work out weights and set break points

   scale is the expected number of times

   that this operation will be done.

   During the scan the expected number of

   times use is made of something declared

   is computed in the no of the

   declaration. After the scan the break

   point is put into the no of the

   declaration */

weights weightsv

    PROTO_N ( (e, el) )

    PROTO_T ( exp e X explist * el )

{

  unsigned char  n = name (e);

  float old_scale;

  weights swl, bwl;

  switch (n) {

    case name_tag: {

	if (!isglob (son (e)))

	  fno (son (e)) += scale;/* add number of uses to the no field of

				   the declaration */

	return (zeros);

      };

    case make_lv_tag:

        return zeros;

    case ident_tag:

       {

	explist nel;

	exp t = pt (e);

	nel.wident = e;

	nel.etl = el;

	while (isvar (e) && !isvis (e) && t != nilexp) {

	  if (!(last (t) && name (bro (t)) == cont_tag) &&

              !(last(t) && name(bro(t)) == hold_tag) &&

	      !(last (bro (t)) && (name (bro (bro (t))) == ass_tag ||

		  name (bro (bro (t))) == assvol_tag

		)))

	    setvis (e);

	  t = pt (t);

	};

	if (son (e) != nilexp) {

	  weights wdef, wbody;

	  exp def = son (e);

	  exp body = bro (def);

	  if (name(sh(def)) == u64hd || name(sh(def)) == s64hd)

	    markreg1(el);

	  fno (e) = 0.0;	/* clear the accumulated value field */

	  wbody = weightsv (body, &nel);

	  /* do body (which will add to the accumulated value field */

	  if (regable (e)) {

	    wp p;

	    float  loc = fno (e);

            if (has_intnl_call(e))

               loc += 2.0;

	    p = max_weights (shape_size(sh (def)),

		(name (def) == name_tag && isusereg (e)) ? 1.0 : loc,

		wbody,

		isflsh (sh (def)));

	    if (name (def) == clear_tag)

	      wdef = zeros;

	    else {

	      float  sp_scale = scale;

	      if (!isvar (e) &&

		  ((name (def) == name_tag && !isvar (son (def)) &&

		      (!isglob (son (def))) && !isloadparam(def)

		    ) ||

		    (name (def) == cont_tag &&

		      name (son (def)) == name_tag &&

		      isvar (son (son (def))) &&

		      (!isglob (son (son (def)))) &&

		      no_side (body)))) {

		if (isusereg (e)) {

		  sp_scale = 8.0 * fno (e);

		}

		else

		  sp_scale = fno (e);

		p.wp_break = 0;

		p.wp_weights = wbody;

	      };

              old_scale = scale;

              scale = sp_scale;

	      wdef =

		weightsv (def, el);

	      wdef = try_mc3 (def, wdef, el);

              scale = old_scale;

	    };

	    no (e) = p.wp_break;/* set the break point */

	    return (add_weights (wdef, p.wp_weights));

	  };

	  if (name(sh(def)) == nofhd && ptno(sh(def)) == realhd &&

		shape_size(sh(def)) >= 640)

	    useful_double = 1;

	  if (name (def) == clear_tag)

	    wdef = zeros;

	  else {

	    wdef =

		weightsv (def, el);

	      wdef = try_mc3 (def, wdef, el);

	  };

	  no (e) = 16;

	  return (add_weights (wdef, wbody));

	};

	return (zeros);

      };

    case labst_tag: {

	explist nel;

	weights wbody;

	nel.wident = e;

	nel.etl = el;

	old_scale = scale;

	wbody = weightsv (bro (son (e)), &nel);

	scale = old_scale;

	return (wbody);

      };

    case rep_tag: {

	swl = weightsv (son (e), el);

        old_scale = scale;

        if (scale < 1e30)

		scale = 20*scale;

	bwl = weightsv (bro (son (e)), el);

        scale = old_scale;

	return (add_weights (swl, bwl));

      };

    case cond_tag:  {

        old_scale = scale;

        scale = 0.5*scale;

        swl = weightsv (son (e), el);

	bwl = weightsv (bro (son (e)), el);

        scale = old_scale;

	return (add_weights (swl, bwl));

      };

    case case_tag:

      return (weightsv (son (e), el));

    case compound_tag:

      return (add_wlist (son (e), 1, el));

      /* may use movc3 for component */

    case res_tag:

    case untidy_return_tag:

      return (weightsv (son (e), el));

    case asm_tag:

    case apply_tag:

    case apply_general_tag:

    case tail_call_tag:

      {

        if (name(sh(e)) != bothd && !builtinproc(e))

	  markcall (el);

	return (add_weights (add_wlist (son (e), 0, el),

	      applyregs));

      };

    case ass_tag:

    case assvol_tag: {

      /* may use movc3 for assigned value */

      unsigned char shn = name (sh (bro (son (e))));

      weights temp;

      temp = weightsv (bro (son (e)), el);

      if (shn == u64hd || shn == s64hd)

	markreg1 (el);

      return (add_weights (weightsv (son (e), el),

	    try_mc3 (bro (son (e)), temp, el)

	  )

	);

      };

    case proc_tag:

    case general_proc_tag: {

	IGNORE weightsv (son (e), (explist *) 0);

	return (zeros);

      };

    case movecont_tag:

      if (isnooverlap(e))

        return (add_weights (add_wlist (son (e), 0, el), moveregs));

      else {

        markcall(el);

        return (add_wlist (son (e), 0, el));

      };

    case val_tag:

    case real_tag:

    case env_offset_tag:

      return (zeros);

    case test_tag:

     {weights wlarg;

      if (name(sh(son(e))) == s64hd || name(sh(son(e))) == u64hd)

	markreg1 (el);				/* use of reg0 can include reg1 */

      wlarg = add_wlist (son (e), 0, el);

      return (wlarg);

     };

    case prof_tag:

      scale = no(e);

      return zeros;

    case alloca_tag:

     {if (checkalloc(e))

	markreg1 (el);

      return (add_wlist (son (e), 0, el));

     };

    default:

      if (sh(e) != nilexp &&

		(name(sh(e)) == s64hd || name(sh(e)) == u64hd))

	markreg1 (el);				/* use of reg0 can include reg1 */

      return (add_wlist (son (e), 1, el));

  };

}

void comp_weights

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

  scale = 1.0;

  IGNORE weightsv (e, (explist *) 0);

  return;

}