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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.

*/

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

$Author: release $

$Date: 1998/01/17 15:56:05 $

$Revision: 1.1.1.1 $

$Log: code_here.c,v $

 * Revision 1.1.1.1  1998/01/17  15:56:05  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1995/08/16  16:06:31  currie

 * Shortened some .h names

 *

 * Revision 1.1  1995/04/13  09:08:06  currie

 * Initial revision

 *

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

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

		code_here

This contains procedures :-

regofval, fregofval : to see if an exp is a load_tag that has been allocated to a register.

regoperand, freoperand : to evaluate an exp into a register using make_code

code_here :  calls make_code and ensures that any internal exit labels are tied up after the call

	The procedures regoperand and fregoperand evaluate their

exp parameter into a single register using make_code. This register is

returned. An initial test with regofval checks to see if the exp is already

in a register.

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

#include "config.h"

#include "common_types.h"

#include "addrtypes.h"

#include "procrectypes.h"

#include "labels.h"

#include "expmacs.h"

#include "tags.h"

#include "new_code.h"

#include "exp.h"

#include "bitsmacs.h"

#include "locate.h"

#include "regexps.h"

#include "inst_fmt.h"

#include "mips_ins.h"

#include "shapemacs.h"

#include "special.h"

#include "handle_sregs.h"

#include "code_here.h"

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

regofval

The procedure regofval checks to see if an exp is a load_tag

that has been allocated into a fixpnt register and if so return it or else 100.

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

int   regofval

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

        exp decx = son (e);

  if (name (e) == name_tag && name (decx) == ident_tag) {/* ident tag */

    if ((props (decx) & defer_bit) != 0) {

      return regofval (son (decx));

    }

    if ((props (decx) & inreg_bits) != 0) {

      return ((isvar (decx)) ? (-no (decx)) : (no (decx)));

    }

    return 100;

  }

  else

  if ((name (e) == val_tag && no (e) == 0) ||

		 name(e) == clear_tag || name(e)== top_tag) {

	return 0;

  }

  else {

	return 100;

  }

}

int   fregofval

    PROTO_N ( (e) )

    PROTO_T ( exp e )

{

        exp decx = son (e);

  if (name (e) == name_tag && name (decx) == ident_tag) {

    if ((props (decx) & infreg_bits) != 0) {

      return no (decx);

    }

    return 100;

  }

  else

  if (name(e)==clear_tag || name(e)==top_tag) {

	return 0;

  }

  else {

      return 100;

  }

}

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

code_here

The procedure code_here calls make_code and ensures that

any internal exit labels are tied up after the call.

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

int   code_here

    PROTO_N ( (e, sp, dest) )

    PROTO_T ( exp e X space sp X where dest )

{

        makeans mka;

  mka = make_code (e, sp, dest, 0);

  if (mka.lab != 0) {

    set_label (mka.lab);

  }

  return mka.regmove;

}

ash ash0 = {

  0, 0

};

ash ash32 = {

  32, 32

};

int   reg_operand

    PROTO_N ( (e, sp) )

    PROTO_T ( exp e X space sp )

{

  int   x = regofval (e);

  ans aa;

  where w;

  if (x >= 0 && x < 100) {

    return x;

  }				/* x is a register for e */

  if (name (e) == cont_tag) {

    x = regofval (son (e));

    if (x < 0) {

      return (-x);

    }

  }

  else

    if (name (e) == apply_tag && specialfn (son (e)) == 0) {

				/* apply proc */

      setregalt (aa, 0);

      w.answhere = aa;

      w.ashwhere = ash0;

      make_code (e, sp, w, 0);

      return 2;			/* simple proc calls give result in reg 2

				*/

    }

  aa = iskept (e);

  if (aa.discrim == inreg && regalt (aa) != 0) {

				/* the same expression has already been

				   evaluated into a reg */

    return regalt (aa);

  }

  if (aa.discrim == notinreg) {

    instore is;

    is = insalt (aa);

    if (is.adval && is.b.offset == 0) {

      int   r = is.b.base;

      /* the same expression has already been evaluated into a reg */

      return r;

    }

  }

  {

    int   reg = -1;

    setsomeregalt (aa, &reg);

    /* allow code_here to evaluate e into reg of its choice */

    w.answhere = aa;

    w.ashwhere = ashof (sh (e));

    code_here (e, sp, w);

    keepreg (e, reg);

    return reg;

  }

}

int   freg_operand

    PROTO_N ( (e, sp) )

    PROTO_T ( exp e X space sp )

{

  int   x = fregofval (e);

  ans aa;

  where w;

  freg fr;

  w.ashwhere = ashof (sh (e));

  if (x >= 0 && x < 100) {

    return x;

  }

  if (name (e) == cont_tag) {

    x = fregofval (son (e));

    if (x < 100) {

      return (x);

    }

  }

  else

    if (name (e) == apply_tag) {

      setregalt (aa, 0);

      w.answhere = aa;

      w.ashwhere = ash0;

      make_code (e, sp, w, 0);

      return 0;

    }

  aa = iskept (e);

  if (aa.discrim == infreg) {	/* e already evaluated in fl reg */

    return regalt (aa) /* cheat */ ;

  }

 { int reg = -1;

   somefreg sfr;

   sfr.fr = ®

   sfr.dble = fr.dble = (w.ashwhere.ashsize == 64) ? 1 : 0;

  setsomefregalt (aa, sfr);

  w.answhere = aa;

  /* evaluate e into reg ... */

  code_here (e, sp, w);

  fr.fr = reg;

  setfregalt(aa, fr);

  keepexp (e, aa);

  return reg;

 }

}