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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.

*/

/* 	$Id: locate.c,v 1.1.1.1 1998/01/17 15:56:00 release Exp $	 */

#ifndef lint

static char vcid[] = "$Id: locate.c,v 1.1.1.1 1998/01/17 15:56:00 release Exp $";

#endif /* lint */

/* 

   locate.c

   This file provides functions to locate an exp.

*/

/*

$Log: locate.c,v $

 * Revision 1.1.1.1  1998/01/17  15:56:00  release

 * First version to be checked into rolling release.

 *

 * Revision 1.4  1995/08/21  08:45:04  john

 * Changed include files

 *

 * Revision 1.3  1995/07/27  10:09:06  john

 * Modified due to change in general proc handling

 *

 * Revision 1.2  1995/05/16  10:53:23  john

 * Changes for spec 3.1

 *

 * Revision 1.1.1.1  1995/03/23  10:39:12  john

 * Entered into CVS

 *

 * Revision 1.9  1995/03/23  10:21:00  john

 * Changes for bitfields & offsets

 *

 * Revision 1.8  1995/01/26  13:43:16  john

 * Removed some unused variables

 *

*/

#include "config.h"

#include "addresstypes.h"

#include "expmacs.h"

#include "tags.h"

#include "inst_fmt.h"

#include "alpha_ins.h"

#include "bitsmacs.h"

#include "exp.h"

#include "procrecs.h"

#include "guard.h"

#include "eval.h"

#include "regexps.h"

#include "shapemacs.h"

#include "pseudo.h"

#include "getregs.h"

#include "move.h"

#include "handle_sregs.h"

#include "common_types.h"

#include "frames.h"

#include "code_here.h"

#include "reg_defs.h"

#include "locate.h"

#include "fail.h"

extern  FILE * as_file;

int locals_offset; /* the offset in bits of start of current locals */

int frame_size;	/* the size of the current stack frame in bits */

baseoff boff

    PROTO_N ( ( id ) )

    PROTO_T ( exp id )

{

  baseoff an;

  if (isglob (id)) {		/* globals */

    dec * gl = brog(id);

    long sno = gl->dec_u.dec_val.sym_number;

    an.base = -(sno + 1);

    an.offset = 0;

  }

  else {

    int   x = no (id);

    int   b = x & 0x3f;

    if(name(son(id)) == caller_name_tag){

      an.base = SP;

      an.offset = (x-b)>>4;

    }

    else if (b == SP) {

      an.base = SP;

      an.offset = ((x - b) >> 4) + (locals_offset >> 3);

      /* locally declared things accessed by sp*/

    }

    else if (b==FP && Has_fp) {

      an.base = FP;

      an.offset = ((x - b) >> 4)+((locals_offset-callee_size-frame_size)>>3);

      /* locally declared things accessed by fp */

    }    	

    else if((b == local_reg && Has_vcallees)){

      an.base = b;

      an.offset = (((x-b))>>4)+ ((locals_offset-frame_size/*-callee_size*/)>>3);

    }

    else if (b <= 31) {

	an.base = b;

	an.offset = ((x - b) >> 4);

	/* other base offsets */

    }

    else if (b == 32) {

      an.base = -((x - b) >> 6);

      an.offset = 0;

	  /* global names  */

    }

    else if (b == 33) {

      an.base = (x - b) >> 6;

      an.offset = 0;

      /* global anonymous */

    }

    else {

      failer ("not a baseoff in boff ");

    }

  }

  return an;

}

 /* 

    locate differs from locate1 only in that it looks to 

    see if e has already been evaluated somehow 

*/

where locate PROTO_S ((exp e, space sp, shape s, int dreg));

where locate1

    PROTO_N ( ( e, sp, s, dreg ) )

    PROTO_T ( exp e X space sp X shape s X int dreg )

{

  /* finds the address of e using shape s;

     sp gives available t-regs for any inner

     evaluation. dreg is historical (carried over from mipstrans). */

  ash a;

  ans aa;

  where wans;

  source src;

  a = ashof (s);

  switch (name (e)) {

   case name_tag: 

    {

      exp decx = son (e);

      bool var = isvar (decx);

      /* this a locally declared name ... */

      if (props (decx) & defer_bit) {

	/* ... it has been identified with a

	   simple expression which is better

	   evaluated every time */

	where w;

	w = locate (son (decx), sp, sh (son (decx)), dreg);

	if (no (e) == 0) {

	  aa = w.answhere;

	}

	else {

	  instore is;

	  switch (w.answhere.discrim) {

	    case notinreg: {

	      is = insalt (w.answhere);

	      is.b.offset += (no (e) / 8);

	      break;

	    }

	    default: 

	    failer ("NOT deferable");

	  }

	  setinsalt (aa, is);

	}

      }

      else if (props (decx) & inreg_bits) {

	/* ... it has been allocated in a fixed

	   point reg */

	if (var) {

	  setregalt (aa, no (decx));

	}

	else {

	  instore b;

	  b.b.base = no (decx);

	  b.b.offset = 0;

	  b.adval = 1;

	  setinsalt (aa, b);

	}

      }

      else if (props (decx) & infreg_bits) {

	/* ... it has been allocated in a floating

	   point reg */

	freg fr;

	fr.fr = no (decx);

	if(a.ashsize==64) 

	  fr.type = IEEE_double;

	else

	  fr.type = IEEE_single;

	setfregalt (aa, fr);

      }

      else {		/* ... it is in memory */

	instore is;

	if (var || (name (sh (e)) == prokhd &&

		    (son (decx) == nilexp || name (son (decx)) == proc_tag

		     || name(son(decx)) == general_proc_tag))) {

	  is.adval = 1;

	}

	else {

	  is.adval = 0;

	}

	is.b = boff (decx);

	is.b.offset += (no (e) / 8);

	setinsalt (aa, is);

      }

      wans.answhere = aa;

      wans.ashwhere = a;

      return wans;

    }

    case addptr_tag: 

    {

      exp sum = son (e);

      where wsum;

      int   addend;

      space nsp;

      int   reg;

      int   ind;

      instore is;

      ans asum;

      int multiplier;

      wsum = locate (sum, sp, sh (sum), NO_REG);

      asum = wsum.answhere;

      /* answer is going to be wsum displaced by integer result of

	   evaluating bro(sum) */

      switch (asum.discrim) {

      case notinreg: 

      {

	instruction scale_ins;

	is = insalt (asum);

	if (is.adval) {	/* wsum is a literal address in store ... 

			 */

	  baseoff b;

	  b = is.b;

	  if (b.base < 0 || b.base > 31) {

	    /* ... it is not a base-offset , so make

	       it one */

	    reg = getreg (sp.fixed);

	    load_store (i_lda, reg, b);

	    keepreg (sum, reg);

	    b.base = reg;

	    b.offset = 0;

	  }

	  nsp = guardreg (b.base, sp);

	  /* choose the appropriate instruction based on the 

	     multiplier.  Not shure if this is any faster than

	     using two instructions : mult & add.

	     */

	  if(name(bro(sum)) == offset_mult_tag){

	    multiplier = no(bro(son(bro(sum))));

	    switch(multiplier){

	    case 4:

	      scale_ins=i_s4addq;

	      addend = reg_operand(son(bro(sum)),nsp);

	      break;

	    case 8:

	      scale_ins=i_s8addq;

	      addend = reg_operand(son(bro(sum)),nsp);

	      break;

	    default:

	      scale_ins=i_addq;

	      addend = reg_operand(bro(sum),nsp);

	    }

	  }

	  else{

	    scale_ins=i_addq;

	    addend = reg_operand (bro (sum), nsp);

	  }

	  /* evaluate the displacement ... */

	  if (dreg == NO_REG)

	    dreg = getreg (nsp.fixed);

	  src.reg=0;

	  src.value=addend;

	  operate_fmt(scale_ins,src.value,b.base,dreg);

	  /* ... add it to the base register into new reg */

	  b.base = dreg;

	  is.b = b;

	  setinsalt (aa, is);

	  wans.answhere = aa;

	  wans.ashwhere = a;

	  /* ...and use it as base a literal base-offset result */

	  keepexp (e, aa);

	  return wans;

	}

	else {		/* wsum represents an actual pointer in

			   store... */

	  ind = getreg (sp.fixed);

	  load_store(i_ldq,ind,is.b);

	  /* ... so load it into a good register */

	}

	goto breakpt;

	/* should be break - thought there was cc error */

      }			/* end notinreg */

      case inreg: 

	/* wsum is already in reg */

      {

	ind = regalt (asum);

	goto breakpt;

      }

      default: {

	failer ("Locate ? reg");

      }

      }			/* end case */

    breakpt: 		/* register ind contains the evaluation of

		        1st operand of addptr */

      nsp = guardreg (ind, sp);

      if (name(bro(sum)) == env_offset_tag || 

	  name(bro(sum))==general_env_offset_tag) {

	is.b.base = ind;

	is.b.offset = frame_offset(son(bro(sum)));

      } 

      else {

	instruction ins=i_addq;

	if(name(bro(sum)) == offset_mult_tag && 

	   name(bro(son(bro(sum))))==val_tag){

	  switch(no(bro(son(bro(sum))))){

	  case 4:

	    ins=i_s4addq;

	    addend = reg_operand(son(bro(sum)),nsp);

	    break;

	  case 8:

	    ins=i_s8addq;

	    addend = reg_operand(son(bro(sum)),nsp);

	    break;

	  default:

	    addend = reg_operand(bro(sum),nsp);

	    break;

	  }

	}

	else{

	  addend = reg_operand(bro(sum),nsp);

	}

	/*addend = reg_operand (bro (sum), nsp);*/

	/* evaluate displacement .... */

	if (dreg == NO_REG)

	  dreg = getreg (nsp.fixed);

	src.reg=0;

	src.value=addend;

	operate_fmt(ins,src.value,ind,dreg);

          /* ... add it to ind in new reg */

	is.b.base = dreg;

	is.b.offset = 0;

      }

      is.adval = 1;

      setinsalt (aa, is);

      wans.answhere = aa;

      wans.ashwhere = a;

      /* ... and deliver literal base_offset */

      keepexp (e, aa);

      return wans;

    }				/* end add_ptr */

    case subptr_tag: 		/* this is nugatory - previous transforms

			       make it into addptr or reff */

    {

      exp sum = son (e);

      int   ind = reg_operand (sum, sp);

      instore isa;

      isa.adval = 1;

      sum = bro (sum);

      if (name (sum) == val_tag) {

	instore isa;

	isa.b.base = ind;

	isa.b.offset = -no (e);

	setinsalt (aa, isa);

      }

      else {

	if (dreg == 0)

	  dreg = getreg (sp.fixed);

	src.reg=0;

	src.value=ind;

	operate_fmt(i_subq,reg_operand(sum,guardreg(ind,sp)),src.value,dreg);

	isa.b.base = dreg;

	isa.b.offset = 0;

      }

      setinsalt (aa, isa);

      wans.answhere = aa;

      wans.ashwhere = a;

      keepexp (e, aa);

      return wans;

    }				/* end subptr */

    case reff_tag: {

	instore isa;

	bool bitfield = 0;

	wans = locate (son (e), sp, sh (son (e)), NO_REG);

	/* answer is going to be wans displaced by no(e) */

	if (name (sh (e)) == ptrhd) {

	  if (al1(sh(e))  == 1)

	    bitfield = 1;

	}

	switch (wans.answhere.discrim) {

	  case notinreg: {

	    isa = insalt (wans.answhere);

	    if (!isa.adval) {

	      /* wans is an actual pointer  in store, so make it into a

		 literal address.... */

	      int   reg = getreg (sp.fixed);

	      load_store(i_ldq,reg,isa.b);

	      isa.b.offset = 0;

	      isa.b.base = reg;

	      isa.adval = 1;

	    }

	      /* ... and add appropriate displacement to 

		 give result */

	      /* make sure that alignment is correct.  

	       64 bit data needs to be placed on 64 bit boundaries */

	    isa.b.offset += no (e) / 8;

	    setinsalt (wans.answhere, isa);

	    keepexp (e, wans.answhere);

	    break;

	  }

	  case inreg: {

	    /* wans is a pointer in a register */

	    isa.b.base = regalt (wans.answhere);

	    isa.adval = 1;

	    isa.b.offset = no (e) / 8;

	    setinsalt (wans.answhere, isa);

	    break;

	  }

	  default: {

	    failer ("Locate ? reg ");

	  }

	}	

	wans.ashwhere = a;

	return wans;

      }				/* end reff */

   case cont_tag: 

   case contvol_tag: 

    {

      exp s = son (e);

      ans ason;

      instore isa;

      int   reg;

      where fc;

      fc = locate (s, sp, sh (e), NO_REG);

      ason = fc.answhere;

      /* answer is going to be the contents of address represented by fc

       */

      switch (ason.discrim) {

       case notinreg: 

	{

	  isa = insalt (ason);

	  if (isa.adval) {	/* fc is a literal store address, so make

				   it into a direct one */

	    isa.adval = 0;

	    setinsalt (aa, isa);

	  }

	  else {		/* fc is an actual pointer in store .... 

				 */

	    reg = getreg (sp.fixed);

	    load_store(i_ldq,reg,isa.b);

	    /*load_store(i_lda,reg,isa.b);*/

	    /* .... so load it into reg and deliver direct base-offset

	       (reg,0) */

	    isa.b.base = reg;

	    isa.b.offset = 0;

	    setinsalt (aa, isa);

	    if (name (e) != contvol_tag && fc.ashwhere.ashalign != 1)

	      keepexp (e, aa);

	  }

	  goto breakson;

	}			/* end notinrg */

       case inreg: 

	/* this one is fraught - it depends on only being used in

	   lh-value positions from vars- take care */

	{	/* This is very dubious indeed */

	  isa.b.base = regalt (ason);

	  isa.b.offset = 0;

	  isa.adval = 1;

	  aa = ason;

	  setinsalt (aa, isa);

	  /* fc is in register, so deliver literal(!? ) base-offset */

	  goto breakson;

	}

       case infreg: 		/* ditto caveat above */

	{

	  aa = ason;

	  goto breakson;

	}

       default: {

	 failer ("Locate ? reg");

       }

      }

     breakson: 

      wans.answhere = aa;

      wans.ashwhere = a;

      return wans;

    }				/* end cont */

   case top_tag: 		/* does this ever happen ? */

    {

      setregalt (aa, 0);

      wans.answhere = aa;

      wans.ashwhere = a;

      return wans;

    }				/* end top */

   case field_tag: {

     instore isa;

     wans = locate (son (e), sp, sh (son (e)), NO_REG);

     /* answer is wans displace literally by no(e); it should always be

	a literal store adress */

     switch (wans.answhere.discrim) {

      case notinreg: {

	isa = insalt (wans.answhere);

	isa.b.offset += no (e) / 8;

	setinsalt (wans.answhere, isa);

	break;

      }

      default: 

       failer (" field should be transformed ");

     }

     wans.ashwhere = a;

     return wans;

   }				/* end field */

   default: 

    /* general catch all; evaluate e into register and deliver it as a

       literal store address */

    {

      int   r = reg_operand (e, sp);

      instore is;

      if (r == 0) {		/* guard possible result from proc - can

				   do better */

	r = getreg (sp.fixed);

	operate_fmt (i_bis,0,0,r);

      }

      is.b.base = r;

      is.b.offset = 0;

      is.adval = 1;

      setinsalt (aa, is);

      wans.answhere = aa;

      wans.ashwhere = a;

      return wans;

    }

  }

}

where locate

    PROTO_N ( ( e, sp, s, dreg ) )

    PROTO_T ( exp e X space sp X shape s X int dreg )

{

  ans ak;

  where w;

  ak = iskept (e);

  if (ak.discrim == inreg && (regalt (ak) == NO_REG)) {

    where w;

    w = locate1 (e, sp, s, dreg);

    return w;

  }

  else {			/* e has been evaluated into a register */

    w.answhere = ak;

    w.ashwhere = ashof (s);

  }

  return w;

}