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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.

*/

/*

			    VERSION INFORMATION

			    ===================

--------------------------------------------------------------------------

$Header: /u/g/release/CVSROOT/Source/src/installers/sparc/common/getregs.c,v 1.1.1.1 1998/01/17 15:55:54 release Exp $

--------------------------------------------------------------------------

$Log: getregs.c,v $

 * Revision 1.1.1.1  1998/01/17  15:55:54  release

 * First version to be checked into rolling release.

 *

 * Revision 1.4  1997/08/23  13:53:43  pwe

 * initial ANDF-DE

 *

 * Revision 1.3  1996/09/18  12:03:33  pwe

 * fixed PIC_code

 *

 * Revision 1.2  1995/05/26  12:58:14  john

 * Reformatting

 *

 * Revision 1.1.1.1  1995/03/13  10:18:36  john

 * Entered into CVS

 *

 * Revision 1.2  1994/07/07  16:11:33  djch

 * Jul94 tape

 *

 * Revision 1.2  1994/07/07  16:11:33  djch

 * Jul94 tape

 *

 * Revision 1.1  1994/05/03  14:49:35  djch

 * Initial revision

 *

 * Revision 1.3  93/08/27  11:25:51  11:25:51  ra (Robert Andrews)

 * Tell lint that settempregs doesn't use its argument.

 * 

 * Revision 1.2  93/07/12  15:13:35  15:13:35  ra (Robert Andrews)

 * Reformatted.

 * 

 * Revision 1.1  93/06/24  14:58:20  14:58:20  ra (Robert Andrews)

 * Initial revision

 * 

--------------------------------------------------------------------------

*/

#define SPARCTRANS_CODE

/*

    Routines for choosing temporary registers.

*/

#include "config.h"

#include "common_types.h"

#include "myassert.h"

#include "regmacs.h"

#include "proctypes.h"

#include "exptypes.h"

#include "procrec.h"

#include "expmacs.h"

#include "exp.h"

#include "addrtypes.h"

#include "regexps.h"

#include "tags.h"

#include "expmacs.h"

#include "bitsmacs.h"

#include "getregs.h"

/*

    THE NEXT FIXED REGISTER TO BE ALLOCATED

*/

static int currentfix = R_FIRST ;

static long choosefix = RMASK ( R_FIRST ) ;

/*

    THE NEXT FLOATING REGISTER TO BE ALLOCATED

*/

static int currentfloat = R_FLT_FIRST ;

static long choosefloat = RMASK ( R_FLT_FIRST ) ;

/*

    INITIALIZE REGISTER ALLOCATION VARIABLES

    This is called at the start of each procedure.

*/

void settempregs 

    PROTO_N ( ( tg ) )

    PROTO_T ( exp tg ){

  currentfix = R_O0 ;

  choosefix = RMASK ( currentfix ) ;

  currentfloat = 1 ;

  choosefloat = RMASK ( currentfloat ) ;

  return ;

}

/*

  GET THE NEXT FREE TEMPORARY FIXED REGISTER

  The argument fixed gives the bitmask of all the unavailable registers.

  Avoid R_O7 until last, so it's available for PIC_code case.

*/

int getreg 

    PROTO_N ( ( fixed ) )

    PROTO_T ( long fixed ){

  int reg = -1 ;

  long start = choosefix ;

  assert ( choosefix == RMASK ( currentfix ) ) ;

  for ( ; ; ) {

    /* Check if register is free */

    if ( ( choosefix & fixed ) == 0 && currentfix != R_O7) reg = currentfix ;

    /* Work out the next register (cyclic) */

    if ( currentfix == R_LAST ) {

      currentfix = R_FIRST ;

      choosefix = RMASK ( R_FIRST ) ;

    } 

    else {

      currentfix++ ;

      choosefix = choosefix << 1 ;

    }

    if ( reg != -1 ) {

      /* Register found */

      assert ( IS_TREG ( reg ) ) ;

      assert ( reg != R_G0 ) ;	/* %g0 is always 0 */

      assert ( reg != R_G1 ) ;	/* %g1 is used for other purposes */

      return ( reg ) ;

    }

    if ( choosefix == start ) {

      /* Back where we started */

      if ( (fixed & RMASK (R_O7)) == 0 ) {

	return (R_O7);

      }

      fail ( "Can't allocate temporary register" ) ;

      return ( R_G1 ) ;

    }

  }

  /* NOT REACHED */

}

/*

  GET THE NEXT FREE TEMPORARY FLOATING REGISTER

  The argument fl gives the bitmask of all the unavailable registers.

*/

int getfreg 

    PROTO_N ( ( fl ) )

    PROTO_T ( long fl ){

  int reg = -1 ;

  long start = choosefloat ;

  assert ( choosefloat == RMASK ( currentfloat ) ) ;

  for ( ; ; ) {

    /* Check if register is free */

    if ( ( choosefloat & fl ) == 0 ) reg = currentfloat ;

    /* Work out the next register (cyclic) */

    if ( currentfloat == R_FLT_LAST ) {

      currentfloat = R_FLT_FIRST ;

      choosefloat = RMASK ( R_FLT_FIRST ) ;

    } 

    else {

      currentfloat++ ;

      choosefloat = choosefloat << 1 ;

    }

    if ( reg != -1 ) {

      /* Register found */

      assert ( IS_FLT_TREG ( reg ) ) ;

      return ( reg ) ;

    }

    if ( choosefloat == start ) {

      fail ( "Can't allocate temporary floating register" ) ;

      return ( 0 ) ;

    }

  }

  /* NOT REACHED */

}