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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.

*/

/*

$Log: getregs.c,v $

 * Revision 1.1.1.1  1998/01/17  15:56:02  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1995/12/18  13:11:23  wfs

 * Put hppatrans uder cvs control. Major Changes made since last release

 * include:

 * (i) PIC code generation.

 * (ii) Profiling.

 * (iii) Dynamic Initialization.

 * (iv) Debugging of Exception Handling and Diagnostics.

 *

 * Revision 5.0  1995/08/25  13:42:58  wfs

 * Preperation for August 25 Glue release

 *

 * Revision 3.4  1995/08/25  09:26:59  wfs

 * register synonyms changed. some code removed which had become

 * superfluous after changes to the way registers were allocated

 *

 * Revision 3.4  1995/08/25  09:26:59  wfs

 * register synonyms changed. some code removed which had become

 * superfluous after changes to the way registers were allocated

 *

 * Revision 3.1  95/04/10  16:26:30  16:26:30  wfs (William Simmonds)

 * Apr95 tape version.

 * 

 * Revision 3.0  95/03/30  11:17:11  11:17:11  wfs (William Simmonds)

 * Mar95 tape version with CRCR95_178 bug fix.

 * 

 * Revision 2.0  95/03/15  15:26:57  15:26:57  wfs (William Simmonds)

 * spec 3.1 changes implemented, tests outstanding.

 * 

 * Revision 1.1  95/01/11  13:07:36  13:07:36  wfs (William Simmonds)

 * Initial revision

 * 

*/

#define HPPATRANS_CODE

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

		getregs.c

	Routines for choosing temporary registers. The next free

register is chosen cyclically from available t regs.

	The parameter is usually taken from a value of type space

(which has bits for fixed and floating regs).  A clear bit indicates

that the corresponding register is free for use.

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

#include "config.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"

/* next fixed reg to be allocated */

static int currentfix = R_FIRST;

static long choosefix = RMASK(R_FIRST);

/* next float reg to be allocated */

static int currentfloat = R_FLT_FIRST;

static long choosefloat = RMASK(R_FLT_FIRST);

/* reset getreg() and getfreg() back to start of sequence for proc 'tg' */

/* (help register numbers be backward compatible). */

void settempregs 

    PROTO_N ( ( tg ) )

    PROTO_T ( exp tg )

{

  /*ARGSUSED*/

  currentfix = GR2;

  choosefix = RMASK(currentfix);

  currentfloat = 1;

  choosefloat = RMASK(currentfloat);

}

/* get a free temporary fixed pt reg */

int getreg

    PROTO_N ( ( fixed ) )

    PROTO_T ( long fixed )

{

  /*

   * Choose reg from set 'fixed'. Chosen in a cyclic order, to give good

   * chance for peep-hole optimiser finding something useful lying around. Bit

   * set in set 'fixed' means it is unavailable, we search for 0 bit.

   */

  int reg = -1;

  long start = choosefix;

  FULLCOMMENT3("getreg: from %#x, choosefix=%#x currentfix=%d", fixed, choosefix, currentfix);

  /* currentfix and choosefix are in step, one the reg number, one the mask */

  assert(choosefix == RMASK(currentfix));

  for (;;)

  {

    if ((choosefix & fixed) == 0)

      reg = currentfix;

    assert(reg != GR0); 	/* hard wired to 0, shouldn't be in set */

    assert(reg != GR1);	       /* ad-hoc temporary                     */

    assert(reg != DP);        /* %dp must not be changed              */

    assert(reg != SP);       /* %sp must not be changed              */

    if (currentfix == R_LAST)

    {

       /* back to start */

       currentfix = R_FIRST;

       choosefix = RMASK(R_FIRST);

    }

    else

    {

       /* next reg */

       currentfix++;

       choosefix = choosefix << 1;

    }

    if (reg != -1)

    {

       FULLCOMMENT1("getreg: allocating %d", reg);

       assert(IS_TREG(reg));

       return reg;

    }

    if (choosefix == start)

    {

       fail("getreg: too many regs required");

       return GR0;

    }

  }

  /* NOTREACHED */

}

int getfreg 

    PROTO_N ( ( fl ) )

    PROTO_T ( long fl ) /* get a free temporary floating reg */

{

  /*

   * Choose reg from set 'fl'. Chosen in a cyclic order, to give good chance

   * for peep-hole optimiser finding something useful lying around. Bit set in

   * set 'float' means it is unavailable, we search for 0 bit.

   */

  int reg = -1;

  long start = choosefloat;

  FULLCOMMENT3("getfreg: from %#x, choosefloat=%#x currentfloat=%d", fl, choosefloat, currentfloat);

  /*

   * currentfloat and choosefloat are in step, one the reg number, one the

   * mask

   */

  assert(choosefloat == RMASK(currentfloat));

  for (;;)

  {

    if (((choosefloat & fl) == 0) && IS_FLT_TREG(currentfloat))

       reg = currentfloat;

    if (currentfloat == R_FLT_LAST)

    {

      /* back to start */

      currentfloat = R_FLT_FIRST;

      choosefloat = RMASK(R_FLT_FIRST);

    }

    else

    {

      /* next reg */

      currentfloat++;

      choosefloat = choosefloat << 1;

    }

    if (reg != -1)

    {

      FULLCOMMENT1("getfreg: allocating %d", reg);

      assert(IS_FLT_TREG(reg));

      return reg;

    }

    if (choosefloat == start)

    {

      fail("getfreg: too many floating point regs required");

      return 0;

    }

  }

}