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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/680x0/common/ops_misc.c,v 1.1.1.1 1998/01/17 15:55:49 release Exp $

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

$Log: ops_misc.c,v $

 * Revision 1.1.1.1  1998/01/17  15:55:49  release

 * First version to be checked into rolling release.

 *

Revision 1.5  1997/11/13 08:27:16  ma

All avs test passed (except add_to_ptr).

Revision 1.4  1997/11/10 15:38:09  ma

.

Revision 1.3  1997/11/09 14:22:51  ma

Now is_signed is used instead of issigned. Added clear for 64 bit shapes.

Revision 1.2  1997/10/29 10:22:27  ma

Replaced use_alloca with has_alloca.

Revision 1.1.1.1  1997/10/13 12:42:57  ma

First version.

Revision 1.6  1997/10/13 08:49:52  ma

Made all pl_tests for general proc & exception handling pass.

Revision 1.5  1997/09/25 06:45:28  ma

All general_proc tests passed

Revision 1.4  1997/06/24 10:56:07  ma

Added changes for "Plumhall Patch"

Revision 1.3  1997/06/18 10:09:43  ma

Checking in before merging with Input Baseline changes.

Revision 1.2  1997/04/20 11:30:36  ma

Introduced gcproc.c & general_proc.[ch].

Added cases for apply_general_proc next to apply_proc in all files.

Revision 1.1.1.1  1997/03/14 07:50:16  ma

Imported from DRA

 * Revision 1.1.1.1  1996/09/20  10:56:57  john

 *

 * Revision 1.3  1996/07/30  16:31:50  john

 * Removed offset conversion

 *

 * Revision 1.2  1996/07/05  14:24:52  john

 * Changes for spec 3.1

 *

 * Revision 1.1.1.1  1996/03/26  15:45:16  john

 *

 * Revision 1.4  94/06/29  14:24:51  14:24:51  ra (Robert Andrews)

 * Need to be more careful about bitfields in change_variety.

 *

 * Revision 1.3  94/02/21  16:02:15  16:02:15  ra (Robert Andrews)

 * Clear up a couple of int-long confusions.

 *

 * Revision 1.2  93/03/03  14:49:46  14:49:46  ra (Robert Andrews)

 * Added error treatment processing routine, jump_overflow.

 *

 * Revision 1.1  93/02/22  17:16:26  17:16:26  ra (Robert Andrews)

 * Initial revision

 *

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

*/

#include "config.h"

#include "common_types.h"

#include "assembler.h"

#include "basicread.h"

#include "check.h"

#include "exp.h"

#include "expmacs.h"

#include "externs.h"

#include "install_fns.h"

#include "shapemacs.h"

#include "tags.h"

#include "mach.h"

#include "mach_ins.h"

#include "where.h"

#include "mach_op.h"

#include "instr.h"

#include "codex.h"

#include "instrs.h"

#include "coder.h"

#include "tests.h"

#include "operations.h"

#include "evaluate.h"

#include "utility.h"

#include "translate.h"

#include "ops_shared.h"

#include "special_exps.h"

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

  SET_OVERFLOW

  If the expression e has a long_jump error treatment then

  the global variable overflow_jump is set the the corresponding label.

  If e has the error treatment trap overflow_jump is set to -1 instead.

  The previous value of overflow_jump is returned, so it can be restored.

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

int set_overflow

    PROTO_N ( ( e ) )

    PROTO_T ( exp e )

{

   int prev_overflow_jump = overflow_jump ;

   if (! optop ( e ) ) {

      if ( pt ( e ) ) {

         overflow_jump = no(son ( pt ( e ) ) ) ; /* error jump on overflow */

         overflow_jump = ptno(pt(son(pt(e)))) ;

         overflow_jump = e->ptf.expr->sonf.expr->ptf.expr->ptf.l;

      }

      else {

         overflow_jump = -1 ; /* trap on overflow */

      }

   }

   return prev_overflow_jump ;

}

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

  CLEAR_OVERFLOW

  Restore the global variable overflow_jump with a previous value.

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

void clear_overflow

    PROTO_N ( ( prev_overflow_jump ) )

    PROTO_T ( int prev_overflow_jump )

{

   overflow_jump = prev_overflow_jump ;

}

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

  HAVE_OVERFLOW

  Used to test if overflow_jump has been set (we have an error treatment)

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

int have_overflow

    PROTO_Z ()

{

   return overflow_jump ;

}

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

  TRAP_INS

  Calls the error handler with ec as argument

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

void trap_ins

    PROTO_N ( ( ec ) )

    PROTO_T ( int ec )

{

   push ( slongsh, L32, mnw( ec ) ) ;

   callins( 0, get_error_handler() ) ;

}

/*

    OVERFLOW JUMP LABEL

    This is 0 to denote that overflows should be ignored.  Otherwise

    it gives the label to be jumped to.

*/

int overflow_jump = 0 ;

int err_continue = 0;

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

  TEST_OVERFLOW2

  If an error_treatment is specified and the previous instruction

  overflowed then either a trap or a jump is takken.

  The test condition is specified by br_ins

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

void test_overflow2

    PROTO_N ( ( br_ins ) )

    PROTO_T ( int br_ins )

{

   if ( overflow_jump == -1 ) {

      ins0( bra2trap( br_ins ) ) ;

   }

   else if ( overflow_jump ) {

      make_jump(br_ins, overflow_jump);

   }

}

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

  TEST_OVERFLOW

  If an error_treatment is specified and the previous instruction

  overflowed then either a trap or a jump is takken.

  This function finds the right test condition based on overflow_type

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

void test_overflow

    PROTO_N ( ( typ ) )

    PROTO_T ( overflow_type typ )

{

   int instr ;

   if (! have_overflow() ) return ;

   switch ( typ ) {

   case UNCONDITIONAL:  instr = m_bra ; break ;

   case ON_OVERFLOW:    instr = m_bvs ; break ;

   case ON_CARRY:       instr = m_bcs ; break ;

   case ON_FP_OVERFLOW:

   case ON_FP_CARRY:

      ins2 ( m_fmovel, L32, L32, register ( REG_FPSR ), D0, 1 ) ;

      ins2h ( m_andl, 0x00001c00, L32, D0, 1 ) ;

      instr = m_bne ;

      break ;

   case ON_FP_OPERAND_ERROR:

      ins2 ( m_fmovel, L32, L32, register ( REG_FPSR ), D0, 1 ) ;

      ins2h ( m_andl, 0x00002000, L32, D0, 1 ) ;

      instr = m_bne ;

      break;

   default:

      error("invalid overflow test");

      return ;

   }

   test_overflow2(instr);

}

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

  CHECKALLOC_STACK

  Checks if it is possible to allocate sz bytes on the stack.

  If it is not possible an exception is generated.

  else if do_alloc is TRUE, the allocation is done.

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

void checkalloc_stack

    PROTO_N ( ( sz, do_alloc ) )

    PROTO_T ( where sz X int do_alloc )

{

   int erlab = next_lab ();

   int cnlab = next_lab ();

   make_comment("check for stack overflow ...") ;

   ins2 (m_movl, 32, 32, SP, D0, 1);

   ins2 (m_subl, 32, 32, sz, D0, 1);

   make_jump (m_bcs, erlab);

   ins2 (m_cmpl, 32, 32, mw(get_stack_limit(), 0), D0, 0);

   make_jump (m_bcc, cnlab);

   make_label (erlab);

   trap_ins(f_stack_overflow);

   make_label (cnlab);

   if ( do_alloc )

   ins2 (m_movl, 32, 32, D0, SP, 1);

   make_comment("check for stack overflow done") ;

}

/*

    MARK D1 AS SPECIAL

    This flag is used to indicate that the D1 regsiter is being used

    as a special register and should be treated with care.

*/

bool D1_is_special = 0 ;

/*

    OUTPUT A CALL INSTRUCTION

    The procedure call given by fn is output.  A temporary A-register

    needs to be used when fn is not a simple procedure name.  The

    stack is then increased by longs to overwrite the procedure arguments.

*/

void callins

    PROTO_N ( ( longs, fn ) )

    PROTO_T ( long longs X exp fn )

{

    mach_op *op ;

    exp s = son ( fn ), call_exp, fn_exp ;

    bool simple_proc = 0 ;

    fn_exp = fn ;

    /* Let's see if we have the procedure at compilation time */

    if ( name ( fn ) == name_tag && ! isvar ( s ) && isglob ( s ) ) {

       exp def = son ( s ) ; /* Definition of Identify construct */

       if ( !def || name ( def ) == proc_tag || name ( def ) == general_proc_tag )

       simple_proc = 1;

    }

    /* If this is not a straight call, put the name into an A register */

    if ( ! simple_proc ) {

	where w ;

	w = zw ( fn ) ;

	if ( whereis ( w ) != Areg ) {

	    int r = next_tmp_reg () ;

	    regsinproc |= regmsk ( r ) ;

	    move ( slongsh, w, register ( r ) ) ;

	    fn_exp = register ( r ).wh_exp ;

	}

    }

    /* Now output the call instruction */

    call_exp = getexp ( proksh, nilexp, 0, fn_exp, nilexp, 0, L0, cont_tag ) ;

    op = operand ( L32, zw ( call_exp ) ) ;

    make_instr ( m_call, op, null, ~save_msk ) ;

    no_calls++ ;

    retcell ( call_exp ) ;

    dec_stack ( -longs ) ;

    have_cond = 0 ;

    return ;

}

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

    OUTPUT A JMP INSTRUCTION

    The jump to the procedure given by fn is output.  A temporary A-register

    needs to be used when fn is not a simple procedure name.

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

void jmpins

    PROTO_N ( ( fn ) )

    PROTO_T ( exp fn )

{

    mach_op *op ;

    exp s = son ( fn ), jmp_exp, fn_exp ;

    fn_exp = fn ;

    /* If this is not a straight jmp, put the name into an A register */

    if ( name ( fn ) != name_tag || isvar ( s ) || !isglob ( s ) ) {

	where w ;

	w = zw ( fn ) ;

	if ( whereis ( w ) != Areg ) {

	    int r = next_tmp_reg () ;

	    regsinproc |= regmsk ( r ) ;

	    move ( slongsh, w, register ( r ) ) ;

	    fn_exp = register ( r ).wh_exp ;

	}

    }

    /* Now output the jmp instruction */

    jmp_exp = getexp ( proksh, nilexp, 0, fn_exp, nilexp, 0, L0, cont_tag ) ;

    op = operand ( L32, zw ( jmp_exp ) ) ;

    make_instr ( m_jmp, op, null, ~save_msk ) ;

    retcell ( jmp_exp ) ;

    have_cond = 0 ;

    return ;

}

/*

    CONDITION CODES STATUS

    Many comparison instructions are unnecessary because the previous

    instruction has set the appropriate condition flags.  The flag

    have_cond deals with this.  A value of 0 indicates that we have

    no information on the flag values.  A value of 1 indicates that

    the last instruction set the flags appropriate to the where

    last_cond of size last_cond_sz.  A value of 2 is used immediately

    after a cmp instruction, the two arguments of the cmp being

    last_cond and last_cond2.  Finally a value of 3 is used immediately

    after certain move instructions to indicate that the flags are

    appropriate to either of the arguments, last_cond or last_cond_alt.

*/

bool have_cond = 0 ;

where last_cond ;

where last_cond2 ;

where last_cond_alt ;

long last_cond_sz ;

/*

    COMPARE WITH ZERO

    The value a (of shape sha and size sz) is compared with 0.  The

    cases when have_cond is 1 or 3 are dealt with by this routine.

*/

void cmp_zero

    PROTO_N ( ( sha, sz, a ) )

    PROTO_T ( shape sha X long sz X where a )

{

    long w ;

    /* Check existing condition codes */

    if ( have_cond == 1 && last_cond_sz == sz ) {

	if ( eq_where ( last_cond, a ) ) return ;

    }

    if ( have_cond == 3 && last_cond_sz == sz ) {

	if ( eq_where ( last_cond, a ) ) return ;

	if ( eq_where ( last_cond_alt, a ) ) return ;

    }

    w = whereis ( a ) ;

    if ( w == Areg ) {

	/* This does work, despite the manual */

	int instr = ins ( sz, ml_tst ) ;

	ins1 ( instr, sz, a, 0 ) ;

    } else if ( w == Freg || ( w == External && name ( sha ) == prokhd ) ) {

	/* Moving to D0 sets the flags */

	move ( sha, a, D0 ) ;

    } else {

        if ( sz == 64 ) {

            where w ;

	    w = a ;

            ins1 ( m_tstl, 32, w, 0 ) ;

            w.wh_off += 32 ;

            ins1 ( m_tstl, 32, w, 0 ) ;

        }

        else {

            int instr = ins ( sz, ml_tst ) ;

            ins1 ( instr, sz, a, 0 ) ;

        }

    }

    /* Set new condition codes */

    set_cond ( a, sz ) ;

    return ;

}

/*

    AUXILIARY COMPARISON ROUTINE

    The values a and b of size sz are compared.

*/

static bool cmp_aux

    PROTO_N ( ( sz, a, b ) )

    PROTO_T ( long sz X where a X where b )

{

    where d ;

    if ( whereis ( a ) == Freg ) {

	if ( whereis ( b ) == Freg ) {

	    move ( slongsh, a, D0 ) ;

	    move ( slongsh, b, D1 ) ;

	    regsinproc |= regmsk ( REG_D1 ) ;

	    return ( cmp_aux ( sz, D1, D0 ) ) ;

	}

	if ( eq_where ( b, D0 ) ) {

	    d = D1 ;

	    regsinproc |= regmsk ( REG_D1 ) ;

	} else {

	    d = D0 ;

	}

	move ( slongsh, a, d ) ;

	return ( cmp_aux ( sz, b, d ) ) ;

    }

    if ( whereis ( b ) == Freg ) {

	if ( eq_where ( a, D0 ) ) {

	    d = D1 ;

	    regsinproc |= regmsk ( REG_D1 ) ;

	} else {

	    d = D0 ;

	}

	move ( slongsh, b, d ) ;

	return ( cmp_aux ( sz, a, d ) ) ;

    }

    ins2_cmp ( ins ( sz, ml_cmp ), sz, sz, a, b, 0 ) ;

    have_cond = 2 ;

    last_cond = a ;

    last_cond2 = b ;

    last_cond_sz = sz ;

    return ( 1 ) ;

}

/*

    COMPARE WITH A CONSTANT

    The value a is compared with the constant value c, the type of the

    comparison being given by ntst.  The value returned by this routine

    has the same meaning as that returned by cmp.

*/

static bool cmp_const

    PROTO_N ( ( sha, sz, c, a, ntst ) )

    PROTO_T ( shape sha X long sz X where c X where a X long ntst )

{

    bool sw ;

    long v = nw ( c ) ;

    if ( is_offset ( c.wh_exp ) ) v /= 8 ;

    if ( v == 0 ) {

	if ( !is_signed ( sha ) && ntst != tst_neq && ntst != tst_eq ) {

	    /* Force an actual comparison in these cases */

	    have_cond = 0 ;

	}

	cmp_zero ( sha, sz, a ) ;

	return ( 1 ) ;

    }

    if ( v < -128 || v > 127 ) {

	sw = cmp_aux ( sz, c, a ) ;

	return ( sw ) ;

    }

    if ( interfere ( a, D0 ) ) {

	sw = cmp_aux ( sz, c, a ) ;

	return ( sw ) ;

    }

#ifdef REJECT

    if ( !output_immediately ) {

	mach_ins *p = current_ins ;

	if ( p && p->ins_no == m_moveq && p->op1->def.num == v ) {

	    sw = cmp_aux ( sz, a, register ( p->op2->def.num ) ) ;

	    last_cond2 = c ;

	    return ( !sw ) ;

	}

    }

#endif

    move ( slongsh, c, D0 ) ;

    sw = cmp_aux ( sz, a, D0 ) ;

    last_cond2 = c ;

    return ( !sw ) ;

}

/*

    MAIN COMPARISON ROUTINE

    The values var and limit of shape sha are compared for the test

    indicated by ntst.  Depending on the addressing modes of var and

    limit we may do "cmp var,limit" or "cmp limit,var".  In the first

    case we return 1 and in the second 0.  The case when have_cond is

    2 is dealt with by this routine.

*/

bool cmp

    PROTO_N ( ( sha, var, limit, ntst ) )

    PROTO_T ( shape sha X where var X where limit X long ntst )

{

    bool sw ;

    long sz = shape_size ( sha ) ;

    long rt = shtype ( sha ) ;

    long whv = whereis ( var ) ;

    long whl = whereis ( limit ) ;

#if 0

    if (name(sha) == ptrhd) {

       make_comment("HACK shape size");

       shape_size(sha) = 32 ;

       sz = 32 ;

    }

#endif

    if ( rt == Freg ) {

	/* Floating point comparisons are never swapped */

	where rv, rl ;

	have_cond = 0 ;

	if ( whv == Freg && last_use ( var ) ) {

	    rv = var ;

	} else {

	    if ( eq_where ( limit, FP0 ) ) {

		rv = FP1 ;

		regsinproc |= regmsk ( REG_FP1 ) ;

	    } else {

		rv = FP0 ;

	    }

	}

	if ( whl == Freg && last_use ( limit ) ) {

	    rl = limit ;

	} else {

	    if ( eq_where ( rv, FP0 ) ) {

		rl = FP1 ;

		regsinproc |= regmsk ( REG_FP1 ) ;

	    } else {

		rl = FP0 ;

	    }

	}

	if ( whv == Freg ) {

	    push_float ( sz, var ) ;

	    pop_float ( sz, rv ) ;

	} else {

	    move ( sha, var, rv ) ;

	}

	if ( whl == Freg ) {

	    push_float ( sz, limit ) ;

	    pop_float ( sz, rl ) ;

	} else {

	    move ( sha, limit, rl ) ;

	}

	ins2_cmp ( m_fcmpx, sz, sz, rl, rv, 0 ) ;

	return ( 1 ) ;

    }

    /* Check existing condition codes */

    if ( have_cond == 2 && last_cond_sz == sz ) {

	if ( eq_where ( last_cond, var ) &&

	     eq_where ( last_cond2, limit ) ) return ( 0 ) ;

	if ( eq_where ( last_cond, limit ) &&

	     eq_where ( last_cond2, var ) ) return ( 1 ) ;

    }

    if ( whl == Value ) {

	sw = cmp_const ( sha, sz, limit, var, ntst ) ;

	return ( sw ) ;

    }

    if ( whv == Value ) {

	sw = cmp_const ( sha, sz, var, limit, ntst ) ;

	return ( !sw ) ;

    }

    if ( whl == Dreg || whl == Areg ) {

	sw = cmp_aux ( sz, var, limit ) ;

	return ( !sw ) ;

    }

    if ( whv == Dreg || whv == Areg ) {

	sw = cmp_aux ( sz, limit, var ) ;

	return ( sw ) ;

    }

#if 0

    if(name (var.wh_exp) == name_tag && name(sha) == prokhd &&

       ((son(son(var.wh_exp))==nilexp) ||

	(name(son(son(var.wh_exp))) == proc_tag))) {

      exp proc_cont = getexp(sha,nilexp,0,var.wh_exp,nilexp,0,0,cont_tag);

      var.wh_exp = proc_cont;

    }

#endif

    if ( !interfere ( var, D0 ) ) {

	move ( sha, limit, D0 ) ;

	sw = cmp_aux ( sz, var, D0 ) ;

	last_cond2 = limit ;

	return ( !sw ) ;

    }

    if ( !interfere ( limit, D0 ) ) {

	move ( sha, var, D0 ) ;

	sw = cmp_aux ( sz, limit, D0 ) ;

	last_cond2 = var ;

	return ( sw ) ;

    }

    move ( sha, limit, D1 ) ;

    sw = cmp_aux ( sz, var, D1 ) ;

    regsinproc |= regmsk ( REG_D1 ) ;

    last_cond2 = limit ;

    return ( !sw ) ;

}

/*

    OUTPUT A PUSH INSTRUCTION

    The value wh of shape sha and size sz is pushed onto the stack.

*/

void push

    PROTO_N ( ( sha, sz, wh ) )

    PROTO_T ( shape sha X long sz X where wh )

{

    long s ;

    mach_op *op1, *op2 ;

    bool real_push = 1 ;

    if ( sz != 32 ) {

	if ( is_signed ( sha ) && ( whereis ( wh ) == Dreg ) ) {

	    change_var_sh ( slongsh, sha, wh, wh ) ;

	    push ( slongsh, L32, wh ) ;

	} else {

	    change_var_sh ( slongsh, sha, wh, D0 ) ;

	    push ( slongsh, L32, D0 ) ;

	}

	have_cond = 0 ;

	return ;

    }

    if ( stack_change ) {

	stack_change -= 32 ;

	real_push = 0 ;

	if ( stack_direction ) update_stack () ;

	s = stack_change ;

	stack_change = 0 ;

    }

    op1 = operand ( sz, wh ) ;

    if ( real_push ) {

	op2 = make_dec_sp () ;

    } else {

	op2 = make_indirect ( REG_SP, s / 8 ) ;

    }

    make_instr ( m_movl, op1, op2, 0 ) ;

    have_cond = 0 ;

    if ( real_push ) {

	stack_size -= 32 ;

    } else {

	stack_change = s ;

    }

    return ;

}

/*

    PUSH A FLOATING POINT REGISTER

    The floating-point register wh of size sz is pushed onto the stack.

*/

void push_float

    PROTO_N ( ( sz, wh ) )

    PROTO_T ( long sz X where wh )

{

    mach_op *op1 = operand ( sz, wh ) ;

    mach_op *op2 = make_dec_sp () ;

    int instr = insf ( sz, ml_fmove ) ;

    make_instr ( instr, op1, op2, 0 ) ;

    stack_size -= sz ;

    have_cond = 0 ;

    return ;

}

/*

    OUTPUT A POP OPERATION

    A value of shape sha and size sz is popped from the stack into wh.

*/

void pop

    PROTO_N ( ( sha, sz, wh ) )

    PROTO_T ( shape sha X long sz X where wh )

{

    mach_op *op1, *op2 ;

    if ( sz != 32 ) {

	if ( whereis ( wh ) == Dreg ) {

	    pop ( slongsh, L32, wh ) ;

	    change_var_sh ( sha, slongsh, wh, wh ) ;

	} else {

	    pop ( slongsh, L32, D0 ) ;

	    change_var_sh ( sha, slongsh, D0, wh ) ;

	}

	have_cond = 0 ;

	return ;

    }

    op1 = make_inc_sp () ;

    op2 = operand ( sz, wh ) ;

    make_instr ( m_movl, op1, op2, 0 ) ;

    have_cond = 0 ;

    stack_size += sz ;

    return ;

}

/*

    POP A FLOATING POINT REGISTER

    A value of size sz is popped from the stack into the floating-point

    register wh.

*/

void pop_float

    PROTO_N ( ( sz, wh ) )

    PROTO_T ( long sz X where wh )

{

    mach_op *op1 = make_inc_sp () ;

    mach_op *op2 = operand ( sz, wh ) ;

    int instr = insf ( sz, ml_fmove ) ;

    make_instr ( instr, op1, op2, 0 ) ;

    have_cond = 0 ;

    stack_size += sz ;

    return ;

}

/*

    MOVE AN ADDRESS INTO A TEMPORARY REGISTER

    The effective address of wh is loaded into a temporary register and

    the register number is returned.  By default, register r is used,

    but if try is true we see if we can do better.

*/

static int tmp_mova

    PROTO_N ( ( wh, r, try ) )

    PROTO_T ( where wh X int r X bool try )

{

    tmp_reg_prefer = r ;

    mova ( wh, register ( r ) ) ;

    if ( try && !output_immediately && current_ins ) {

	int i = current_ins->ins_no ;

	if ( i == m_lea || i == m_movl ) {

	    mach_op *op1 = current_ins->op1 ;

	    mach_op *op2 = current_ins->op2 ;

	    if ( op2->type == MACH_REG && op2->def.num == r ) {

		int t = r ;

		if ( i == m_lea ) {

		    if ( op1->type == MACH_CONT ) {

			op1 = op1->of ;

			if ( op1->type == MACH_REG && op1->plus == null ) {

			    t = op1->def.num ;

			}

		    }

		} else {

		    if ( op1->type == MACH_REG ) t = op1->def.num ;

		}

		if ( t != r ) {

		    current_ins->ins_no = m_ignore_ins ;

		    op2->def.num = t ;

		    r = t ;

		}

	    }

	}

    }

    regsinproc |= regmsk ( r ) ;

    return ( r ) ;

}

/*

    MOVE A CONSTANT VALUE

    The constant value c is assigned to the where to (of shape sha and

    size sz).

*/

void move_const

    PROTO_N ( ( sha, sz, c, to ) )

    PROTO_T ( shape sha X long sz X long c X where to )

{

    int instr ;

    int whto = whereis ( to ) ;

    if ( c == 0 ) {

	/* Clearing is a special case */

	if ( whto == Dreg ) {

	    ins2n ( m_moveq, 0, L32, to, 1 ) ;

	    set_cond ( to, sz ) ;

	    return ;

	}

	if ( whto == Areg ) {

	    ins2 ( m_subl, L32, L32, to, to, 1 ) ;

	    have_cond = 0 ;

	    return ;

	}

        if ( sz == 64 ) {

            where w ;

	    w = to ;

            ins1 ( m_clrl, 32, w, 0 ) ;

            w.wh_off += 32 ;

            ins1 ( m_clrl, 32, w, 0 ) ;

        }

        else {