/*      $OpenBSD: order.c,v 1.3 2008/04/11 20:45:52 stefan Exp $    */
/*
 * Copyright (c) 2007 Gregory McGarry (g.mcgarry@ieee.org).
 * Copyright (c) 2003 Anders Magnusson (ragge@ludd.luth.se).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 *  Machine-dependent code-generation strategy (pass 2).
 */

#include <assert.h>
#include <string.h>

#include "pass2.h"

/*
 * Check size of offset in OREG.  Called by oregok() to see if an
 * OREG can be generated.
 */
int
notoff(TWORD t, int r, CONSZ off, char *cp)
{
	if (cp && cp[0]) return 1;
	return !(off < 32768 && off > -32769);  /* YES */
}

/*
 * Generate instructions for an OREG.  Why is this routine MD?
 * Called by swmatch().
 */
void
offstar(NODE *p, int shape)
{
	NODE *r;

	if (isreg(p))
		return; /* Is already OREG */

	r = p->n_right;
	if( p->n_op == PLUS || p->n_op == MINUS ){
		if( r->n_op == ICON ){
			if (isreg(p->n_left) == 0)
				(void)geninsn(p->n_left, INAREG);
			/* Converted in ormake() */
			return;
		}
		/* usually for arraying indexing: */
		if (r->n_op == LS && r->n_right->n_op == ICON &&
		    r->n_right->n_lval == 2 && p->n_op == PLUS) {
			if (isreg(p->n_left) == 0)
				(void)geninsn(p->n_left, INAREG);
			if (isreg(r->n_left) == 0)
				(void)geninsn(r->n_left, INAREG);
			return;
		}
	}
	(void)geninsn(p, INAREG);
}

/*
 * Unable to convert to OREG (notoff() returned failure).  Output
 * suitable instructions to replace OREG.
 */
void
myormake(NODE *q)
{
        NODE *p, *r;

	if (x2debug)
		printf("myormake(%p)\n", q);

	p = q->n_left;
	if (p->n_op == PLUS && (r = p->n_right)->n_op == LS &&
	    r->n_right->n_op == ICON && r->n_right->n_lval == 2 &&
 	    p->n_left->n_op == REG && r->n_left->n_op == REG) {
		q->n_op = OREG;
 		q->n_lval = 0;
		q->n_rval = R2PACK(p->n_left->n_rval, r->n_left->n_rval,
				   r->n_right->n_lval);
		tfree(p);
	}
}

/*
 * Check to if the UMUL node can be converted into an OREG.
 */
int
shumul(NODE *p)
{
	/* Turns currently anything into OREG */
	return SOREG;
}

/*
 * Rewrite operations on binary operators (like +, -, etc...).
 * Called as a result of a failed table lookup.
 *
 * Return nonzero to retry table search on new tree, or zero to fail.
 */
int
setbin(NODE *p)
{
	return 0;

}

/*
 * Rewrite assignment operations.
 * Called as a result of a failed table lookup.
 *
 * Return nonzero to retry table search on new tree, or zero to fail.
 */
int
setasg(NODE *p, int cookie)
{
	return 0;
}

/*
 * Rewrite UMUL operation.
 * Called as a result of a failed table lookup.
 *
 * Return nonzero to retry table search on new tree, or zero to fail.
 */
int
setuni(NODE *p, int cookie)
{
	return 0;
}

/*
 * Special handling of some instruction register allocation.
 *
 * Called as a result of specifying NSPECIAL in the table.
 */
struct rspecial *
nspecial(struct optab *q)
{

	switch (q->op) {

#if !defined(ARM_HAS_FPA) && !defined(ARM_HAS_VFP)
	case UMINUS:
	case SCONV:
		if (q->lshape == SBREG && q->rshape == SAREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0R1 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SAREG && q->rshape == SBREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0 },
				{ NRES, R0R1 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SAREG && q->rshape == SAREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SBREG && q->rshape == SBREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0R1 },
				{ NRES, R0R1 },
				{ 0 }
			};
			return s;
		}

	case OPLOG:
		if (q->lshape == SBREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0R1 },
				{ NRIGHT, R2R3 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SAREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0 },
				{ NRIGHT, R1 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		}
	case PLUS:
	case MINUS:
	case MUL:
#endif
	case MOD:
	case DIV:
		if (q->lshape == SBREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0R1 },
				{ NRIGHT, R2R3 },
				{ NRES, R0R1 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SAREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0 },
				{ NRIGHT, R1 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		}
	case LS:
	case RS:
		if (q->lshape == SBREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0R1 },
				{ NRIGHT, R2 },
				{ NRES, R0R1 },
				{ 0 }
			};
			return s;
		} else if (q->lshape == SAREG) {
			static struct rspecial s[] = {
				{ NLEFT, R0 },
				{ NRIGHT, R1 },
				{ NRES, R0 },
				{ 0 }
			};
			return s;
		}
	case STASG:
		{
			static struct rspecial s[] = {
				{ NEVER, R0 },
				{ NRIGHT, R1 },
				{ NEVER, R2 },
				{ 0 } };
			return s;
		}
		break;

	default:
		break;
	}

#ifdef PCC_DEBUG
	comperr("nspecial entry %d [0x%x]: %s", q - table, q->op, q->cstring);
#endif
	return 0; /* XXX gcc */
}

/*
 * Set evaluation order of a binary node ('+','-', '*', '/', etc) if it
 * differs from default.
 */
int
setorder(NODE *p)
{
	return 0;
}

/*
 * Set registers "live" at function calls (like arguments in registers).
 * This is for liveness analysis of registers.
 */
int *
livecall(NODE *p)
{
        static int r[] = { R3, R2, R1, R0, -1 };
	int num = 1;

	if (p->n_op != CALL && p->n_op != FORTCALL && p->n_op != STCALL)
		return &r[4-0];

        for (p = p->n_right; p->n_op == CM; p = p->n_left)
                num += szty(p->n_right->n_type);
        num += szty(p->n_right->n_type);

	num = (num > 4 ? 4 : num);

        return &r[4 - num];
}

/*
 * Signal whether the instruction is acceptable for this target.
 */
int
acceptable(struct optab *op)
{
	return features(op->visit & 0xffff0000);
}