source: mainline/uspace/app/pcc/arch/pdp11/order.c@ 6037308

/*      $Id: order.c,v 1.3 2008/10/04 08:43:17 ragge Exp $      */
/*
 * 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.
 */


# include "pass2.h"

#include <string.h>

int canaddr(NODE *);

/* is it legal to make an OREG or NAME entry which has an
 * offset of off, (from a register of r), if the
 * resulting thing had type t */
int
notoff(TWORD t, int r, CONSZ off, char *cp)
{
        return(0);  /* YES */
}

static int
inctree(NODE *p)
{
        if (p->n_op == MINUS && p->n_left->n_op == ASSIGN && 
            p->n_left->n_right->n_op == PLUS &&
            treecmp(p->n_left->n_left, p->n_left->n_right->n_left) &&
            p->n_right->n_op == ICON && p->n_right->n_lval == 1 &&
            p->n_left->n_right->n_right->n_op == ICON &&
            p->n_left->n_right->n_right->n_lval == 1) {
                /* post-increment by 1; (r0)+ */
                if (isreg(p->n_left->n_left)) /* Ignore if index not in reg */
                        return 1;
        }
        return 0;
}

/*
 * Turn a UMUL-referenced node into OREG.
 * Be careful about register classes, this is a place where classes change.
 */
void
offstar(NODE *p, int shape)
{
        if (x2debug)
                printf("offstar(%p)\n", p);

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

        if (p->n_op == UMUL)
                p = p->n_left; /* double indexed umul */

        if (inctree(p)) /* Do post-inc conversion */
                return;

        if( p->n_op == PLUS || p->n_op == MINUS ){
                if (p->n_right->n_op == ICON) {
                        if (isreg(p->n_left) == 0)
                                (void)geninsn(p->n_left, INAREG);
                        /* Converted in ormake() */
                        return;
                }
        }
        (void)geninsn(p, INAREG);
}

/*
 * Do the actual conversion of offstar-found OREGs into real OREGs.
 */
void
myormake(NODE *p)
{
        NODE *q = p->n_left;

        if (x2debug) {
                printf("myormake(%p)\n", p);
                fwalk(p, e2print, 0);
        }
        if (inctree(q)) {
                if (q->n_left->n_left->n_op == TEMP)
                        return;
                p->n_op = OREG;
                p->n_lval = 0; /* Add support for index offset */
                p->n_rval = R2PACK(regno(q->n_left->n_left), 0, 1);
                tfree(q);
                return;
        }
        if (q->n_op != OREG)
                return;
        p->n_op = OREG;
        p->n_lval = q->n_lval;
        p->n_rval = R2PACK(q->n_rval, 0, 0);
        nfree(q);
}

/*
 * Shape matches for UMUL.  Cooperates with offstar().
 */
int
shumul(NODE *p, int shape)
{

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

        if (p->n_op == NAME && (shape & STARNM))
                return SRDIR;
        if (shape & SOREG)
                return SROREG;  /* Calls offstar */
        return SRNOPE;
}

/*
 * Rewrite operations on binary operators (like +, -, etc...).
 * Called as a result of table lookup.
 */
int
setbin(NODE *p)
{

        if (x2debug)
                printf("setbin(%p)\n", p);
        return 0;

}

/* setup for assignment operator */
int
setasg(NODE *p, int cookie)
{
        if (x2debug)
                printf("setasg(%p)\n", p);
        return(0);
}

/* setup for unary operator */
int
setuni(NODE *p, int cookie)
{
        return(0);
}

/*
 * Special handling of some instruction register allocation.
 */
struct rspecial *
nspecial(struct optab *q)
{
        switch (q->op) {
        case MUL:
                if (q->visit == INAREG) {
                        static struct rspecial s[] = { { NLEFT, R1 }, { 0 } };
                        return s;
                } else if (q->visit == INBREG) {
                        static struct rspecial s[] = { { NRES, R01 }, { 0 } };
                        return s;
                }
                break;

        case DIV:
                if (q->visit == INAREG && q->ltype == TUNSIGNED) {
                        static struct rspecial s[] = {
                           { NLEFT, R0 }, { NRIGHT, R1 }, { NRES, R0 }, { 0 } };
                        return s;
                } else if (q->visit == INAREG) {
                        static struct rspecial s[] = {
                            { NRES, R0 }, { 0 } };
                        return s;
                } else if (q->visit == INBREG) {
                        static struct rspecial s[] = { { NRES, R01 }, { 0 } };
                        return s;
                }
                break;

        case MOD:
                if (q->visit == INAREG && q->ltype == TUNSIGNED) {
                        static struct rspecial s[] = {
                           { NLEFT, R0 }, { NRIGHT, R1 }, { NRES, R0 }, { 0 } };
                        return s;
                } else if (q->visit == INBREG) {
                        static struct rspecial s[] = { { NRES, R01 }, { 0 } };
                        return s;
                }
                break;

        case SCONV:
                if (q->lshape == SAREG) {
                        static struct rspecial s[] = {
                            { NLEFT, R1 }, { NRES, R01 }, { 0 } };
                        return s;
                }
                break;
        } 
        comperr("nspecial entry %d", q - table);
        return 0; /* XXX gcc */
}

/*
 * Set evaluation order of a binary node if it differs from default.
 */
int
setorder(NODE *p)
{
        return 0; /* nothing differs on x86 */
}

/*
 * set registers in calling conventions live.
 */
int *
livecall(NODE *p)
{
        static int r[] = { -1 };

        return r;
}

/*
 * Signal whether the instruction is acceptable for this target.
 */
int
acceptable(struct optab *op)
{
        return 1;
}