/*      $NetBSD: gsp_sym.c,v 1.10 2025/11/24 08:04:28 nia Exp $ */
/*
 * GSP assembler - symbol table
 *
 * Copyright (c) 1993 Paul Mackerras.
 * 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 <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: gsp_sym.c,v 1.10 2025/11/24 08:04:28 nia Exp $");
#endif

#include <stdio.h>
#include <string.h>
#include <util.h>
#include "gsp_ass.h"

#define NHASH   64              /* must be power of 2 */

symbol symbol_hash[NHASH];

void define_sym(char *, unsigned, unsigned, int);

symbol
lookup(char *id, bool makeit)
{
        symbol ptr, p, *pp;
        int h;
        char *ip;

        h = 0;
        for( ip = id; *ip != 0; )
                h = (h << 1) + *ip++;
        h &= NHASH-1;
        for( pp = &symbol_hash[h]; (p = *pp) != NULL; pp = &p->next )
                if( (h = strcmp(id, p->name)) == 0 )
                        return p;
                else if( h < 0 )
                        break;
        if( !makeit )
                return NULL;
        ptr = emalloc(sizeof(struct symbol) + strlen(id));
        ptr->ndefn = 0;
        ptr->flags = 0;
        ptr->value = 0;
        ptr->lineno = NOT_YET;
        strcpy(ptr->name, id);
        *pp = ptr;
        ptr->next = p;
        ptr->nlab = NULL;
        return ptr;
}

void
define_sym(char *id, unsigned val, unsigned lno, int flags)
{
        symbol ptr;

        ptr = lookup(id, TRUE);
        if( (ptr->flags & SET_LABEL) == 0 ){
                if( ptr->ndefn >= 2 ){
                        perr("Multiply defined label %s", id);
                        if( (flags & SET_LABEL) != 0 )
                                return;
                } else if( pass2 && ptr->value != val )
                        perr("Phase error on label %s (%#x -> %#x)",
                                id, ptr->value, val);
        }
        ptr->flags = flags;
        ptr->ndefn += 1;
        ptr->value = val;
        ptr->lineno = lno;
}

void
set_label(char *id)
{
        if( id != NULL ){
                define_sym(id, pc, lineno, DEFINED);
                if( pass2 )
                        do_list_pc();
        }
}

void
do_asg(char *name, expr value, int flags)
{
        int32_t val;
        unsigned lno;

        if( eval_expr(value, &val, &lno) )
                flags |= DEFINED;
        if( lno < lineno )
                lno = lineno;
        define_sym(name, val, lno, flags);
        if( pass2 )
                do_show_val(val);
}

void
set_numeric_label(int lnum)
{
        symbol bp, fp;
        struct numlab *nl;
        char id[32];

        /* define the backward reference symbol */
        sprintf(id, "%dB", lnum);
        bp = lookup(id, TRUE);
        bp->flags = NUMERIC_LABEL | DEFINED;
        bp->value = pc;
        bp->lineno = lineno;

        /* look up the forward reference symbol */
        id[strlen(id) - 1] = 'F';
        fp = lookup(id, TRUE);

        if( !pass2 ){
                /* Record a new numeric label and link it into the
                   chain.  fp->nlab points to the head of the chain,
                   bp->nlab points to the tail.  */
                new(nl);
                nl->value = pc;
                nl->lineno = lineno;
                nl->next = NULL;
                if( bp->nlab == NULL )
                        fp->nlab = nl;
                else
                        bp->nlab->next = nl;
                bp->nlab = nl;
                fp->flags = NUMERIC_LABEL;
        } else {
                /* Advance to the next numeric label entry in the chain
                   and update the value of the forward reference symbol. */
                if( pc != fp->value )
                        perr("Phase error on numeric label %d (%#x -> %#x)",
                                lnum, fp->value, pc);
                nl = fp->nlab;
                nl = nl->next;
                if( nl == NULL ){
                        /* no more labels of this number */
                        /* forward references are now undefined */
                        fp->flags &= ~DEFINED;
                        fp->lineno = NOT_YET;
                        fp->value = 0;
                } else {
                        fp->lineno = nl->lineno;
                        fp->value = nl->value;
                        fp->nlab = nl;
                }
                do_list_pc();
        }
}

/* At the beginning of pass 2, reset all of the numeric labels.
   Backward references become undefined, forward references are defined
   by the first instance of the label. */
void
reset_numeric_labels()
{
        symbol p;
        struct numlab *nl;
        int h;

        for( h = 0; h < NHASH; ++h ) {
                for( p = symbol_hash[h]; p != NULL; p = p->next ) {
                        if( (p->flags & NUMERIC_LABEL) != 0 ) {
                                if( (p->flags & DEFINED) != 0 ) {
                                        /* a backward reference */
                                        p->flags &= ~DEFINED;
                                } else {
                                        /* a forward reference */
                                        p->flags |= DEFINED;
                                        nl = p->nlab;
                                        p->value = nl->value;
                                        p->lineno = nl->lineno;
                                }
                        }
                }
        }
}