/* i61adr.c */

/*
 *  Copyright (C) 2013-2014  Alan R. Baldwin
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * Alan R. Baldwin
 * 721 Berkeley St.
 * Kent, Ohio  44240
 */

#include "asxxxx.h"
#include "i6100.h"

int
addr(esp)
struct expr *esp;
{
	int c, d, e_mode;

	/*
	 * Indirect Addressing Mode
	 */
	e_mode = admode(ind);
	/*
	 * Explicit Direct Page Mode
	 */
	if ((c = getnb()) == '*') {
		e_mode |= S_ZP;
	} else {
		unget(c);
	}
	/*
	 * Indirect Addressing Mode
	 */
	if ((d = getnb()) == '[') {
		if ((c = getnb()) == '*') {
			if (e_mode & S_ZP) {
				aerr();
			} else {
				e_mode |= S_ZP;
			}
		} else {
			unget(c);
		}
		if (e_mode & S_IND) {
			aerr();
		} else {
			e_mode |= S_IND;
		}
	} else {
		unget(d);
	}
	/*
	 * Evaluate Expresion
	 */
	expr(esp, 0);
	/*
	 * End of Indirect Addressing Mode
	 */
	if ((d == '[') && (getnb() != ']')) {
		qerr();
	}
	/*
	 * Zero Page Check
	 */
	if (zpage(esp) == 1) {
		e_mode |= S_ZP;
	}
	return (esp->e_mode = e_mode);
}

/*
 * Enter admode() to search a specific addressing mode table
 * for a match. Return the addressing value on a match or
 * zero for no match.
 */
int
admode(sp)
struct adsym *sp;
{
	char *ptr;
	int i;
	char *ips;

	ips = ip;
	unget(getnb());

	i = 0;
	while ( *(ptr = &sp[i].a_str[0]) ) {
		if (srch(ptr)) {
			return(sp[i].a_val);
		}
		i++;
	}
	ip = ips;
	return(0);
}

/*
 *	srch --- does string match ?
 */
int
srch(str)
char *str;
{
	char *ptr;
	ptr = ip;

	while (*ptr && *str) {
		if(ccase[*ptr & 0x007F] != ccase[*str & 0x007F])
			break;
		ptr++;
		str++;
	}
	if (ccase[*ptr & 0x007F] == ccase[*str & 0x007F]) {
		ip = ptr;
		return(1);
	}

	if (!*str)
		if (any(*ptr," \t\n,];")) {
			ip = ptr;
			return(1);
		}
	return(0);
}

/*
 *	any --- does str contain c?
 */
int
any(c,str)
int c;
char *str;
{
	while (*str)
		if(*str++ == c)
			return(1);
	return(0);
}

struct adsym	ind[] = {	/* i for indirect */
	{	"i",	S_IND	},
	{	"",	0x00	}
};

/*
 *	zpage --- check for direct page address equivalent
 */
int zpage(esp)
struct expr *esp;
{
	return((!esp->e_flag) && (esp->e_base.e_ap==NULL) && !(esp->e_addr & ~0x7F));
}
