/* r52adr.c */

/*
 * Modified from the code of Alan R. Baldwin by Marko Mäkelä
 * in the 28th of February 1993
 *
 * Author of the original file for 6800:
 *
 * Alan R. Baldwin
 * 721 Berkeley St.
 * Kent, Ohio  44240
 * United States of America
 *
 * The one who modified it for 65C02:
 *
 * Marko Mäkelä
 * Sillitie 10 A
 * 01480 Vantaa
 * Finland
 * Internet: Marko.Makela@Helsinki.Fi
 * EARN/BitNet: msmakela@finuh
 */

#include <stdio.h>
#include <setjmp.h>
#include "asm.h"
#include "r6502.h"

int
addr(esp)
register struct expr *esp;
{
	register c;

	if ((c = getnb()) == '#') {
		expr(esp, 0);
		esp->e_mode = S_IMM;
		if (esp->e_addr & ~0xFF)
			aerr();
	} else
	if (c == '[') {
		expr(esp, 0);
		if ((c = getnb()) == ']') {
			if (more()) {
				comma();
				if (admode(xy) != S_Y)
					qerr();
				esp->e_mode = S_IZPY;
				if (esp->e_addr & ~0xFF)
					err('d');
            } else
				esp->e_mode = (esp->e_addr & ~0xFF) ? S_IABS : S_IZP;
		} else {
			unget(c);
			comma();
			if (admode(xy) != S_X)
				qerr();
			esp->e_mode = (esp->e_addr & ~0xFF) ? S_IABSX : S_IZPX;
			if (getnb() != ']' || more())
				qerr();
		}
	} else {
		unget(c);

		if (admode(a)) {
			if (more())
				qerr();
			esp->e_mode = S_ACCUM;
		} else
		if (!more()) {
			esp->e_mode = S_IMP;
		} else {
			expr(esp,0);

			if (!more())
				esp->e_mode = (esp->e_addr & ~0xFF) ? S_ABS : S_ZP;
			else {
				comma();
				switch (admode(xy)) {
					case S_X:
						esp->e_mode = (esp->e_addr & ~0xFF) ? S_ABSX : S_ZPX;
						break;
					case S_Y:
						esp->e_mode = (esp->e_addr & ~0xFF) ? S_ABSY : S_ZPY;
						break;
					default:
						qerr();
				}
			}
		}
    }
	return (esp->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)
register struct adsym *sp;
{
	register char *ptr;
	register int i;
	unget(getnb());
	i = 0;
	while ( *(ptr = (char *) &sp[i]) ) {
		if (srch(ptr)) {
			return(sp[i].a_val);
		}
		i++;
	}
	return(0);
}

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

#if	CASE_SENSITIVE
	while (*ptr && *str) {
		if(*ptr != *str)
			break;
		ptr++;
		str++;
	}
	if (*ptr == *str) {
		ip = ptr;
		return(1);
	}
#else
	while (*ptr && *str) {
		if(ccase[*ptr] != ccase[*str])
			break;
		ptr++;
		str++;
	}
	if (ccase[*ptr] == ccase[*str]) {
		ip = ptr;
		return(1);
	}
#endif

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

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

struct adsym	a[] = { 	/* accumulator */
	"a",	S_A,
	"",	0x00
};

struct adsym	xy[] = {	/* x or y registers */
	"x",    S_X,
	"y",    S_Y,
	"",	0x00
};