/* ez80adr.c */

/*
 *  Copyright (C) 1989-2026  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
 *
 *
 * Ported by Patrick Head
 * from the ASZ80 assembler.
 *
 * patrick at phead dot net
 */

#include "asxxxx.h"
#include "ez80.h"

/*
 * Read an address specifier. Pack the
 * address information into the supplied
 * `expr' structure. Return the mode of
 * the address.
 *
 * This addr(esp) routine performs the following addressing decoding:
 *
 *	address		mode		flag		addr		base
 *	#n		S_IMMED		0		n		NULL
 *	label		s_type		----		s_addr		s_area
 *	(REG)		S_IND+icode	0		0		NULL
 *	(label)		S_INDM		----		s_addr		s_area
 *	(REG+offset)	S_IND+icode	----		offset		----
 *	offset(REG)	S_IND+icode	----		offset		----
 */
int
addr(struct expr *esp)
{
	int c, mode, indx;
	char *p;

	/* fix order of '<', '>', and '#' */
	p = ip;
	if (((c = getnb()) == '<') || (c == '>')) {
		p = ip-1;
		if (getnb() == '#') {
			*p = *(ip-1);
			*(ip-1) = c;
		}
	}
	ip = p;

	if ((c = getnb()) == '#') {
		expr(esp);
		esp->e_mode = S_IMMED;
	} else
	if (c == LFIND) {
		/*  (a), (b), (c), (d), (h), (l)  */
		if ((indx = admode(R8)) != 0) {
			mode = S_INDB;
		} else
		/*  (bc), (de), (hl), (sp), (ix), (iy)  */
		if ((indx = admode(RX)) != 0) {
			mode = S_INDR;
		} else
		/*  (i), (r), (ixh), (ixl), (iyh), (iyl), (mb)  */
		if ((indx = admode(R8X)) != 0) {
			mode = S_R8X;
			xerr('a', "Indexed mode is invalid.");
		} else
		/*  (af), (af')  */
		if ((indx = admode(RXX)) != 0) {
			mode = S_RXX;
			xerr('a', "Indexed mode is invalid.");
		} else
		/*  (mn)  */
		{
			mode = S_INDM;
			expr(esp);
			esp->e_mode = mode;
		}
		if (indx) {
			esp->e_mode = mode + (indx&0xFF);
			esp->e_base.e_ap = NULL;
		}
		if ((c = getnb()) != RTIND) {
			unget(c);
			/*  (ix+d), (iy+d)  */
			if (indx && ((indx&0xFF)==IX || (indx&0xFF)==IY)) {
				expr(esp);
				esp->e_mode = S_INDR + (indx&0xFF);
			}
			if ((c = getnb()) != RTIND)
				xerr('q', "Missing ')'.");
		}
	} else {
		unget(c);
		/*  a, b, c, d, h, l  */
		if ((indx = admode(R8)) != 0) {
			mode = S_R8;
		} else
		/*  bc, de, hl, sp, ix, iy  */
		if ((indx = admode(RX)) != 0) {
			mode = S_RX;
		} else	
		/*  i, r, ixh, ixl, iyh, iyl, mb  */
		if ((indx = admode(R8X)) != 0) {
			mode = S_R8X;
		} else
		/*  af, af'  */
		if ((indx = admode(RXX)) != 0) {
			mode = S_RXX;
		} else
		/*  mn  */
		{
			mode = S_USER;
			expr(esp);
			esp->e_mode = mode;
		}
		if (indx) {
			esp->e_addr = indx & 0xFF;
			esp->e_mode = mode;
			esp->e_base.e_ap = NULL;
		}
		if ((c = getnb()) == LFIND) {
			/*  d(ix), d(iy)  */
			if (indx==0 && (indx=admode(RX))!=0 &&
			   ((indx&0xFF)==IX || (indx&0xFF)==IY)) {
				esp->e_mode = S_INDR + (indx&0xFF);
			} else {
				xerr('a', "Expected form is D(IX) or D(IY).");
			}
			if ((c = getnb()) != RTIND)
				xerr('q', "Missing ')'.");
		} else {
			unget(c);
		}
	}
	return (esp->e_mode);
}

/*
 * When building a table that has variations of a common
 * symbol always start with the most complex symbol first.
 * for example if x, x+, and x++ are in the same table
 * the order should be x++, x+, and then x.  The search
 * order is then most to least complex.
 */

/*
 * When searching symbol tables that contain characters
 * not of type LTR16, eg with '-' or '+', always search
 * the more complex symbol tables first. For example:
 * searching for x+ will match the first part of x++,
 * a false match if the table with x+ is searched
 * before the table with x++.
 */

/*
 * 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(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(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 (!(ctype[*ptr & 0x007F] & LTR16)) {
			ip = ptr;
			return(1);
		}
	return(0);
}

/*
 * Registers
 */

struct	adsym	R8[] = {
    {	"b",	B|0400	},
    {	"c",	C|0400	},
    {	"d",	D|0400	},
    {	"e",	E|0400	},
    {	"h",	H|0400	},
    {	"l",	L|0400	},
    {	"a",	A|0400	},
    {	"",	0000	}
};

struct	adsym	R8X[] = {
    {	"i",	I|0400	},
    {	"r",	R|0400	},
    {	"ixh",	IXH|0400	},
    {	"ixl",	IXL|0400	},
    {	"iyh",	IYH|0400	},
    {	"iyl",	IYL|0400	},
    {	"mb",	MB|0400	},
    {	"",	0000	}
};

struct	adsym	RX[] = {
    {	"bc",	BC|0400	},
    {	"de",	DE|0400	},
    {	"hl",	HL|0400	},
    {	"sp",	SP|0400	},
    {	"ix",	IX|0400	},
    {	"iy",	IY|0400	},
    {	"",	0000	}
};

struct	adsym	RXX[] = {
    {	"af'",	AF|0400	},	/* af' must be first !!! */
    {	"af",	AF|0400	},
    {	"",	0000	}
};

/*
 * Conditional definitions
 */

struct	adsym	CND[] = {
    {	"NZ",	NZ|0400	},
    {	"Z",	Z |0400	},
    {	"NC",	NC|0400	},
    {	"C",	CS|0400	},
    {	"PO",	PO|0400	},
    {	"PE",	PE|0400	},
    {	"P",	P |0400	},
    {	"M",	M |0400	},
    {	"",	0000	}
};
