/* z80adr.c */

/*
 *  Copyright (C) 1989-2014  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 "z80.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
 *	offset[REG]	S_IND+icode	----		offset		----
 */
int
addr(esp)
struct expr *esp;
{
	int c, mode, indx;

	if ((c = getnb()) == '#') {
		expr(esp, 0);
		esp->e_mode = S_IMMED;
	} else
	if (c == LFIND) {
		if ((indx = admode(R8)) != 0) {
			mode = S_INDB;
		} else
		if ((indx = admode(R16)) != 0) {
			mode = S_INDR;
		} else	
		if ((indx = admode(R8X)) != 0) {
			mode = S_R8X;
			aerr();
		} else
		if ((indx = admode(R16X)) != 0) {
			mode = S_R16X;
			aerr();
		} else {
			mode = S_INDM;
			expr(esp, 0);
			esp->e_mode = mode;
		}
		if (indx) {
			esp->e_mode = mode + (indx&0xFF);
			esp->e_base.e_ap = NULL;
		}
		if ((c = getnb()) != RTIND) {
			unget(c);
			if (indx && ((indx&0xFF)==IX || (indx&0xFF)==IY)) {
				expr(esp, 0);
				esp->e_mode = S_INDR + (indx&0xFF);
			}
			if ((c = getnb()) != RTIND)
				qerr();
		}
	} else {
		unget(c);
		if ((indx = admode(R8)) != 0) {
			mode = S_R8;
		} else
		if ((indx = admode(R16)) != 0) {
			mode = S_R16;
		} else	
		if ((indx = admode(R8X)) != 0) {
			mode = S_R8X;
		} else
		if ((indx = admode(R16X)) != 0) {
			mode = S_R16X;
		} else {
			mode = S_USER;
			expr(esp, 0);
			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) {
			if ((indx=admode(R16))!=0
				&& ((indx&0xFF)==IX || (indx&0xFF)==IY)) {
				esp->e_mode = S_INDR + (indx&0xFF);
			} else {
				aerr();
			}
			if ((c = getnb()) != RTIND)
				qerr();
		} else {
			unget(c);
		}
	}
	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)
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 (!(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	},
    {	"",	0000	}
};

struct	adsym	R16[] = {
    {	"bc",	BC|0400	},
    {	"de",	DE|0400	},
    {	"hl",	HL|0400	},
    {	"sp",	SP|0400	},
    {	"ix",	IX|0400	},
    {	"iy",	IY|0400	},
    {	"",	0000	}
};

struct	adsym	R16X[] = {
    {	"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	}
};
