view lwasm/insn_tfm.c @ 402:b20f14edda5a

Completed initial conversion to new parser allowing spaces in operands Converted the remaining addressing modes. This required a complete rewrite of a large portion of the indexed addressing parser. Now the entire indexed parsing system is programmatic without cheating with a lookup table. This update also fixes the "force 0,r" by writing a literal 0,r which is *supposed* to work. There will likely be some pseudo ops that need tweaking for space handling, specially those that take multiple operands of some description which are not expressions. (The expression parser call eats the spaces both before and after the expression, if appropriate.)
author William Astle <lost@l-w.ca>
date Wed, 14 Oct 2015 20:49:41 -0600
parents 2abcd82b455f
children 01bdad2118aa
line wrap: on
line source

/*
insn_tfm.c
Copyright © 2009 William Astle

This file is part of LWASM.

LWASM 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/>.
*/

#include <ctype.h>
#include <string.h>

#include "lwasm.h"
#include "instab.h"

PARSEFUNC(insn_parse_tfm)
{
	static const char *reglist = "DXYUS   AB  00EF";
	int r0, r1;
	char *c;
	int tfm = 0;
			
	c = strchr(reglist, toupper(*(*p)++));
	if (!c)
	{
		lwasm_register_error(as, l, E_REGISTER_BAD);
		return;
	}
	r0 = c - reglist;
	if (**p == '+')
	{
		(*p)++;
		tfm = 1;
	}
	else if (**p == '-')
	{
		(*p)++;
		tfm = 2;
	}
	lwasm_skip_to_next_token(l, p);
	if (*(*p)++ != ',')
	{
		lwasm_register_error(as, l, E_UNKNOWN_OPERATION);
		return;
	}
	lwasm_skip_to_next_token(l, p);
	c = strchr(reglist, toupper(*(*p)++));
	if (!c)
	{
		lwasm_register_error(as, l, E_REGISTER_BAD);
		return;
	}
	r1 = c - reglist;

	if (**p == '+')
	{
		(*p)++;
		tfm |= 4;
	}
	else if (**p == '-')
	{
		(*p)++;
		tfm |= 8;
	}
	
	if (**p && !isspace(**p))
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	/* only D, X, Y, U, S are valid tfm registers */
	if (r0 > 4 || r1 > 4)
	{
		if (r0 < r1) r0 = r1;
		lwasm_register_error2(as, l, E_REGISTER_BAD, "'%c'", reglist[r0]);
	}

	// valid values of tfm here are:
	// 1: r0+,r1 (2)
	// 4: r0,r1+ (3)
	// 5: r0+,r1+ (0)
	// 10: r0-,r1- (1)
	switch (tfm)
	{
	case 5: //r0+,r1+
		l -> lint =  instab[l -> insn].ops[0];
		break;

	case 10: //r0-,r1-
		l -> lint = instab[l -> insn].ops[1];
		break;

	case 1: // r0+,r1
		l -> lint = instab[l -> insn].ops[2];
		break;

	case 4: // r0,r1+
		l -> lint = instab[l -> insn].ops[3];
		break;

	default:
		lwasm_register_error(as, l, E_UNKNOWN_OPERATION);
		return;
	}
	l -> pb = (r0 << 4) | r1;
	l -> len = OPLEN(l -> lint) + 1;
}

EMITFUNC(insn_emit_tfm)
{
	lwasm_emitop(l, l -> lint);
	lwasm_emit(l, l -> pb);
}

PARSEFUNC(insn_parse_tfmrtor)
{
	int r0, r1;
	static const char *regs = "D X Y U S       A B     0 0 E F ";
	
	// register to register (r0,r1)
	// registers are in order:
	// D,X,Y,U,S,PC,W,V
	// A,B,CC,DP,0,0,E,F
	r0 = lwasm_lookupreg2(regs, p);
	lwasm_skip_to_next_token(l, p);
	if (r0 < 0 || *(*p)++ != ',')
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		r0 = r1 = 0;
	}
	else
	{
		lwasm_skip_to_next_token(l, p);
		r1 = lwasm_lookupreg2(regs, p);
		if (r1 < 0)
		{
			lwasm_register_error(as, l, E_OPERAND_BAD);
			r0 = r1 = 0;
		}
	}
	l -> len = instab[l -> insn].ops[0] + 1;
	l -> pb = (r0 << 4) | r1;
}

EMITFUNC(insn_emit_tfmrtor)
{
	lwasm_emitop(l, instab[l -> insn].ops[0]);
	lwasm_emit(l, l -> pb);
}