view lwasm/insn_bitbit.c @ 502:14a40f8bb4eb

Add various operators to lwcc Add various binary and ternary operators to lwcc, but only those which can work with constant operands. Seems like variables are probably required next.
author William Astle <lost@l-w.ca>
date Wed, 25 Sep 2019 20:23:49 -0600
parents b20f14edda5a
children
line wrap: on
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/*
insn_bitbit.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 <stdlib.h>
#include <ctype.h>

#include <lw_expr.h>

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

// these instructions cannot tolerate external references
PARSEFUNC(insn_parse_bitbit)
{
	int r;
	lw_expr_t e;
//	int v1;
//	int tv;

	r = toupper(*(*p)++);
	if (r == 'A')
		r = 1;
	else if (r == 'B')
		r = 2;
	else if (r == 'C' && toupper(**p) == 'C')
	{
		r = 0;
		(*p)++;
	}
	else
	{
		lwasm_register_error(as, l, E_REGISTER_BAD);
		return;
	}
	lwasm_skip_to_next_token(l, p);
	if (*(*p)++ != ',')
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 0, e);
	if (*(*p)++ != ',')
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}

	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 1, e);

	if (*(*p)++ != ',')
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_skip_to_next_token(l, p);
	// ignore base page address modifier
	if (**p == '<')
		(*p)++;
			
	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 2, e);

	l -> lint = r;
	l -> len = OPLEN(instab[l -> insn].ops[0]) + 2;
}

EMITFUNC(insn_emit_bitbit)
{
	int v1, v2;
	lw_expr_t e;
	
	e = lwasm_fetch_expr(l, 0);
	if (!lw_expr_istype(e, lw_expr_type_int))
	{
		lwasm_register_error(as, l, E_BITNUMBER_UNRESOLVED);
		return;
	}
	v1 = lw_expr_intval(e);
	if (v1 < 0 || v1 > 7)
	{
		lwasm_register_error(as, l, E_BITNUMBER_INVALID);
		v1 = 0;
	}

	e = lwasm_fetch_expr(l, 1);
	if (!lw_expr_istype(e, lw_expr_type_int))
	{
		lwasm_register_error(as, l, E_BITNUMBER_UNRESOLVED);
		return;
	}
	v2 = lw_expr_intval(e);
	if (v2 < 0 || v2 > 7)
	{
		lwasm_register_error(as, l, E_BITNUMBER_INVALID);
		v2 = 0;
	}
	l -> pb = (l -> lint << 6) | (v1 << 3) | v2;
	
	e = lwasm_fetch_expr(l, 2);
	if (lw_expr_istype(e, lw_expr_type_int))
	{
		v1 = lw_expr_intval(e) & 0xFFFF;
		v2 = v1 - ((l -> dpval) << 8);
		if (v2 > 0xFF || v2 < 0)
		{
			lwasm_register_error(as, l, E_BYTE_OVERFLOW);
			return;
		}
	}
	lwasm_emitop(l, instab[l -> insn].ops[0]);
	lwasm_emit(l, l -> pb);
	lwasm_emitexpr(l, e, 1);
}