view lwasm/insn_bitbit.c @ 393:f2decd9b276d

Fix minor error in string parsing Growing a buffer by 32 bytes and then only saying the buffer grew by one byte is not exactly efficient. While not strictly broken, it's dumb. Fix it to actually count the 32 bytes.
author William Astle <lost@l-w.ca>
date Tue, 14 Jul 2015 23:12:24 -0600
parents 8764142b3192
children b20f14edda5a
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;
	}
	
	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;
	}

	// 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);
}