diff src/insn_rel.c @ 29:37aec845aef3

Added relative addressing handler
author lost
date Fri, 02 Jan 2009 03:27:33 +0000
parents
children 9bd0fbfe7405
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/insn_rel.c	Fri Jan 02 03:27:33 2009 +0000
@@ -0,0 +1,80 @@
+/*
+insn_rel.c
+Copyright © 2008 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/>.
+*/
+
+/*
+for handling relative mode instructions
+*/
+
+#define __insn_inh_c_seen__
+
+#include <stdlib.h>
+
+#include "expr.h"
+#include "lwasm.h"
+#include "instab.h"
+
+OPFUNC(insn_rel8)
+{
+	lwasm_expr_stack_t *s;
+	int v;
+	
+	lwasm_emitop(as, l, instab[opnum].ops[0]);
+	
+	s = lwasm_expr_eval(*p, NULL);
+	if (!s)
+	{
+		register_error(as, l, 1, "Bad operand");
+		lwasm_emitop(as, l, 0);
+		return;
+	}
+	if (lwasm_expr_is_constant(s))
+		register_error(as, l, 2, "Incomplete reference");
+	v = lwasm_expr_get_value(s);
+	v -= as -> addr + 1;
+	if (v < -128 || v > 127)
+		register_error(as, l, 2, "Byte overflow");
+	lwasm_emit(as, l, v & 0xff);
+	
+	lwasm_expr_stack_free(s);
+}
+
+OPFUNC(insn_rel16)
+{
+	lwasm_expr_stack_t *s;
+	int v;
+	
+	lwasm_emitop(as, l, instab[opnum].ops[0]);
+	
+	s = lwasm_expr_eval(*p, NULL);
+	if (!s)
+	{
+		register_error(as, l, 1, "Bad operand");
+		lwasm_emitop(as, l, 0);
+		return;
+	}
+	if (lwasm_expr_is_constant(s))
+		register_error(as, l, 2, "Incomplete reference");
+	v = lwasm_expr_get_value(s);
+	v -= as -> addr + 2;
+	lwasm_emit(as, l, (v >> 8) & 0xff);
+	lwasm_emit(as, l, v & 0xff);
+	
+	lwasm_expr_stack_free(s);
+}