1 files changed, 83 insertions, 0 deletions
diff --git a/lib_m68k/extable.c b/lib_m68k/extable.c
new file mode 100644
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--- /dev/null
+++ b/lib_m68k/extable.c
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+/*
+ * Copyright (C) 1999  Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
+ *
+ * (C) Copyright 2000
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+
+/*
+ * The exception table consists of pairs of addresses: the first is the
+ * address of an instruction that is allowed to fault, and the second is
+ * the address at which the program should continue.  No registers are
+ * modified, so it is entirely up to the continuation code to figure out
+ * what to do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path.  This means when everything is well,
+ * we don't even have to jump over them.  Further, they do not intrude
+ * on our cache or tlb entries.
+ */
+
+struct exception_table_entry {
+	unsigned long insn, fixup;
+};
+
+extern const struct exception_table_entry __start___ex_table[];
+extern const struct exception_table_entry __stop___ex_table[];
+
+static inline unsigned long
+search_one_table (const struct exception_table_entry *first,
+		  const struct exception_table_entry *last,
+		  unsigned long value)
+{
+	while (first <= last) {
+		const struct exception_table_entry *mid;
+		long diff;
+
+		mid = (last - first) / 2 + first;
+		diff = mid->insn - value;
+		if (diff == 0)
+			return mid->fixup;
+		else if (diff < 0)
+			first = mid + 1;
+		else
+			last = mid - 1;
+	}
+	return 0;
+}
+
+int ex_tab_message = 1;
+
+unsigned long search_exception_table (unsigned long addr)
+{
+	unsigned long ret;
+
+	/* There is only the kernel to search.  */
+	ret = search_one_table (__start___ex_table, __stop___ex_table - 1,
+				addr);
+	if (ex_tab_message)
+		printf ("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
+	if (ret)
+		return ret;
+
+	return 0;
+}