Tons of fixes to the backtracker code, and also added an extra backtracker that does not require unwind tables to work and it is used if unwind tables are absent

Marlin/src/HAL/HAL_DUE/backtrace/unwarmbytab.h

@@ -0,0 +1,44 @@
+/***************************************************************************
+ * ARM Stack Unwinder, Michael.McTernan.2001@cs.bris.ac.uk
+ * Updated, adapted and several bug fixes on 2018 by Eduardo José Tagle
+ *
+ * This program is PUBLIC DOMAIN.
+ * This means that there is no copyright and anyone is able to take a copy
+ * for free and use it as they wish, with or without modifications, and in
+ * any context, commerically or otherwise. The only limitation is that I
+ * don't guarantee that the software is fit for any purpose or accept any
+ * liablity for it's use or misuse - this software is without warranty.
+ ***************************************************************************
+ * File Description: Interface to the memory tracking sub-system.
+ **************************************************************************/
+
+#ifndef UNWARMBYTAB_H
+#define UNWARMBYTAB_H
+
+#include "unwarm.h"
+
+typedef struct {
+  uint32_t vrs[16];
+  uint32_t current; /* Address of current byte */
+  int remaining;
+  int byte;
+} UnwTabState;
+
+typedef struct {
+  uint32_t addr_offset;
+  uint32_t insn;
+} UnwTabEntry;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+UnwResult UnwindByTableStart(UnwindFrame* frame, const UnwindCallbacks *cb, void *data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+/* END OF FILE */