arc: libgloss: Introduce hostlink interface

There is a special interface built in ARC simulators (such as
nSIM) called MetaWare hostlink IO which can be used to implement
system calls. This commit adds support for this interface to the
ARC port of libgloss.

Here is an example of using this interface:

    $ arc-elf32-gcc -mcpu=hs -specs=hl.specs main.c -o main
    $ nsimdrv -tcf $NSIM_HOME/etc/tcf/templates/hs48_full.tcf main
    Hello, World!

Signed-off-by: Vladimir Isaev <vvisaev@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/libgloss/arc/hl-setup.c b/libgloss/arc/hl-setup.c
new file mode 100644
index 0000000..a8affbc
--- /dev/null
+++ b/libgloss/arc/hl-setup.c
@@ -0,0 +1,27 @@
+/*
+ * hl-setup.c -- provide _setup_low_level() to initialize timer.
+ *
+ * Copyright (c) 2024 Synopsys Inc.
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ *
+ */
+
+#include "arc-timer.h"
+
+/* Configure and reset the default timer.  */
+int
+_setup_low_level (void)
+{
+  _arc_timer_default_reset ();
+
+  return 0;
+}