add gap8 board of riscv for xiuos

Ubiquitous/XiUOS/arch/risc-v/gap8/tick.c

@@ -0,0 +1,19 @@
+/*
+* Copyright (c) 2020 AIIT XUOS Lab
+* XiUOS is licensed under Mulan PSL v2.
+* You can use this software according to the terms and conditions of the Mulan PSL v2.
+* You may obtain a copy of Mulan PSL v2 at:
+*        http://license.coscl.org.cn/MulanPSL2
+* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+* See the Mulan PSL v2 for more details.
+*/
+#include <xs_ktick.h>
+static volatile unsigned long tick_cycles = 0;
+int TickIsr(void)
+{
+    TickAndTaskTimesliceUpdate();
+
+    return 0;
+}