Import Mbed OS hard-float snapshot

targets/TARGET_NUVOTON/nu_timer.c

@@ -0,0 +1,67 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2015-2016 Nuvoton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nu_timer.h"
+#include "mbed_power_mgmt.h"
+#include "mbed_critical.h"
+#include "us_ticker_api.h"
+#include "mbed_assert.h"
+
+void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us)
+{
+    core_util_critical_section_enter();
+    sleep_manager_lock_deep_sleep();
+    ctx->_ticker_data = get_us_ticker_data();
+    ctx->_interval_end_us = ticker_read_us(ctx->_ticker_data) + interval_us;
+    ctx->_expired = false;
+    core_util_critical_section_exit();
+}
+
+bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx)
+{
+    core_util_critical_section_enter();
+    if (! ctx->_expired) {
+        ctx->_expired = ticker_read_us(ctx->_ticker_data) >= ctx->_interval_end_us;
+    }
+    core_util_critical_section_exit();
+    
+    return ctx->_expired;
+}
+
+void nu_countdown_free(struct nu_countdown_ctx_s *ctx)
+{
+    core_util_critical_section_enter();
+    sleep_manager_unlock_deep_sleep();
+    core_util_critical_section_exit();
+}
+
+
+void nu_busy_wait_us(uint32_t us)
+{
+    const uint32_t bits = us_ticker_get_info()->bits;
+    const uint32_t mask = (1 << bits) - 1;
+    MBED_ASSERT(us_ticker_get_info()->frequency == 1000000);
+    uint32_t prev = us_ticker_read();
+    while (1) {
+        const uint32_t cur = us_ticker_read();
+        const uint32_t elapsed = (cur - prev) & mask;
+        if (elapsed > us) {
+            break;
+        }
+        us -= elapsed;
+        prev = cur;
+    }
+}