1 files changed, 42 insertions, 0 deletions
diff --git a/ports/risc-v64/gnu/example_build/erbium/hwtimer.c b/ports/risc-v64/gnu/example_build/erbium/hwtimer.c
new file mode 100644
index 00000000..511bea59
--- /dev/null
+++ b/ports/risc-v64/gnu/example_build/erbium/hwtimer.c
@@ -0,0 +1,42 @@
+/***************************************************************************
+ * Copyright (c) 2026 Eclipse ThreadX contributors
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the MIT License which is available at
+ * https://opensource.org/licenses/MIT.
+ *
+ * AI Disclosure: This file was largely AI-generated by Claude Code (Opus 5.5).
+ * The AI-generated portions may be considered public domain (CC0-1.0)
+ * and not subject to the project's licence. The human contributor has
+ * reviewed and verified that the code is correct.
+ *
+ * SPDX-License-Identifier: MIT and CC0-1.0
+ **************************************************************************/
+
+#include "tx_api.h"
+#include "hwtimer.h"
+
+/* Naturally aligned 64-bit MMIO accesses are single loads and stores on
+   RV64; volatile keeps the compiler from caching or reordering them.  */
+#define MTIME                   (*(volatile uint64_t *)ERBIUM_MTIME)
+#define MTIMECMP                (*(volatile uint64_t *)ERBIUM_MTIMECMP)
+
+int hwtimer_init(void)
+{
+    MTIMECMP = MTIME + TICKNUM_PER_TIMER;
+    return 0;
+}
+
+int hwtimer_handler(void)
+{
+    /* Advance from the previous compare value, so trap latency does not
+       accumulate as tick drift.  */
+    uint64_t next = MTIMECMP + TICKNUM_PER_TIMER;
+    uint64_t now = MTIME;
+
+    if (next <= now)
+        next = now + TICKNUM_PER_TIMER;
+
+    MTIMECMP = next;
+    return 0;
+}