csnum fix

runtime/include/sc_serial_contract.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <charconv>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+#include <system_error>
+
+namespace RuntimeScSerial {
+
+// SCGetProductSN's output is a u32, not a character buffer. DWC loads
+// that word and formats it with the product code to construct csnum.
+template <typename RangeValidator, typename WordWriter>
+uint32_t Write(std::string_view serial, uint32_t address,
+               RangeValidator&& contains, WordWriter&& write32) {
+    if (serial.empty() || serial.size() > 9 ||
+        serial.find_first_not_of("0123456789") != std::string_view::npos) return 0;
+    uint32_t number = 0;
+    const auto parsed = std::from_chars(serial.data(), serial.data() + serial.size(), number);
+    if (parsed.ec != std::errc{} || parsed.ptr != serial.data() + serial.size() ||
+        !address || !contains(address, sizeof(uint32_t))) return 0;
+    write32(address, number);
+    return 1;
+}
+
+} // namespace RuntimeScSerial