esp_rom: Add initial ESP32-C3 support

From internal commit 7761d6e8

components/esp_rom/include/esp32c3/rom/bigint.h

@@ -0,0 +1,43 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+#ifndef _ROM_BIGINT_H_
+#define _ROM_BIGINT_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ets_bigint_enable(void);
+
+void ets_bigint_disable(void);
+
+int ets_bigint_multiply(const uint32_t *x, const uint32_t *y, uint32_t len_words);
+
+int ets_bigint_modmult(const uint32_t *x, const uint32_t *y, const uint32_t *m, uint32_t m_dash, const uint32_t *rb, uint32_t len_words);
+
+int ets_bigint_modexp(const uint32_t *x, const uint32_t *y, const uint32_t *m, uint32_t m_dash, const uint32_t *rb, bool constant_time, uint32_t len_words);
+
+void ets_bigint_wait_finish(void);
+
+int ets_bigint_getz(uint32_t *z, uint32_t len_words);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _ROM_BIGINT_H_ */