Merge pull request #191 from sifive/esat-25

Add macro & inline for get/set CSR

Makefile.am

@@ -87,6 +87,7 @@ nobase_include_HEADERS = \
 	metal/clock.h \
 	metal/compiler.h \
 	metal/cpu.h \
+	metal/csr.h \
 	metal/gpio.h \
 	metal/init.h \
 	metal/interrupt.h \

metal/csr.h

@@ -0,0 +1,32 @@
+/* Copyright 2019 SiFive, Inc */
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#ifndef METAL__CSR_H
+#define METAL__CSR_H
+
+#include <metal/compiler.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/*!
+ * @file csr.h
+ * @brief A collection of APIs for get and set CSR registers
+ */
+
+/*!
+ * @brief Read a given CSR register without checking validity of CSR offset
+ * @param crs Register label or hex value offset to read from
+ * @param value Variable name of uintprt_t type to get the value
+ */
+#define METAL_CPU_GET_CSR(reg, value)                                          \
+    __asm__ volatile("csrr %0, " #reg : "=r"(value));
+
+/*!
+ * @brief Write to a given CSR register without checking validity of CSR offset
+ * @param crs Register label or hex value offset to write to
+ * @param value Variable name of uintprt_t type to set the value
+ */
+#define METAL_CPU_SET_CSR(reg, value)                                          \
+    __asm__ volatile("csrw " #reg ", %0" : : "r"(value));
+
+#endif // METAL__CSR_H