1 /* Copyright 2018 SiFive, Inc */
2 /* SPDX-License-Identifier: Apache-2.0 */
7 /* This macro enforces that the compiler will not elide the given access. */
8 #define __METAL_ACCESS_ONCE(x) (*(typeof(*x) volatile *)(x))
10 /* Allows users to specify arbitrary fences. */
11 #define __METAL_IO_FENCE(pred, succ) __asm__ volatile ("fence " #pred "," #succ ::: "memory");
13 /* Types that explicitly describe an address as being used for memory-mapped
14 * IO. These should only be accessed via __METAL_ACCESS_ONCE. */
15 typedef unsigned char __metal_io_u8;
16 typedef unsigned short __metal_io_u16;
17 typedef unsigned int __metal_io_u32;
18 #if __riscv_xlen >= 64
19 typedef unsigned long __metal_io_u64;