32 lines
1.0 KiB
C
32 lines
1.0 KiB
C
#ifndef _MEMORY_BARRIER_H_
|
|
#define _MEMORY_BARRIER_H_
|
|
|
|
#include <util/atomic.h>
|
|
#include <avr/version.h>
|
|
|
|
// Provide a memory barrier to the compiler. This informs
|
|
// the compiler that is should write any cached values that
|
|
// are destined for a global variable and discard any other
|
|
// cached values from global variables.
|
|
//
|
|
// Note that this behavior does apply to all global variables,
|
|
// not just volatile ones. However, cached local variables
|
|
// are not affected as they are not externally visible.
|
|
|
|
#define MEMORY_BARRIER() __asm volatile( "" ::: "memory" )
|
|
|
|
// There is a bug in the CLI/SEI functions in older versions of
|
|
// avr-libc - they should be defined to include a memory barrier.
|
|
// This macro is used to define the barrier in the code so that
|
|
// it will be easy to remove once the bug has become ancient history.
|
|
// At the moment the bug is included in most of the distributed
|
|
// compilers.
|
|
|
|
#if __AVR_LIBC_VERSION__ < 10700UL
|
|
#define CLI_SEI_BUG_MEMORY_BARRIER() MEMORY_BARRIER()
|
|
#else
|
|
#define CLI_SEI_BUG_MEMORY_BARRIER()
|
|
#endif
|
|
|
|
#endif
|