/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. See the file COPYING
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Copyright (C) 2010 Frank van Maarseveen <frankvm@frankvm.com>
 */

/*
 * sei(), cli() and accessing SREG directly is fscked up by gcc by reordering across it.
 * Note that sei() never interrupts the instruction following it. Since saveicli() issues
 * at least one instruction before cli() it is possible to restore interrupt state
 * temporarily without do_nop() in between by:
 *
 *	restorei(sreg);
 *	saveicli(sreg);
 *
 */
#define saveicli(x)	do { x = SREG; __asm__ __volatile__ ("cli" ::: "memory"); } while (0)
#define restorei(x)	do { __asm__ __volatile__ ("" ::: "memory"); SREG = x; } while (0)
#define do_sei()	do { __asm__ __volatile__ ("sei" ::: "memory"); } while (0)
#define do_wdr()	do { __asm__ __volatile__ ("wdr" ::: "memory"); } while (0)
#define do_nop()	do { __asm__ __volatile__ ("nop" ::: "memory"); } while (0)
#define do_sleep()	do { __asm__ __volatile__ ("sleep" ::: "memory"); } while (0)
#define barrier()	do { __asm__ __volatile__ ("" ::: "memory"); } while (0)

/*
 * Newer gccs have this builtin for telling the compiler code cannot be reached.
 * Useful for suppressing a "'noreturn' function does return" warning.
 */
__attribute__((always_inline,noreturn))
static inline void __builtin_unreachable(void)
{
	while (1)
		;
}

#define ARRAYSIZE(x)	(sizeof (x) / sizeof ((x)[0]))