Add support for ATOMIC_BLOCK

[V10git]

My code uses avr-gcc util\atomic.h. For code block should be executed with disabled irqs and restore irqs state(disable, enable) after code block ends.
Example:

ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
// some long time executed code irqs free
}

Can you add correct support of this to core?
In my code I use this workaround(not tested):

#ifdef __ARM__
	#ifndef ATOMIC_BLOCK
		#define ATOMIC_BLOCK(type) for ( type, __ToDo = __iCliRetVal(); \
								__ToDo ; __ToDo = 0 )
		#define ATOMIC_RESTORESTATE uint8_t __primask_save \
			__attribute__((__cleanup__(__iRestore))) = __get_PRIMASK()

		static __inline__ uint8_t __iCliRetVal(void)
		{
			__disable_irq();
			return 1;
		}
		static __inline__ void __iRestore(const  uint8_t *__s)
		{
			__set_PRIMASK(*__s);
			__asm__ volatile ("" ::: "memory");
		}
	#endif
#endif

[V10git]

This definition should correct work for code like this:

void someFunc()
{
   ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
      // some long time executed code irqs free
   } // irqs state not changed
}

void someFunc2()
{
   // irq disabled
   ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
      someFunc();
      // some long time executed code irqs free
   }  // irq enabled
}