|*****************************************************************************
|
|   NAME
|
|	__AROS_LH0(void, Disable,
|
|   LOCATION
|	struct ExecBase *, SysBase, 20, Exec)
|
|   FUNCTION
|	This function disables the delivery of all interrupts until a matching
|	call to Enable() is done. This implies a Forbid(). Since the system
|	needs the regular delivery of all interrupts it's forbidden to disable
|	them for longer than ~250 microseconds.
|
|	THIS CALL IS VERY DANGEROUS!!!
|
|	Do not use it without thinking very well about it or better don't use
|	it at all. Most of the time you can live without it by using semaphores
|	or similar.
|
|	Calls to Disable() nest, i.e. for each call to Disable() you need one
|	call to Enable().
|
|   INPUTS
|
|   RESULT
|
|   NOTES
|	This function preserves all registers.
|
|	This function may be used from interrupts to disable all higher
|	priority interrupts. Lower priority interrupts are disabled anyway.
|
|	To prevent deadlocks calling Wait() in disabled state breaks the
|	disable - thus interrupts and taskswitches may happen again.
|
|   EXAMPLE
|
|   BUGS
|
|   SEE ALSO
|	Forbid(), Permit(), Enable(), Wait()
|
|   INTERNALS
|	For old exec Disable() there exists an assembler macro replacement
|	that is (of course) importable. Using a Disable() implementation
|	equal to this macro would not only have some impact on Disable()
|	itself but also on other functions (e.g. Signal()).
|	Therefore I decided to drop support for this macro to a certain
|	extend. The difference is only miniscule:
|	If a task uses the assembler macro and activates some higher priority
|	task he cannot expect this task to be awakened immediately at Enable()
|	but only at the next context switch. But I don't think that this
|	poses any problems.
|
|   HISTORY
|
|******************************************************************************

	IDNestCnt   =	0x126
	INTENA	    =	0xdff09a
	INTEN	    =	0x4000
	SET	    =	0x8000

	.globl	_Exec_Disable
_Exec_Disable:
	| disable interrupts
	movew	#INTEN,INTENA

	| increment nesting count and return
	addqb	#1,a6@(IDNestCnt)
	rts