.title	get_number_of_args - get caller's number of args
	.ident	"V1.0-0"

	;++
	;
	; Functional description:
	; 
	;
	;	This routine get the number of arguments passed to the routine
	; whitch call it. Previous AP is found using Call Frame (pointed by FP).
	; The call stack frame, described in "VAX Architecture Reference
	; Manual", page 89, look like this :
	;
	;	+-------------------------------+
	;	|Condition handler (initially 0)|	<---- FP
	;	+---+-+-+-------+-+---------+---+
	;	|SPA|S|0|  Mask	|Z|saved PSW| 0 |
	;	+---+-+-+-------+-+---------+---+
	;	|	     Saved AP		|	<---- Caller's AP
	;	+-------------------------------+
	;	|	     Saved FP		|
	;	+-------------------------------+
	;	|	     Saved PC		|
	;	+-------------------------------+
	;	|Saved R0 (if specified in mask)|
	;	+-------------------------------+
	;	|Saved R1 (if specified in mask)|
	;	+-------------------------------+
	;	|		.		|
	;			.
	;	|		.		|
	;	+-------------------------------+
	;	|    Saved R11 (if specified)   |
	;	+-------------------------------+
	;	Here 0 to 3 bytes specified by SPA
	;
	; 
	; Calling sequence:
	; 
	;	call get_number_of_args (number_of_args)
	; 
	; Input parameters:
	; 
	;	None
	;
	; Implicit inputs:
	;
	;	Use FP to locate caller's AP value.
	; 
	; Output parameters:
	; 
	;	Number_of_args : contains the number of args passed to the
	;				callers.
	;		Type : unsigned longword
	;		Access : write only
	;		Mechanism : by reference
	; 
	; Implicit outputs:
	; 
	;	None
	; 
	; Completion codes:
	; 
	;	R0 always contains SS$_NORMAL
	; 
	; Side effects:
	; 
	;	None
	; 
	; Modification history :
	;
	;	V1.0-0	17-Apr-1991	Francois FOUCHET
	;		Initial creation
	;
	;--

	.psect	_code,exe,nowrt,shr,pic,long
	.entry	get_number_of_args,^m<>
	movzwl	@8(fp),@4(ap)			; Get previous AP
	movzwl	#ss$_normal,r0			; Set success
	ret					; See you ..

	.end