.TITLE	CASE	COMPUTED SUBROUTINE CALL
	.SBTTL	GENERAL INFORMATION
	.IDENT	/01/
	.LIST	ME

;+
; AUTHOR:	KERRY WYCKOFF
;-
 
;+
; CHANGES:	NONE
;-
 
;+
; MODULE FUNCTION:
;
;	THIS ROUTINE USES THE SPECIFIED INDEX
;	TO CALL THE CORRESPONDING SUBROUTINE IN THE
;	PARAMETER LIST. IF THERE IS NO SUCH SUBROUTINE,
;	THE ROUTINE SIMPLY RETURNS.
;
;-
 
;+
; ASSEMBLY INSTRUCTIONS:
;
;	MAC CASE=CASE
;
;-

;+
; CALL FORMAT:
;
;	CALL CASE(INDEX,SUB1,...,SUBN)
;
;-

	.PAGE
	.SBTTL	SYMBOL, MACRO, DATA DEFINITIONS

;+
; LOCAL SYMBOL DEFINITIONS:	NONE
;-
 
;+
; LOCAL MACROS:	NONE
;-
 
;+
; LOCAL DATA BLOCKS:	NONE
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	.PAGE
	.SBTTL	FUNCTION DETAILS

;+
; FUNCTION DETAILS:
;
;
;	INPUTS:
;
;		R5 CONTAINS THE ADDRESS OF THE PARAMETER LIST
;		1) WORD: NUMBER OF PARAMETERS
;		2) WORD: ADDRESS OF INDEX
;		3) WORD: ADDRESS OF SUBROUTINE 1
;		.
;		.
;		.
;	      N+2) WORD: ADDRESS OF N TH SUBROUTINE
;
;	OUTPUTS:	NONE
;
;	SIDE EFFECTS:
;
;		R5 HAS BEEN ALTERED TO INCREASE SPEED
;
;-
 
 
	.PAGE
	.SBTTL	CODE SECTION
	.PSECT	W12COD
	.ENABL	LSB
CASE::
	MOV	@2(R5),R0		; R0=INDEX
	BLE	99$			; IF LE 0, RETURN
	CMP	(R5)+,R0		; ENOUGH ROUTINES ?
	BGE	99$			; IF NOT, RETURN
	ADD	R0,R0			; DOUBLE FOR WORDS
	ADD	R5,R0			; R0=ADDRESS OF ADDRESS
	MOV	(R0),PC			; SUBROUTINE ADDRESS TO PC
99$:
	RTS	PC			; RETURN
	.END