.TITLE	MR21.. STRING PROCEDURES IN MACRO
	.IDENT	/MR21../
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	.SBTTL	NUMERIC TIDY PROCEDURE
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R$NTDY::			;PROCEDURE TO TIDY A NUMERIC STRING
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;		ENTRY POINTS
;	(+0)	REMOVE LEADING ZEROS AND SIGN IF IT IS A PLUS
;	(+2)	CONVERT LEADING ZEROS TO SPACES
;	(+4)	REMOVE SIGN CHARACTER IF IT IS A PLUS
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;		ENTRY CONDITIONS
;		R0 -> NUMERIC STRING
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;		EXIT CONDITIONS
;		R0 -> TIDIED NUMERIC STRING
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	BR	10$		;ENTRY +0
	BR	20$		;ENTRY +2
	BR	30$		;ENTRY +4
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10$:	SAVE R1,R2		;SAVE REGISTERS
	MOV R0,R1		;HOLD STRING ADDRESS
	MOV #2,R2		;POSITION OF FIRST POSSIBLE LEADING ZERO
12$:	CMP @R1,R2		;HAS STRING BEEN REDUCED TO ONE NUMERIC
	BLE	14$		;J IF ONLY SIGN AN ONE NUMERIC
	CMPB 3(R1),#'0		;IS THIS A LEADING ZERO
	BNE	14$		;J IF NOT LEADING ZERO
	CALL R$DELC		;DELETE LEADING ZERO CHARACTER
	BR	12$		;LOOP TILL TIDY STRING
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14$:	CALL	30$		;REMOVE PLUS SIGN
	BR	60$		;EXIT
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20$:	SAVE R1,R2		;PROTECT REGISTERS
	MOV R0,R2		;HOLD STRING ADDRESS
	ADD #3,R2		;HOLD ADDRESS OF FIRST CHARACTER
	MOV @R0,R1		;LOOP COUNTER (LENGTH OF STRING)
	DEC R1			;REMOVE ONE CHAR FOR CORRECT COUNT
;
22$:	CMP @R2,#'0		;IS THIS A LEADING ZERO
	BNE	24$		;J IF NOT
	MOVB #40,(R2)+		;REPLACE ZERO WITH A SPACE
	SOB R1,22$		;PROCESS UP TO 4 CHARACTERS
24$:	BR	60$		;EXIT
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30$:	CMPB 2(R0),#'+		;IS THIS A POSITIVE VALUE
	BNE	32$		;J IF NO A POSITIVE VALUE
	CALL R$SHL		;DELETE PLUS SIGN BY SHIFTING STRING
				;ONE PLACE LEFT
32$:	RETURN			;GO BACK TO CALLING PROGRAM
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60$:	UNSAVE	R1,R2		;RESTORE ALL USED REGISTERS
	RETURN			;GO BACK HOME
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	.END
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