.TITLE	MR10.. STRING PROCEDURES IN MACRO
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	.IDENT	/MR10../
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	.PAGE
	.SBTTL	.		CHARACTER SHIFT ONE PLACE RIGHT/LEFT
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R$SHR::					;SHIFT CHARACTER STRING ONE PLACE RIGHT
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;		ENTRY CONDITIONS
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;		R0 -> CHARACTER STRING ADDRESS
;		R3 =  FILLER CHARACTER
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	CALL	R$SAVE 			;SAVE REGISTERS R0 TO R5
	CALL R$SHRE			;SHIFT STRING ONE PLACE RIGHT END AROUND
	MOV R0,R4			;HOLD STRING ADDRESS
	MOV R0,R1
	MOV #1,R2			;START POSITION IN STRING
	CALL R$GETC			;R0 HOLDS FIRST CHARACTER IN STRING
	CALL R$ADDC			;PLACE COPY OF FIRST CHARACTER AT THE
					;OF MODIFIED STRING
	MOV R3,R0			;TAKE COPY OF FILLER CHARACTER
	CALL R$MODC			;OVERWRITE FIRST CHARACTER WITH FILLER
	CALL	R$UNSAVE 		;RESTORE REGISTERS R0 TO R5
	RETURN				;EXIT
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R$SHL::				;SHIFT CHARACTER STRING ONE PLACE LEFT
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;		ENTRY CONDITIONS
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;		R0 -> CHARACTER STRING ADDRESS
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	TST @R0			;IS STRING LENGTH <=0
	BLE	10$		;J IF STRING EMPTY
	CALL R$SHRE		;ROTATE STRING ONE PLACE RIGHT END AROUND
	DEC @R0			;REDUCE STRING LENGTH BY ONE CHARACTER
10$:	RETURN			;EXIT
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	.END
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