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Trailing-Edge - PDP-10 Archives - BB-H580C-SB_1981 - ebcasc.mac
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TITLE	EBCASC	EBCDIC TO ASCII CONVERSION TABLE.
SUBTTL	/ACK



;THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY ONLY BE USED
;  OR COPIED IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.
;
;COPYRIGHT (C) 1975, 1981 BY DIGITAL EQUIPMENT CORPORATION

	SEARCH	P
	%%P==:%%P
	DEBUG==:DEBUG

	SEARCH	CHREQV		;DEFINE THE CHARACTER EQUIVALENCES.

;EDITS:
;V10********************
;NAME	DATE		COMMENTS
;ACK	22-APR-75	CREATION.
;***********************

	HISEG
	SALL
	.XCREF

	ENTRY	EBASC.
COMMENT	\

	THIS MODULE CONTAINS THE CONVERSION TABLE FOR CONVERTING EBCDIC
CHARACTERS TO ASCII.

THE TABLE IS STRUCTURD AS FOLLOWS:

	WORD EBASC.+N CONTAINS:

	IN BITS			THE EBCDIC CHARACTER EQUIVALENT TO THE
				ASCII CHARACTER WHOSE VALUE IS

	0-8				N*4
	9-17				N*4+1
	18-26				N*4+2
	27-35				N*4+3

	GIVEN AN EBCDIC CHARACTER IN TAC1 THE FOLLOWING CODE COULD BE
USED TO CONVERT IT TO ASCII:

	ROT	TAC1,	-2
	JUMPL	TAC1,	.+3
	HLR	TAC1,	EBASC.##(TAC1)
	CAIA
	HRL	TAC1,	EBASC.##(TAC1)
	TLNN	TAC1,	(1B1)
	LSH	TAC1,	-^D9

\
;MACROS USED TO GENERATE THE TABLE.

	DEFINE	X0	(I)<
	I0=I
	I1==I+1
	I2==I+2
	I3==I+3

	X1	\I0,\I1,\I2,\I3

>	;END OF DEFINITION OF X0.


	DEFINE	X1	(I0,I1,I2,I3)<BYTE	(9)EA%'I0,EA%'I1,EA%'I2,EA%'I3>


	DEFINE	TBLGEN<
	IFE	DEBUG,<XLIST>		;;DON'T LIST THE TABLE UNLESS WE
					;; ARE DEBUGGING IT.
	I==0
	REPEAT	100,<
		X0	I
		I==I+4
>	;END OF REPEAT 40.
	LIST
>	;END OF DEFINITION OF TBLGEN.

;GENERATE THE TABLE.

	.CREF
EBASC.:	BLOCK	0
	.XCREF

	TBLGEN

	END