.MCALL	.MODULE
.MODULE	PC,VERSION=05,COMMENT=<Paper Tape Handler>,AUDIT=YES

;                     	COPYRIGHT (c) 1986 BY
;             DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.
;                         ALL RIGHTS RESERVED.
;
; THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND  COPIED
; ONLY  IN  ACCORDANCE  WITH  THE  TERMS  OF  SUCH  LICENSE AND WITH THE
; INCLUSION OF THE ABOVE COPYRIGHT NOTICE.  THIS SOFTWARE OR  ANY  OTHER
; COPIES  THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
; OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF  THE  SOFTWARE  IS  HEREBY
; TRANSFERRED.
;
; THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE  WITHOUT  NOTICE
; AND  SHOULD  NOT  BE  CONSTRUED  AS  A COMMITMENT BY DIGITAL EQUIPMENT
; CORPORATION.
;
; DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR  RELIABILITY  OF  ITS
; SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.

.SBTTL	CONDITIONAL ASSEMBLY SUMMARY
;+
;COND
;
;	PR11$X	(0)		support both reader and punch
;	PR11$X	0		support both reader and punch
;	PR11$X	1		support only reader
;
;	PP$CSR	(PC$CSR+4)	punch CSR
;	PP$VEC	(PC$VEC+4)	punch vector
;
;	MMG$T			std conditional
;	TIM$IT			std conditional (no code effects)
;	ERL$G			std conditional (no code effects)
;-

.SBTTL	EDIT HISTORY

; DL02 - FIX NON-STANDARD VECTOR ADDRESS ASSIGNMENT STATEMENT
;
; 03	4-Aug-85 Jim Williams
;	add .DRPTR, .DREST

.SBTTL	MACROS AND DEFINITIONS

.MCALL	.DRDEF

.IIF NDF PR11$X, PR11$X=0	;UNLESS SPECIFIED, DO NOT GENERATE READER ONLY
.IIF NE PR11$X, PR11$X=1	;FORCE NON-ZERO VALUE TO 1

.DRDEF	PC,7,<PR11$X*RONLY$>,0,177550,70
.DRPTR
.DREST	CLASS=DVC.UK

PCB	== PC$CSR+2			;DATA REGISTER

; PAPER TAPE PUNCH CONTROL REGISTERS
.IIF NDF PP$VEC, PP$VEC == PC$VEC+4	;PUNCH VECTOR ADDR
.IIF NDF PP$CSR, PP$CSR == PC$CSR+4	;PUNCH CONTROL REGISTER
PPB	= PP$CSR+2		;PUNCH DATA BUFFER

PRGO	= 1			;READER ENABLE BIT
PINT	= 101			;INTERRUPT ENABLE BIT AND GO BIT

	.SBTTL	DRIVER ENTRY

	.DRBEG	PC		;DEFINE ENTRY POINT AND QUEUE HEADS
	MOV	PCCQE,R4	;POINT TO CURRENT QUEUE ELEMENT
	ASL	Q$WCNT(R4)	;CONVERT WORD COUNT TO BYTE COUNT
	BCS	PP		;IF NEGATIVE, PUNCH (OR ERROR IN NO PUNCH)
	BEQ	PCDONE		;A REQUEST FOR 0 BYTES IS A SEEK, JUST EXIT
	MOV	#PC$CSR,R5	;READ REQUEST, GET THE CSR
	TST	(R5)+		;IS READER READY?
	BPL	PCGORD		;YES, START TRANSFER
	BIS	#EOF$,@-(R4)	;NOT READY ON ENTRY, SET EOF
	BR	PCFIN		; AND COMPLETE OPERATION

; START PUNCH OPERATION (IMMEDIATE ERROR IF NO PUNCH SUPPORT)

PP:
.IF EQ	PR11$X
	BIS	#100,@#PP$CSR	;CAUSES INTERRUPT, STARTING TRANSFER
	RTS	PC

; PUNCH-READER VECTOR TABLE

	.DRVTB	PC,PC$VEC,PCINT
	.DRVTB	,PP$VEC,PPINT

; PUNCH INTERRUPT SERVICE

	.DRAST	PP,4,PCDONE
	MOV	PCCQE,R4	;POINT TO CURRENT QUEUE ELEMENT
	MOV	#PP$CSR,R5	;POINT TO PUNCH STATUS REGISTER
	TST	(R5)+		;ERROR?
	BMI	PPERR		;YES, PUNCH OUT OF PAPER
.IF EQ	MMG$T
	ADD	#Q$WCNT,R4	;POINT TO WORD COUNT
	TST	@R4		;ANY MORE CHARACTERS TO OUTPUT?
	BEQ	PCDONE		;NO, TRANSFER DONE
	INC	@R4		;DECREMENT BYTE COUNT (IT IS NEGATIVE)
	MOVB	@-(R4),@R5	;PUNCH CHARACTER
	INC	@R4		;BUMP POINTER
.IFF
	TST	Q$WCNT(R4)	;ANY MORE CHARACTERS TO OUTPUT?
	BEQ	PCDONE		;NO, TRANSFER DONE
	INC	Q$WCNT(R4)	;DECREMENT BYTE COUNT (IT IS NEGATIVE)
	JSR	PC,@$GTBYT	;GET A BYTE FROM USER BUFFER
	MOVB	(SP)+,@R5	;PUNCH IT
.ENDC ;EQ MMG$T
	RTS	PC

.ENDC ;EQ PR11$X

PPERR:	BIS	#HDERR$,@-(R4)	;SET HARD ERROR BIT
	BR	PCFIN		;GO TO I/O COMPLETION

; READER INTERRUPT SERVICE

	.DRAST	PC,4,PCDONE
	MOV	PCCQE,R4	;POINT TO CURRENT QUEUE ELEMENT
.IF EQ	MMG$T
	ADD	#Q$WCNT,R4	; AT WORD COUNT
.ENDC ;EQ MMG$T
	MOV	#PC$CSR,R5	;POINT TO READER STATUS REGISTER
	TST	(R5)+		;ANY ERRORS?
	BMI	PREOF		;YES, ZERO-FILL BUFFER (GIVE EOF NEXT TIME)
.IF EQ	MMG$T
	MOVB	@R5,@-(R4)	;PUT CHARACTER INTO BUFFER
	INC	(R4)+		;BUMP BUFFER POINTER
	DEC	@R4		;DECREASE BYTE COUNT
.IFF
	MOVB	@R5,-(SP)	;GET A CHARACTER
	JSR	PC,@$PTBYT	;MOVE IT TO USER'S BUFFER
	DEC	Q$WCNT(R4)	;DECREASE BYTE COUNT
.ENDC ;EQ MMG$T
	BEQ	PCDONE		;IF ZERO, WE ARE DONE WITH THIS READ REQUEST
PCGORD:	BIS	#PINT,-(R5)	;ENABLE READER INTERRUPT, GET A CHARACTER
	RTS	PC

PREOF:	CLR	-(R5)		;DISABLE READER INTERRUPTS
	.FORK	PCFBLK		;REQUEST SYSTEM PROCESS
1$:				;CLEAR REMAINDER OF USER BUFFER
.IF EQ	MMG$T
	CLRB	@-(R4)		;CLEAR A BYTE
	INC	(R4)+		;BUMP BUFFER ADDRESS
	DEC	@R4		;COUNT DOWN BYTES REMAINING
.IFF
	CLR	-(SP)		;SET NULL BYTE
	JSR	PC,@$PTBYT	;PUT BYTE INTO USER BUFFER
	DEC	Q$WCNT(R4)	;COUNT DOWN BYTES REMAINING
.ENDC ;EQ MMG$T
	BNE	1$		;LOOP UNTIL DONE
PCDONE:	CLR	@#PC$CSR	;TURN OFF THE READER INTERRUPT
.IF EQ	PR11$X
	CLR	@#PP$CSR	;TURN OFF THE PUNCH INTERRUPT
.ENDC ;EQ PR11$X
	CLR	PCFBLK+2	;CLEAR FORK BLOCK TO AVOID DISPATCH
PCFIN:	.DRFIN	PC		;GO TO I/O COMPLETION

PCFBLK:	.WORD	0,0,0,0		;FORK QUEUE BLOCK

	.DREND	PC

.END