head	1.2;
access;
symbols;
locks; strict;
comment	@# @;


1.2
date	2008.03.14.15.26.37;	author dilbert57;	state dead;
branches;
next	1.1;
commitid	509c47da99224567;

1.1
date	2007.12.09.16.06.10;	author dilbert57;	state Exp;
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next	;
commitid	15a2475c11894567;


desc
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1.2
log
@Removing old source code
@
text
@***************************************************
*
* ACIA_IO
* Interrupt driven ACIA driver
*
***************************************************
*
IO	EQU	$E000
RAM	EQU	$DFC0
ROM 	EQU	$F800
*
*
MONITOR	EQU	ROM+0
IRQVEC	EQU	RAM+8
ACIACS	EQU	IO+8
ACIADA	EQU	IO+9
RXFULL	EQU	$01
TXEMPTY	EQU	$02
RXIENB	EQU	$80
TXIENB	EQU	$20
ACIRQ	EQU	$80
*
IFLAG	EQU	$10
*
*
*
	ORG	$0100
START	LBRA	LOOP
ACMASK	FCB	$11
IRQSAV  FDB     0
*
* Receive Buffer
*
RXBLEN	EQU	8192
RXIPTR	FDB	RXBUFF
RXOPTR	FDB	RXBUFF
RXCNT	FDB	0
RXBUFF	RMB	RXBLEN
*
* Transmit Buffer
*
TXBLEN	EQU	16
TXIPTR	FDB	TXBUFF
TXOPTR	FDB	TXBUFF
TXCNT	FDB	0
TXBUFF	RMB	TXBLEN
*
* Initialize ACIA Driver
*
ACINIT	EQU	*
	PSHS	A,X
	ORCC	#IFLAG
        LDX     IRQVEC
        STX     IRQSAV
	LDX	#ACIJMP
	STX	IRQVEC
*
	LDX	#RXBUFF
	STX	RXIPTR
	STX	RXOPTR
        LDX     #$0000
	STX	RXCNT
*
	LDX	#TXBUFF
	STX	TXIPTR
	STX	TXOPTR
        LDX     #$0000
	STX	TXCNT
*
	LDA	#$03	; reset ACIA
	STA	ACIACS
	LDA	ACMASK
	STA	ACIACS
	LDA	ACIADA
*
	LDA	ACMASK	; Enable RX Interrupts
	ORA	#RXIENB
	STA	ACMASK
	STA	ACIACS
*
	ANDCC	#$FF-IFLAG
	PULS	A,X,PC
*
*
* ACIA INTERRUPT
*
*
* Get Character from RX buffer
* Entry: None
* Exit:  Z=1 if buffer empty 
* 	 ACCA = Character
*
RXGETC	PSHS	B,X	; Save registers
	ORCC	#IFLAG	; Mask ACIA IRQs
*
	LDX	RXCNT	; Anything in buffer ?
	BEQ	RXGETC2	; No, exit with Z flag set
	LEAX    -1,X	; One less character in buffer
	STX	RXCNT
*
	LDX	RXOPTR	; Point to next byte in buffer
	LDA	,X+	; fetch it
	CMPX	#RXBUFF+RXBLEN	; Reached end of buffer ?
	BNE	RXGETC1	; No, store pointer
	LDX	#RXBUFF	; Yes, wrap to start of buffer
RXGETC1	STX	RXOPTR	; Update pointer
*
RXGETC2	ANDCC	#$FF-IFLAG ; Enable interrupts
	PULS	B,X,PC	; restore registers and return
*
* Put Character in TX buffer
* Entry: ACCA = Character
* Exit:  Z=1 if buffer full
*
TXPUTC	PSHS	B,X	; Save registers
	ORCC	#IFLAG	; Mask ACIA IRQs
*
	LDB	ACMASK	; Test if TX interrupt enabled
	BITB	#TXIENB
	BNE	TXPUTC1	; Yes, put character in output buffer
	ORB	#TXIENB	; no, Enable TX interrupt
	STB	ACMASK
	STB	ACIACS
	STA	ACIADA	; output character directly to ACIA
	BRA	TXPUTC3	; exit
*
TXPUTC1	LDX	TXCNT	; Test if buffer full
	CMPX	#TXBLEN
	BEQ	TXPUTC3	; Buffer full, exit with Carry set
	LEAX    1,X	; Buffer not full, bump byte count
	STX	TXCNT
*
	LDX	TXIPTR	; Pointer to buffer input
	STA	,X+	; Store charcater in buffer
	CMPX	#TXBUFF+TXBLEN ; Need to wrap buffer pointer ?
	BNE	TXPUTC2	; no, update pointer
	LDX	#TXBUFF	; yes, point to start of buffer
TXPUTC2	STX	TXIPTR
TXPUTC3	ANDCC	#$FF-IFLAG ; Clear interrupt mask
	PULS	B,X,PC	; restore registers and exit
*
* ACIA Interrupt service routine
*
ACIJMP	EQU	*
	LDA	ACIACS	; Fetch ACIA status
	BITA	#$ACIRQ ; Interrupt from ACIA ?
	BEQ	ACIJMPX ; no, exit
*
	BITA	#RXFULL ; receive interrupts ?
	BNE	ACIJRX	; yes, go service
ACIJMP1	BITA	#TXEMPTY ; transmit interrupt ?
	BNE	ACIJTX	; yes, go service
*
ACIJMPX	RTI		; return from interrupt
*
* Character Receiver, put in RX input buffer
*
ACIJRX	LDA	ACIADA	; Get character from ACIA
*
	LDX	RXCNT
	CMPX	#RXBLEN	; Is input buffer full ?
	BEQ	ACIJRX2	; yes, test for TX interrupt before exiting
	LEAX    1,X
	STX	RXCNT	; Update Buffer byte count
*
	LDX	RXIPTR	; Point to RX input pionter
	STA	,X+	; Store character in buffer
	CMPX	#RXBUFF+RXBLEN ; Reached end of buffer
	BNE	ACIJRX1 ; no, update pointer
	LDX	#RXBUFF ; yes, wrap around to start of buffer
ACIJRX1	STX	RXIPTR
*
ACIJRX2 LDA	ACIACS	; Fetch ACIA status
	BRA	ACIJMP1	; test for TX interrupt before exiting
*
* Character Transmitter, get next from buffer
*
ACIJTX	LDX	TXCNT	; Any more characters to output ?
	BNE	ACIJTX1	; yes, fetch from tx buffer
*
	LDB	ACMASK	; No, mask TX interrupt
	ANDB	#$FF-TXIENB
	STB	ACMASK
	STB	ACIACS
	BRA	ACIJMPX	; Exit interrupt routine
*
ACIJTX1 LEAX    -1,X 
	STX	TXCNT	; One less character in buffer
*
	LDX	TXOPTR	; Point to next output character
	LDA	,X+	; fetch byte
	CMPX	#TXBUFF+TXBLEN	; Reached end of buffer ?
	BNE	ACIJTX2	; no, update pointer
	LDX	#TXBUFF	; yes, wrap to start of buffer
ACIJTX2	STX	TXOPTR	; Store pointer
*
	STA	ACIADA	; Ouput Character to ACIA
	BRA	ACIJMPX	; return from interrupt
*
* Main line loop
*
LOOP	LBSR	ACINIT	; Initialise ACIA and Buffers
LOOP1	LBSR	RXGETC	; Get character
	BEQ	LOOP1
	CMPA	#$1A    ; Ctrl Z exits
	BEQ	EXIT
	LBSR	TXPUTC	; Echo character
        BRA     LOOP1
*
* Disable ACIA interrupts
*
EXIT    ORCC    #IFLAG
	LDA	ACMASK	; Enable RX Interrupts
	ANDA	#$FF-RXIENB-TXIENB
	STA	ACMASK
	STA	ACIACS
*
* Restore IRQ vector
*
        LDX     IRQSAV
        STX     IRQVEC
        ANDCC   #$FF-IFLAG
	JMP	[MONITOR]
*
        END

@


1.1
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@New directory structure
@
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