MIKBUG for SBC6800

MIKBUG.ASM

	NAM    MIKBUG
*	REV 009
*	COPYRIGHT 1974 BY MOTOROLA INC
*
*	MIKBUG (TM)
*
*	L  LOAD
*	G  GO TO TARGET PROGRAM
*	M  MEMORY CHANGE
*	P  PRINT/PUNCH DUMP
*	R  DISPLAY CONTENTS OF TARGET STACK
*		CC   B   A   X   P   S
*
*	ADDRESS
ACIACS	EQU	$8018
ACIADA	EQU	$8019
VAR	EQU	$1F00
*
*	OPT	MEMORY
	ORG	$E000
*
*	I/O INTERRUPT SEQUENCE
IO	LDX	IOV
	JMP	X
*
*	NMI SEQUENCE
POWDWN	LDX	NIO	GET NMI VECTOR
	JMP	X
*
*	L COMMAND
LOAD    EQU	*
	LDAA	#$0D
	BSR	OUTCH
	NOP
	LDAA	#$0A
	BSR	OUTCH
*
*	CHECK TYPE
LOAD3	BSR	INCH
	CMPA	#'S
	BNE	LOAD3	1ST CHAR NOT (S)
	BSR	INCH	READ CHAR
	CMPA	#'9
	BEQ	LOAD21	START ADDRESS
	CMPA	#'1
	BNE	LOAD3	2ND CHAR NOT (1)
	CLR	CKSM	ZERO CHECKSUM
	BSR	BYTE	READ BYTE
	SUBA	#2
	STAA	BYTECT	BYTE COUNT
*
*	BUILD ADDRESS
	BSR	BADDR
*
*	STORE DATA
LOAD11	BSR	BYTE
	DEC	BYTECT
	BEQ	LOAD15	ZERO BYTE COUNT
	STAA	X	STORE DATA
	INX
	BRA	LOAD11
*
*	ZERO BYTE COUNT
LOAD15	INC	CKSM
	BEQ	LOAD3
LOAD19	LDAA	#'?	PRINT QUESTION MARK
	BSR	OUTCH
LOAD21	EQU	*
C1	JMP	CONTRL
*
*	BUILD ADDRESS
BADDR	BSR	BYTE	READ 2 FRAMES
	STAA	XHI
	BSR	BYTE
	STAA	XLOW
	LDX	XHI	(X) ADDRESS WE BUILT
	RTS
*
*	INPUT BYTE (TWO FRAMES)
BYTE	BSR	INHEX	GET HEX CHAR
	ASLA
	ASLA
	ASLA
	ASLA
	TAB
	BSR	INHEX
	ABA
	TAB
	ADDB	CKSM
	STAB	CKSM
	RTS
*
*	OUT HEX BCD DIGIT
OUTHL	LSRA	OUT HEX LEFT BCD DIGIT
	LSRA
	LSRA
	LSRA
OUTHR	ANDA	#$F	OUT HEX RIGHT BCD DIGIT
	ADDA	#$30
	CMPA	#$39
	BLS	OUTCH
	ADDA	#$7
*
*	OUTPUT ONE CHAR
OUTCH	JMP	OUTEEE
INCH	JMP	INEEE
*
*	PRINT DATA POINTED AT BY X-REG
PDATA2	BSR	OUTCH
	INX
PDATA1	LDAA	X
	CMPA	#4
	BNE	PDATA2
	RTS		STOP ON EOT
*
*	CHANGE MENORY (M AAAA DD NN)
CHANGE	BSR	BADDR	BUILD ADDRESS
CHA51	LDX	#MCL
	BSR	PDATA1	C/R L/F
	LDX	#XHI
	BSR	OUT4HS	PRINT ADDRESS
	LDX	XHI
	BSR	OUT2HS	PRINT DATA (OLD)
	STX	XHI	SAVE DATA ADDRESS
	BSR	INCH	INPUT ONE CHAR
	CMPA	#$20
	BNE	CHA51	NOT SPACE
	BSR	BYTE	INPUT NEW DATA
	DEX
	STAA	X	CHANGE MEMORY
	CMPA	X
	BEQ	CHA51	DID CHANGE
	BRA	LOAD19	NOT CHANGED
*
*	INPUT HEX CHAR
INHEX	BSR	INCH
	SUBA	#$30
	BMI	C1	NOT HEX
	CMPA	#$09
	BLE	IN1HG
	CMPA	#$11
	BMI	C1	NOT HEX
	CMPA	#$16
	BGT	C1	NOT HEX
	SUBA	#7
IN1HG	RTS
*
*	OUTPUT 2 HEX CHAR
OUT2H	LDAA	0,X	OUTPUT 2 HEX CHAR
OUT2HA	BSR	OUTHL	OUT LEFT HEX CHAR
	LDAA	0,X
	INX
	BRA	OUTHR	OUTPUT RIGHT HEX CHAR AND R
*
*	OUTPUT 2-4 HEX CHAR + SPACE
OUT4HS	BSR	OUT2H	OUTPUT 4 HEX CHAR + SPACE
OUT2HS	BSR	OUT2H	OUTPUT 2 HEX CHAR + SPACE
*
*	OUTPUT SPACE
OUTS	LDAA	#$20	SPACE
	BRA	OUTCH	(BSR & RTS)
*
*	ENTER POWER  ON SEQUENCE
START	EQU	*
	LDS	#STACK
	STS	SP	INZ TARGET'S STACK PNTR
*
*	ACIA INITIALIZE
	LDAA	#$03	RESET CODE
	STAA	ACIACS
	NOP
	NOP
	NOP
	LDAA	#$15	8N1 NON-INTERRUPT
        STAA	ACIACS
*
*	COMMAND CONTROL
CONTRL	LDS	#STACK	SET CONTRL STACK POINTER
	LDX	#MCL
	BSR	PDATA1	PRINT DATA STRING
	BSR	INCH	READ CHARACTER
	TAB
	BSR	OUTS	PRINT SPACE
	CMPB	#'L
	BNE	*+5
	JMP	LOAD
	CMPB	#'M
	BEQ	CHANGE
	CMPB	#'R
	BEQ	PRINT	STACK
	CMPB	#'P
	BEQ	PUNCH	PRINT/PUNCH
	CMPB	#'G
	BNE	CONTRL
	LDS	SP	RESTORE PGM'S STACK PTR
	RTI	GO
	FCB	1,1,1,1,1,1,1,1	GRUE
*
*	ENTER FROM SOFTWARE INTERRUPT
SFE	EQU	*
	STS	SP	SAVE TARGET'S STACK POINTER
*
*	DECREMENT P-COUNTER
	TSX
	TST	6,X
	BNE	*+4
	DEC	5,X
	DEC	6,X
*
*	PRINT CONTENTS OF STACK
PRINT	LDX	SP
	INX
	BSR	OUT2HS	CONDITION CODES
	BSR	OUT2HS	ACC-B
	BSR	OUT2HS	ACC-A
	BSR	OUT4HS	X-REG
	BSR	OUT4HS	P-COUNTER
	LDX	#SP
	BSR	OUT4HS	STACK POINTER
C2	BRA	CONTRL
*
*	PUNCH DUMP
*	PUNCH FROM BEGINING ADDRESS (BEGA) THRU ENDI
*	ADDRESS (ENDA)
MTAPE1	FCB	$D,$A,'S','1',4	PUNCH FORMAT
	FCB	1,1,1,1	GRUE
PUNCH	EQU	*
	LDX	BEGA
	STX	TW	TEMP BEGINING ADDRESS
PUN11	LDAA	ENDA+1
	SUBA	TW+1
	LDAB	ENDA
	SBCB	TW
	BNE	PUN22
	CMPA	#16
	BCS	PUN23
PUN22	LDAA	#15
PUN23	ADDA	#4
	STAA	MCONT	FRAME COUNT THIS RECORD
	SUBA	#3
	STAA	TEMP	BYTE COUNT THIS RECORD
*
*	PUNCH C/R,L/F,NULL,S,1
	LDX	#MTAPE1
	JSR	PDATA1
	CLRB		ZERO CHECKSUM
*
*	PUNCH FRAME COUNT
	LDX	#MCONT
	BSR	PUNT2	PUNCH 2 HEX CHAR
*
*	PUNCH ADDRESS
	LDX	#TW
	BSR	PUNT2
	BSR	PUNT2
*
*	PUNCH DATA
	LDX	TW
PUN32	BSR	PUNT2	PUNCH ONE BYTE (2 FRAMES)
	DEC	TEMP	DEC BYTE COUNT
	BNE	PUN32
	STX	TW
	COMB
	PSHB
	TSX
	BSR	PUNT2	PUNCH CHECKSUM
	PULB		RESTORE STACK
	LDX	TW
	DEX
	CPX	ENDA
	BNE	PUN11
	BRA	C2	JMP TO CONTRL
*
*	PUNCH 2 HEX CHAR UPDATE CHECKSUM
PUNT2	ADDB	0,X	UPDATE CHECKSUM
	JMP	OUT2H	OUTPUT TWO HEX CHAR AND RTS
*
	FCB	1,1,1,1,1,1	GRUE
MCL	FCB	$D,$A,'*',4
	FCB	1,1,1,1	GRUE
*
*	SAVE X REGISTER
SAV	STX	XTEMP
	RTS
	FCB	1,1,1	GRUE
*
*	INPUT ONE CHAR INTO A-REGISTER
INEEE
	BSR	SAV
IN1	LDAA	ACIACS
	ASRA
	BCC	IN1	RECEIVE NOT READY
	LDAA	ACIADA	INPUT CHARACTER
	ANDA	#$7F	RESET PARITY BIT
	CMPA	#$7F
	BEQ	IN1	IF RUBOUT, GET NEXT CHAR
	BSR	OUTEEE
	RTS
	FCB	1,1,1,1,1,1,1,1	GRUE
	FCB	1,1,1,1,1,1,1,1	GRUE
	FCB	1	GRUE
*
*	OUTPUT ONE CHAR 
OUTEEE	PSH	A
OUTEEE1	LDA A	ACIACS
	ASR A
	ASR A
	BCC	OUTEEE1
	PUL A
	STA A	ACIADA
	RTS
*
*	VECTOR
	ORG	$FFF8
	FDB	IO
	FDB	SFE
	FDB	POWDWN
	FDB	START

        ORG    VAR
IOV     RMB    2         IO INTERRUPT POINTER
BEGA    RMB    2         BEGINING ADDR PRINT/PUNCH
ENDA    RMB    2         ENDING ADDR PRINT/PUNCH
NIO     RMB    2         NMI INTERRUPT POINTER
SP      RMB    1         S-HIGH
        RMB    1         S-LOW
CKSM    RMB    1         CHECKSUM

BYTECT  RMB    1         BYTE COUNT
XHI     RMB    1         XREG HIGH
XLOW    RMB    1         XREG LOW
TEMP    RMB    1         CHAR COUNT (INADD)
TW      RMB    2         TEMP
MCONT   RMB    1         TEMP
XTEMP   RMB    2         X-REG TEMP STORAGE
        RMB    46
STACK   RMB    1         STACK POINTER

        END