Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
MIKBUG for SBC6800
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
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.