Libris Britannia 4/science library(b).zip/science library(b)/PROGRAMM/ASSEMBLE/H145.ZIP/ASXXXX_3.ZIP/MOND09.ASM

Assembly Source File | 1990-07-18 | 55KB | 2,290 lines

    .title    MONDEB - 09

    ;    *********************************************************
    ;    *                            *
    ;    *    MONDEB - 09  -  a monitor/debugger        *
    ;    *        for the 6809  microprocessor        *
    ;    *                            *
    ;    *********************************************************
    ;
    ; author:    Don Peters    (6800 version)
    ; date:        April 1977
    ;
    ; modified for the 6809
    ; by:        Alan R. Baldwin
    ; date:        Nov 1988
    ;
    ;      This 6809 monitor/debugger does not use the
    ;    direct page addressing mode.  Thus the user
    ;    program has complete control of the page
    ;    assignment and may use the monitor routines
    ;    without concern for variable locations.
    ;
    ;      To add user functions to MONDEB - 09
    ;
    ;    1) add your commands to the end of command list #1
    ;    2) add the command entry points to the jump table
    ;    3) append any local command lists after MONDEB's
    ;    4) provide an external initialization routine to
    ;        set up the console (and/or alternate)
    ;        ports and any other start up processing.
    ;       MONDEB will call 'userinit' if inituser = 1.
    ;

    .module    mond09

    standalone = 0    ; standalone flag indicating the
            ; vectors and associated code are
            ; to be included during assembly

    inituser = 0    ; call 'userinit' flag indicating
            ; a user startup routine will be
            ; called during intialization

    .page
    .sbttl    MONDEB - 09 working variables

    .radix    d

    .if    standalone

    .area    WORKPG    (REL,CON)

    .else

    .area    WORKPG    (ABS,OVR)

    .endif

    .setdp    0

workpg:    .blkb    256-(endpg-mstack)
            ; main stack storage
mstack:    .blkb    12    ; stack storage for rti instruction

ttybuf:    .blkb    72    ; start of input line buffer
ttyend:    .blkb    1    ; end of input line buffer
bufbeg:    .blkb    2    ; input line start of buffer
bufend:    .blkb    2    ; input line end of buffer

comadr:    .blkb    2    ; address of beginning of command lists
synptr:    .blkb    2    ; input line character pointer for good syntax
linptr:    .blkb    2    ; input line character pointer (content =>
            ; content of synptr)
bolflg:    .blkb    1    ; "beginning of line flg"
delim:    .blkb    1    ; characters permitted as valid command/modifier
            ; delimiter
ibcode:    .blkb    1    ; input base (1=hex, 2=dec, 3=oct)
dbcode:    .blkb    1    ; display base (1=hex, 2=dec, 3=oct, 4=bin)
dbnbr:    .blkb    1    ; display base number (e.g., 16,10,8, or 2)
nbrhi:    .blkb    1    ; most significant byte of scanned number
nbrlo:    .blkb    1    ; least significant byte of scanned number
ranglo:    .blkb    2    ; range lower limit picked up by gtrang
ranghi:    .blkb    2    ; range upper limit picked up by gtrang
verfrm:    .blkb    2    ; beginning address of range to verify
verto:    .blkb    2    ; ending address of range to checksum verify
chksum:    .blkb    1    ; checksum of range given in the verify command
brkadr: .blkb    2    ; address of inserted breakpoint
brkins:    .blkb    1    ; instruction which should be there normally
inpflg:    .blkb    1    ; alternate input flag
outflg:    .blkb    1    ; alternate output flag
outadr:    .blkb    2    ; alternate address that the output chars go to
hdxflg:    .blkb    1    ; half-duplex terminal flag (if non-zero, no echo)
cplcnt:    .blkb    1    ; "characters per line" count
cplmax:    .blkb    1    ; "characters per line" maximum

    ; temporary (locally used) variables

temp1:    .blkb    2    ; in: main
temp2:    .blkb    2    ; in: main
temp3:    .blkb    2    ; in: main
temp4:    .blkb    2    ; in: main
temp5:    .blkb    2    ; in: main
temp6:    .blkb    2    ; in: main

nummat:    .blkb    1    ; used in command
lisnum:    .blkb    1    ; used in command
comnum:    .blkb    1    ; used in command
lisptr:    .blkb    2    ; used in command
decdig:    .blkb    1    ; decimal digit being built
numbhi:    .blkb    1    ; used by outnum
numblo:    .blkb    1    ; used by outnum
nbr2x:    .blkb    2    ; used by number
timcon:    .blkb    2    ; delay time constant
bytect:    .blkb    1    ; record byte count used in load command
cksm:    .blkb    1    ; record checksum used in load command

conin:    .blkb    2    ; address of console input routine
conout:    .blkb    2    ; address of console output routine
altin:    .blkb    2    ; address of alternate input routine
altout:    .blkb    2    ; address of alternate output routine

.rsrvd:    .blkb    2    ; reserved vector
.swi3:    .blkb    2    ; swi3 vector
.swi2:    .blkb    2    ; swi2 vector
.firq:    .blkb    2    ; firq vector
.irq:    .blkb    2    ; irq vector
.swi:    .blkb    2    ; swi vector
.nmi:    .blkb    2    ; nmi vector
spsave:    .blkb    2    ; saved stack pointer
endpg:

    ; convenient equivalences for local variables

memadr    =    temp1    ; display, set, search, test
strnum    =    temp2    ; fndstr
eoschr    =    temp2+1    ; fndstr

    ; for "search" command

bytptr    =    temp2
nbytes    =    temp3
nbrmat    =    temp3+1
bytstr    =    temp4

    ; other constants

cr    =    13    ; carriage return
lf    =    10    ; line feed


    .page
    .sbttl    MOND09 Startup

    .if    standalone

    .area    MONDEB    (REL,CON)

reset:    lds    #mstack+12    ; load stack pointer
    bsr    mond09        ; stack pc and start mondeb
    bra    reset
    .else

    .area    MONDEB    (ABS,OVR)

    .endif

mond09:    pshs    u,y,x,dp,b,a,cc    ; pseudo swi
    sts    spsave        ; save the pointer
    orcc    #0b01010000    ; hold irq and firq interrupts
    lds    #mstack        ; initialize the stack pointer
    jsr    inital        ; initialize variables
    jsr    docrlf        ; advance to a clean line
    ldx    #msghed        ; get address of header
    jsr    outstr        ; type it
    ldx    #ttybuf-1    ; get address of terminal input buffer
    stx    bufbeg        ; save it
    ldx    #ttyend        ; define end of input buffer
    stx    bufend        ; 72 char capacity, incl cr
    lda    #3        ; delimiter class definition
    sta     delim        ; space or comma (code 3)
    bra    promp1

    ; prepare to get a new command

prompt:    jsr    docrlf    ; type cr-lf
    inc    bolflg    ; set 'beginning of line' flag
    ldx     synptr    ; point to current character
    lda    ,x    ; get it
    cmpa    #';    ; semicolon?
    beq    getcmd    ; continue scan if it is,
            ; skipping the prompt
promp1:    ldx    #msgprm    ; type prompt
    jsr    outstr
    jsr    getlin    ; get line of input
    cmpb    #3    ; abort line on a control-c
    beq    prompt

    ldx    bufbeg    ; set syntax scanning pointer
    stx    synptr    ; to beginning of buffer/line
    lda    1,x    ; get first char
    jsr    tsteol    ; reprompt on an empty line
    beq    prompt    ; (first char = cr,lf,or ;)

    .page
    .sbttl    Get Command

getcmd:    lda    #1    ; use list 1 when matching
    jsr    comand    ; now go for a match
    beq    prompt    ; reprompt if just a cr was typed
    bgt    jmpcmd    ; good command if positive

badsyn: ldx    bufbeg    ; get start of line

1$:    cpx    linptr    ; space over to the error in syntax
    beq    2$    ; at error ?
    jsr     outsp    ; output a space
    inx        ; no, move on
    bra    1$

    ; the 'extra' char '1' is compensated for by the prompt
    ; char on the preceeding line

2$:    lda    #'^    ; at error - get an up-arrow
    jsr    outchr    ; print it
    jsr    docrlf
    bra    promp1    ; ignore any succeeding packed
            ; commands

    ; *******
    ; *there should be no more characters on the input line
    ;    (except delimiters)

nomore:    jsr    skpdlm
    bcs    prompt    ; if carry bit set, end of line
            ; (normal)
    bra    badsyn    ; there is something there but shouldn't be

    .page
    .sbttl    Command Dispatcher

    ; ******
    ; execute a computed 'goto' to the proper command

jmpcmd:    asla        ; multiply command by 2
    ldx    #1$-2
    jmp    [a,x]    ; jump to designated command

1$:    .word    break
    .word    contin
    .word    compar
    .word    copy
    .word    displa
    .word    dbase
    .word    delay
    .word    dump
    .word    goto
    .word    help
    .word    ibase
    .word    load
    .word    reg
    .word    set
    .word    search
    .word    test
    .word    verify
    .word    cli
    .word    clf
    .word    sei
    .word    sef
    .word    xirq
    .word    xfirq
    .word    xnmi
    .word    xrsrvd
    .word    xswi
    .word    xswi2
    .word    xswi3

    .page
    .sbttl    REG - display registers

reg:            ; print stack stored swi data
disreg:    ldx    spsave    ; get saved stack pointer
    clr    comnum    ; start at beginning of the
            ; register name list
    bsr    1$    ; type condition codes
    bsr    1$    ; type acca
    bsr    1$    ; type accb
    bsr    1$    ; type dp
    jsr    docrlf    ; advance to a clean line
    bsr    2$    ; type index reg x
    bsr    2$    ; type index reg y
    bsr    2$    ; type index reg u
    jsr    docrlf    ; advance to a clean line
    leax    -9,x    ; back to d
    bsr    2$    ; type d
    leax    7,x    ; back to pc
    bsr    2$    ; type program counter

    ; type the stack pointer location

    bsr    3$    ; type stack pointer id
    ldx    #spsave
    jsr    out2by    ; type the value
    jmp    nomore

    ; output content of a 1 byte register

1$:    bsr    3$
    jsr    out1by
    inx
    rts

    ; output content of a 2 byte register

2$:    bsr    3$
    jsr    out2by
    leax    2,x    ; skip to next word in stack
    rts

    ; misc setup for register display

3$:    jsr    outsp    ; output a space
    inc    comnum    ; skip to next register name
    lda    #5    ; register name is in list 5
    jsr    typcmd    ; type it
    jsr    outeq    ; type an '='
    rts

    .page
    .sbttl    Software Interrupt Entry Point

typswi:    sts    spsave
    ldx    #msgswi
    jsr    outstr

    ; decrement pc so it points to 'swi' instruction

    ldx    spsave
    ldd    10,x
    subd    #1
    cmpd    brkadr    ; a break point ?
    bne    disreg    ; no - allow to pass
    std    10,x    ; backup PC
    bra    disreg    ; go display registers

    .sbttl    GOTO - Go To Memory Address

goto:    jsr    mnumber    ; get destination
    beq    contin    ; if none, just continue
    ldd    nbrhi
    lds    spsave    ; place new PC
    std    10,s    ; fall through to Continue

    .sbttl    Continue - Continue From a 'SWI'

contin:    lds    spsave    ; in case sp was modified via set
    rti        ; command

    .sbttl    SEI - Set Interrupt Mask

sei:    orcc    #0b00010000
    jmp    nomore

    .sbttl    CLI - Clear Interrupt Mask

cli:    andcc    #~0b00010000
    jmp    nomore

    .sbttl    SEF - Set Fast Interrupt Mask

sef:    orcc    #0b01000000
    jmp    nomore

    .sbttl    CLF - Clear Fast Interrupt Mask

clf:    andcc    #~0b01000000
    jmp    nomore

    .page
    .sbttl    COPY - Copy From One Location To Another

copy:    jsr    gtrang    ; get source range into ranglo &
            ; ranghi
    lble    badsyn    ; error if no source
    jsr    mnumber    ; get destination
    lble    badsyn    ; error if no destination
    ldx    ranglo    ; get source address pointer
    ldu    nbrhi    ; get destination address pointer
    lda    ,x    ; get byte from source
1$:    sta    ,u+    ; save byte in destination
    cpx    ranghi    ; compare to end of input range
    lbeq    nomore    ; done if equal
    lda    ,x+    ; get byte from source
    bra    1$    ; loop for next byte

    .page
    .sbttl    BREAK - Set Breakpoint at Specified Address

break:    jsr    mnumber    ; get breakpoint location
    bmi    3$    ; if not numeric, look for '?'
    beq    2$    ; if no modifier, remove old breakpoint
    ldx    brkadr    ; get current break address
    lda    ,x    ; and the char there
    cmpa    #0x3f    ; compare to 'swi'
    bne    1$    ; equal?
    lda    brkins    ; yes, restore the old instruction
    sta    ,x    ; restore it

1$:    ldx    nbrhi    ; get new breakpoint
    stx    brkadr    ; save it
    lda    ,x    ; get instruction stored there
    sta    brkins    ; save it
    lda    #0x3f    ; get code for software interrupt
    sta    ,x    ; put it at breakpoint
    bra    5$    ; all done

2$:    ldx    brkadr    ; get address of break
    lda    ,x    ; get inst. there
    cmpa    #0x3f    ; swi?
    bne    5$    ; if not, return & prompt
    lda    brkins    ; was a swi - get previous inst.
    sta    ,x    ; & restore it
    bra    5$

3$:    lda     #4
    jsr    comand    ; scan for it
    lble    badsyn    ; bad syntax if not '?'
    ldx    brkadr    ; it is, get break address
    lda    ,x    ; get instruction there
    cmpa    #0x3f    ; is it a 'swi'?
    beq    4$    ; if yes, say so
    ldx    #msgnbr    ; get that message
    jsr    outstr    ; say it
    bra    5$

4$:    ldx    #msgbat    ; get that message
    jsr    outstr    ; say it
    ldx    #brkadr    ; get break address
    jsr    out2by    ; type it
5$:    jmp    nomore

    .page
    .sbttl    IBASE - Set Input Base

ibase:    lda    #3    ; look for hex,dec,or oct in list #3
    jsr    comand
    bmi    2$    ; unrecognizable base, try'?'
    bgt    1$
    lda    #1    ; no base given - default to hex
1$:    sta    ibcode    ; save base code
    jmp    nomore

2$:    lda    ibcode    ; get ib code in case its needed
    pshs    a    ; save it on stack temporarily
    bra    ibdbq

    .sbttl    DBASE - Set Display Base

dbase:    lda    #3    ; look for hex,dec,oct, or bin in list #3
    jsr    comand
    bmi    3$    ; unrecognizable base, try '?'
    bgt    1$
    lda    #1    ; no base given - default to hex
1$:    sta    dbcode
    ldx    #2$-1    ; get numeric base from table
    lda    a,x
    sta    dbnbr    ; save it
    jmp    nomore    ; done

2$:    .byte    16    ; display base table
    .byte    10
    .byte    8
    .byte    2

3$:    lda    dbcode    ; get db code in case its needed
    pshs a        ; save it on stack temporarily

ibdbq:    lda    #4    ; look for '?' in list #4
    jsr    comand
    puls b        ; retrieve input base/display base code
    lble    badsyn    ; error if the 'something' was not a '?'
    lda    #3    ; base code is in list 3
    stb    comnum    ; store base code
    jsr    typcmd    ; type out base
    jmp    nomore

    .page
    .sbttl    Display - Display Memory Data

displa:    jsr    gtrang    ; get memory display range
    lble    badsyn    ; address is required
    ldx    ranglo    ; initialize address pointer
    stx    memadr

    lda    #6    ; search list 6 for
    jsr    comand    ; display modifiers 'data' or 'used'
    lbmi    badsyn    ; any other modifier is illegal
    deca        ; adj display modifier code so that:
    sta    comnum    ; -1=addr & data, 0=data, 1=used
    clrb        ; init 'data values per line' counter
    incb
1$:    ldx    #memadr
    tst    comnum    ; which display option?
    bmi    6$    ; if 'address & data', go there
    decb        ; count data values per line
    bne    2$    ; if count not up, skip address output
    jsr    docrlf    ; get to line beginning
    jsr    out2by    ; output address
    jsr    outsp    ; and a space
    ldb    dbnbr    ; reset line counter

2$:    ldx    memadr    ; point to data at that address
    tst    comnum    ; want 'data' option?
    bgt    3$    ; if not, go to 'used' code

    jsr    outsp    ; output preceedng space
    bra     7$

3$:    lda    ,x    ; get the data
    bne     4$
    lda    #'.    ; its zero, get a '.'
    bra     5$

4$:    lda    #'+    ; its non-zero, get a '+'
5$:    jsr    outchr    ; output the '.' or '+'
    bra    8$

6$:    jsr    outsp    ; output a preceeding space
    jsr    out2by    ; type address
    jsr    outeq    ; type    '='
    ldx    ,x    ; get content
7$:    jsr    out1by    ; type it
8$:    cpx    ranghi    ; are we done
    lbeq    nomore    ; if yes, back to prompt
    inx        ; no, inc memory address
    stx    memadr    ; save it
    bra    1$

    .page
    .sbttl    SET - Set Memory Locations

set:    jsr    gtrang    ; get memory location/range
    bmi    5$    ; if not an address, look for a
            ; register name
    lbeq    badsyn    ; an address modifier is required

    ; range of address specified?

    ldx    ranglo
    cpx    ranghi
    beq    2$    ; if single address, set up
            ; addresses individually

    ; set a range of addresses to a single value

    jsr    mnumber    ; get that value
    lble    badsyn    ; its    required
    lda    nbrlo    ; put it in acca
1$:    sta    ,x    ; store it in destination
    cpx    ranghi    ; end of range hit?
    lbeq    nomore    ; if yes, all done
    inx        ; no, on to next address in range
    bra    1$    ; loop to see it

    ; set addresses up individually

2$:    stx    memadr    ; save memory loc
3$:    jsr    mnumber    ; get data to put there
    beq    4$    ; end of line?
    lblt    badsyn    ; abort if bad syntax
    lda    nbrlo    ; load data byte
    ldx    memadr    ; load address
    sta    ,x+    ; store data
    bra    2$

4$:    ldx    synptr    ; point to end of line
    lda    ,x    ; get char there
    cmpa    #lf    ; line feed?
    lbne    nomore    ; if not,back to prompt
    ldx    #memadr    ; yes, get next address to be set
    jsr    out2by    ; type it
    jsr    outsp    ; and a space
    jsr    getlin    ; get a new line
    ldx    bufbeg    ; get buffer beginning
    stx    synptr    ; equate it to syntax scan pointer
    bra    3$    ; go pick up data

    ; look for (register name, register value) pairs

5$:    lda    #5
    jsr    comand    ; pick up a register name
    lbmi    badsyn    ; error if unrecognizable
    lbeq    nomore    ; done if end of line
    pshs a        ; save register name(number)
    jsr    mnumber    ; get new register value
    puls a        ; restore register name(number)
    lble    badsyn    ; got good register value?
    deca
    ldu    #6$
    lda    a,u
    leau    a,u
    ldx    spsave    ; yes, point to top of stack
    ldd    nbrhi    ; get register value
    jsr    ,u    ; go to function
    bra    5$    ; and loop

6$:    .byte    7$-6$
    .byte    8$-6$
    .byte    9$-6$
    .byte    10$-6$
    .byte    11$-6$
    .byte    12$-6$
    .byte    13$-6$
    .byte    14$-6$
    .byte    15$-6$
    .byte    16$-6$

7$:    stb    ,x    ; condition codes
    rts

8$:    stb    1,x    ; acca
    rts

9$:    stb    2,x    ; accb
    rts

10$:    stb    3,x    ; dp
    rts

11$:    std    4,x    ; ix
    rts

12$:    std    6,x    ; iy
    rts

13$:    std    8,x    ; iu
    rts

14$:    std    1,x    ; d
    rts

15$:    std    10,x    ; pc
    rts

16$:    std    spsave    ; sp
    rts

    .page
    .sbttl    Checksum Verify a Block of Memory

verify:    jsr    gtrang    ; get a number range
    beq    1$    ; no modifier means check what we have
    lbmi    badsyn    ; anything else is illegal

    ldx    ranglo    ; good range given,
    stx    verfrm    ; transfer it to checksum addresses
    ldx    ranghi
    stx    verto

    bsr    cksum    ; compute checksum
    sta    chksum    ; save it
    ldx    #chksum    ; type the checksum
    jsr    out1by
    bra    3$

1$:    bsr    cksum    ; compute checksum
    cmpa     chksum    ; same as stored checksum?
    bne     2$

    ldx    #msgver    ; they verify - say so
    jsr    outstr
    bra    3$

2$:    ldx    #msgnve    ; they don't - say so
    jsr    outstr
3$:    jmp    nomore

    ; compute the checksum from addresses verfrm to verto
    ; return the checksum in acca

cksum:    clra        ; init checksum to zero
    ldx    verfrm    ; get first address
    dex        ; init to one less
1$:    inx        ; start of checksum loop
    adda    ,x    ; update checksum in acca with
            ; byte pointed to
    cpx    verto    ; hit end of range?
    bne    1$    ; if not, loop back
    coma        ; complement the sum
    rts        ; return with it


    .page
    .sbttl    Search Memory for Byte String

    ; global variables used
    ;  linptr - input line character pointer
    ;  lisptr - command list character pointer
    ;  ranglo - 'search from' address
    ;  ranghi - 'search to' address
    ;
    ; local variables used
    ;  memadr - starting memory address where a match
    ;        occurred
    ;  bytptr - address pointer used to fill bytstr and
    ;        substr buffers
    ;  nbytes - number of bytes in byte string
    ;  nbrmat - number of chars that match so far in the
    ;        matching process
    ;  bytstr - starting address of 6 character byte sring
    ;        buffer
    ;
    ; the search string occupies temp4, temp5, & temp6
    ;        (6 bytes max)

search:    jsr    gtrang    ; get search range
    lble    badsyn    ; abort if no pair
    ldx    #bytstr    ; get start of byte string
            ; to search for
    stx    bytptr    ; set pointer to it
    clr    nbytes    ; zero # of bytes in byte string

1$:    jsr    mnumber    ; get a byte string
    beq    2$    ; begin search if eol
    lblt    badsyn
            ; good byte, add it to string
    inc    nbytes    ; count this  byte
    lda    nbytes    ; don't accept over 6 bytes
    cmpa    #6
    lbgt    badsyn
    lda    nbrlo    ; get (low order) byte
    ldx    bytptr    ; get byte pointer
    sta    ,x+    ; save byte, bump pointer
    stx    bytptr    ; save it
    bra     1$

2$:    tst    nbytes    ; is # of bytes to look for >0
    lbeq    badsyn    ; if not,bad syntax
    ldx    ranglo    ; initialize memory pointer
    dex
    stx    linptr

3$:    ldx  #bytstr-1    ; initialize byte pointer
    stx    lisptr
    clr    nbrmat    ; set 'number of bytes that
            ; matched' to zero
    jsr    getlst    ; get byte from byte string

4$:    jsr    mgetchr    ; get byte from memory range
    cba        ; compare memory & byte string
            ; characters
    beq    5$    ; if no match, test for range end
    cpx    ranghi    ; have we reached the range
            ; search upper limit?
    lbeq    nomore    ; yes, go prompt for next command
    bra    4$

5$:    stx    memadr    ; match achieved - save address of match
6$:    inc    nbrmat    ; bump number matched
    lda    nbrmat
    cmpa    nbytes    ; have all characters matched?
    beq    8$    ; if so, match achieved

    jsr    getlst    ; haven't matched all yet, go get next pair
    jsr    mgetchr    ; even if past 'search to' address
    cba
    beq    6$

7$:    ldx    memadr    ; mismatch on some byte past the first one

    cpx    ranghi    ; this test handles special case
    lbeq    nomore    ; of a match on range end
    stx    linptr
    bra     3$    ; go reset the byte string pointer


8$:    ldx    #memadr    ; match on byte string achieved,
    jsr    out2by    ; type out memory address
    jsr    outsp    ; and a space
    bra     7$

    .page
    .sbttl    Test Ram

test:    jsr    gtrang    ; get an address range
    lble    badsyn    ; abort if no pair
    ldu    ranglo    ; ranglo holds starting address of range
            ; ranghi holds ending address of range
1$:    lda    ,u    ; get byte stored at test location
    pshs    a    ; save it
    clr    ,u    ; zero the location
    tst    ,u    ; test it
    beq    2$    ; ok if = zero
    ldx    #msgccl    ; can't clear location
    bra    4$

2$:    dec    ,u    ; set location to $ff
    lda    #0xff
    cmpa    ,u    ; did it get set to $ff?
    beq    3$
    ldx    #msgcso    ; can't set location to one's
    bra     4$

3$:    puls    a
    sta    ,u    ; restore previous content
    cmpu    ranghi    ; hit end of test range?
    lbeq    nomore    ; yes, all done
    leau    1,u    ; no, move to test next location
    bra    1$

4$:    stx    temp3    ; save error message temporarily
    ldx    #temp4
    stu    ,x
    jsr    out2by    ; type out bad address
    jsr    outeq    ; and equal sign
    ldx    temp4
    jsr    out1by    ; its content
    jsr    outsp    ; a space
    ldx    temp3
    jsr    outstr    ; and the type of error
    jsr    docrlf
    bra    3$

    .page
    .sbttl    vector settup commands

    ; rsrvd - set up rsvd pointer

xrsrvd:    jsr    numinx    ; get pointer in ix
    stx    .rsrvd    ; save it
    jmp    nomore

    ; swi3 - set up swi3 pointer

xswi3:    jsr    numinx    ; get pointer in ix
    stx    .swi3    ; save it
    jmp    nomore

    ; swi2 - set up swi2 pointer

xswi2:    jsr    numinx    ; get pointer in ix
    stx    .swi2    ; save it
    jmp    nomore

    ; firq - set up interrupt pointer

xfirq:    jsr    numinx    ; get pointer in ix
    stx    .firq    ; save it
    jmp    nomore

    ; irq - set up interrupt pointer

xirq:    jsr    numinx    ; get pointer in ix
    stx    .irq    ; save it
    jmp    nomore

    ; swi - set up swi pointer

xswi:    jsr    numinx    ; get pointer in ix
    stx    .swi    ; save it
    jmp    nomore

    ; nmi - set up non-maskable interrupt pointer

xnmi:    jsr     numinx    ; get ponter in ix
    stx    .nmi    ; save it
    jmp    nomore

    .page
    .sbttl    compare numbers

    ; compare - output sum & difference of two input numbers

compar:    jsr    numinx    ; get first number
    stx    ranglo    ; put it in ranglo
    jsr    numinx    ; get second number
    stx    nbrhi    ; save it in nbrhi

    ; compute and output the sum

    jsr    sumnum    ; compute sum
    ldx    #msgsis    ;get its title
    bsr    1$    ; output title & sum

    jsr    difnum    ; compute difference
    ldx    #msgdis    ; get its title
    bsr    1$    ; output title & diff

    jmp    nomore

    ; compute and output the result

1$:    jsr    outstr    ; output it
    ldx    #ranghi    ; get result
    jsr    out2by    ; display result
    rts

    .page
    .sbttl    dump memory in S1-S9 format

    ; *****
    ; dump - dump portion of memory in S1-S9 format
    ;
    ; get address range: start in ranglo (2 bytes), end in
    ;        ranghi (2bytes)
    ; if no address range is given, use whatever is n
    ;        ranlo & ranghi

dump:    jsr    gtrang
    clr    temp5    ; initialize to dump to terminal

1$:    lda    #2    ; look for a 'TO' modifier
    jsr    comand
    beq    2$
    lble    badsyn    ; error if bad syntax
    cmpa    #1    ; TO ?
    bne    1$    ; go look for another modifier

    jsr    numinx    ; get 'TO' address
    stx    outadr    ; save it
    inc    temp5    ; remember this
    bra    1$    ; go look for another modifier

2$:    tst    temp5
    beq    3$
    inc    outflg    ; set flag for proper output device

3$:    ldd    ranghi    ; compute # of bytes to output
    subd    ranglo    ; subtract lo bytes
    cmpd    #16    ; diff 0-15.
    bcs    5$
4$:    ldb    #15

    ; to get frame count, add 1
    ; (diff of 0 implies 1 output) + # of data bytes
    ; + 2 addr bytes + 1 checksum byte

5$:    addb    #4
    stb    temp3    ; temp3 is the frame count
    subb    #3
    stb    temp4    ; temp4 is the record byte count

    ldx    #msgs1    ; output a 'S1' header data record
    jsr    outstr
    clrb        ; zero checksum

    ldx    #temp3    ; punch frame count
    bsr    7$

    ldx    #ranglo    ; punch address
    bsr    7$
    bsr    7$

    ldx    ranglo    ; load memory pointer
6$:    bsr    7$    ; output data byte
    dec    temp4    ; dec byte count
    bne    6$
    stx    ranglo    ; save memory pointer

    comb        ; complement checksum
    pshs    b    ; put it on stack
    tfr    s,x    ; let ix point to it
    bsr    7$    ; output checksum
    puls    b    ; pull it off stack
    ldx    ranglo    ; restore memory pointer
    dex
    cpx    ranghi     ; hit end of range?
    bne    3$

    ldx    #msgs9    ; yes, output an 'S9' record
    jsr    outstr
    clr    outflg    ; set to terminal output
    jmp     nomore

7$:    jsr    out1by    ; output a byte pointed to by ix as
    addb    ,x+    ; 2 hex characters, update checksum
    rts


    .page
    .sbttl    Load S1-S9 format Data

load:    jsr    inpchr    ; get a char
    cmpa    #'S    ; is it an S ?
    bne    load

    jsr    inpchr    ; got an 'S', examine next character
    cmpa    #'9    ; done if its a '9'
    beq    3$

    cmpa    #'1    ; is it a '1'?
    bne    load    ; if not, look for next 'S'

    clr    cksm    ; clear checksum

    jsr    5$    ; read record byte count
    suba    #2
    sta    bytect    ; save count minus 2 address bytes

    bsr    4$    ; build address

1$:    bsr    5$    ; read a data byte into acca
    dec    bytect    ; count it
    beq    2$    ; if done with record, check checksum
    sta    ,x+    ; not done, store byte in memory
    bra    1$    ; on to next memory address

2$:    inc     cksm    ; test checksum by adding 1
    beq    load    ; if ok, result should be zero

    ldx    #msgnve    ; record checksum error
    jsr    outstr
    ldx    #temp1    ; get record address of it
    jsr    out2by    ; type it too
3$:    clr    inpflg    ; reset flag to normal terminal input
    jmp     nomore

4$:    bsr    5$    ; build address
    sta    temp1
    bsr    5$
    sta    temp1+1
    ldx    temp1
    rts

5$:    bsr    6$    ; get left hex digit
    asla        ; move to hi 4 bits
    asla
    asla
    asla
    tab        ; save it in acca
    bsr    6$    ; get right hex digit
    aba        ; combine then in acca
    tab        ; update the checksum
    addb    cksm
    stb    cksm
    rts

6$:    jsr    inpchr    ; input a hex char & convert to internal form
    suba    #'0
    bmi    8$    ; not hex if below ascii '1'
    cmpa    #'9-'0
    ble    7$    ; ok if ascii '9' or less
    cmpa    #'A-'0    ; below ascii 'A'?
    bmi    8$    ; error if it is
    cmpa    #'F-'0    ; over ascii 'F'?
    bgt    8$    ; error if it is
    suba    #7    ; conv ascii A-F to hex A-F
7$:    rts

8$:    ldx    #msgcnh    ; error - char not hex, say so
    jsr    outstr
    rts

    .page
    .sbttl    Delay Function

    ; *****
    ; delay - delay specified # of milliseconds

delay:    jsr    numinx    ; get delay time
    bsr    timdel
    jmp    nomore

    ; *****
    ; time delay subroutine
    ; ix is input as the # of milliseconds to delay
    ; adj timcon so (7*timcon*cycle time=1 ms)

timdel:    pshs    d
1$:    ldd    timcon

2$:    subd    #1    ; a 7 cycle loop
    bne    2$

    dex        ; decrement millisecond counter
    bne    1$
    puls    d,pc

    .page
    .sbttl    Help List

help:    jsr    docrlf    ; next line
    ldx    #comlst    ; command list

1$:    ldb    #4    ; commands per line
    stb    temp1

2$:    ldb    #12    ; positions per command
            ; must be larger than longest command
3$:    lda    ,x+    ; get character
    cmpa    #cr    ; <cr> is end of command
    beq    4$
    jsr    outchr    ; print command character
    decb
    bne    3$

4$:    lda    ,x    ; get character
    cmpa    #lf    ; <lf> is end of list
    beq    6$    ; finished
    dec    temp1    ; per line done ?
    bne    5$    ; no - skip

    jsr    docrlf    ; next line
    bra    1$

5$:    lda    #'     ; space
    jsr    outchr
    decb
    bne    5$
    bra    2$

6$:    jsr    docrlf    ; next line
    jmp    nomore

    .page
    .sbttl    Command Lists

    ;================================================
    ;
    ; c o m m a n d   l i s t   s c a n n i n g
    ;    r o u t i n e
    ;
    ; this routine seeks a match of the characters pointed
    ; at by the input line scanning pointer to one of the
    ; commands in a list specified by acca.
    ; the result of the scan for a match is returned in
    ; acca as follows:
    ;
    ;    acca=-1: the match was unsuccessful. the syntax
    ;         pointer (synptr) was not updated
    ;            (advanced).
    ;
    ;    acca= 0: the match was unsuccessful since there
    ;            were
    ;          no more characters, i.e., the end of
    ;            the
    ;        line was reached.
    ;
    ;    acca=+n: successful match. the syntax pointer
    ;            was updated
    ;         to the first character following the
    ;          command
    ;          delimiter.  acca holds the number of
    ;              the
    ;          command matched.
    ; global variables for external communication
    ; synptr - good syntax input line char pointer
    ; linptr - input line character pointer
    ; delim - class of permissible command delimiters
    ;
    ; temporary 2 byte internal variables
    ; lisptr - command list character pointer
    ;
    ; temporary 1 byte internal variables
    ; nummat - number of characters that successfully match
    ; lisnum - # of list within which a match will be sought
    ; comnum - command number matched
    ;
    ; constants used
    ; cr - carriage return
    ; lf - line feed
    ;
    ; a, b & ix are not preserved

comand:    sta    lisnum    ; save list # to match within
    jsr    skpdlm    ; test if we are at the end of the line
    bcc    1$
    clra
    rts

    ; initialize the command list pointer to one less than
    ;         the beginning of the command lists

1$:    ldx    comadr    ; entry point

    ; move to the beginning of the desired command list

    lda    lisnum    ; search for 'string' # lisnum
    ldb    #lf    ; use lf as a 'string' terminator
    bsr    fndstr
    stx    lisptr

    ; the list pointer, lisptr, now points to one less than
    ; the first character
    ; of the first command in the desired list

    clr    comnum

    ; reset input line pointer to: 1) beginning of line, or
    ; to 2) point where last successful scan terminated

2$:    inc    comnum    ; initialize the command # to 1
    ldx    synptr
    stx    linptr
    clr    nummat    ; clear number of characters
            ; matched
3$:    jsr    mgetchr    ; get input line char in accb
    jsr    tstdlm    ; test for a delimiter
    bne    4$    ; success (found delimiter)
    jsr    getlst    ; get command list char in acca
    cmpa    #lf    ; has end of command list been reached ?
    beq    5$    ; if so, potential match failure
    cmpa    #cr    ; has end of command been reached ?
    beq    5$    ; if so, potential match failure
    cba        ; compare the two characters
    bne    6$    ; match not possible on this command
    inc    nummat    ; they match, compare the succeeding characters
    bra    3$    ; inc number of characters matched

4$:    ldx    linptr    ; successful match
    stx    synptr    ; update good syntax pointer
    lda    comnum    ; return command number
    rts

    ; no match

5$:    tst    nummat    ; did at least one match?
    beq    6$    ; to next command if none matched
    jsr    tstdlm    ; at least one matched - test for delimiter
    bne    4$    ; if a delimiter, match has been achieved
    lda    ,x    ; retrieve last character

    ; illegal delimiter
    ; move to next command within list

6$:    cmpa    #lf    ; end of this list?
    beq    7$    ; if so, nothing on list matched
    cmpa    #cr    ; is it a cr?
    beq    2$    ; yes, next command
    jsr    getlst    ; get next command list character
    bra    6$    ; no, get to end of command

7$:    clra    ; match failure
    deca    ; no match possible within this list
    rts

    .page
    .sbttl    Typeout Command

    ;====================================
    ; this routine types out command number "comnum"
    ; the list is specified in acca
    ; accb & ix are preserved

typcmd:    pshs    b,x
    ldx  #comlst-1    ; move to head of command lists
    ldb    #lf    ; and list terminator
    bsr    fndstr    ; go to head of desired list
    lda    comnum    ; get command number
    ldb    #cr    ; get command terminator
    bsr    fndstr    ; go to head of desired command

1$:    inx        ; move to next character
    lda    ,x    ; get a command character
    cmpa    #cr    ; is it a command terminator?
    beq    2$    ; if so, return
    jsr    outchr    ; no, type it
    bra    1$

2$:    puls    b,x,pc

    .page
    .sbttl    Find string

    ;======================================
    ; move to beginning of desired string number (in acca)
    ; each string is terminated by an end of string
    ;   character (in accb)
    ; the index register is assumed initialized pointing to
    ; one less than the first character of the first string
    ; acca, accb & ix are not preserved
    ; local variables
    ; strnum - string # to find
    ; eoschr - "end of string" character

fndstr:    sta    strnum    ; save string number
    stb    eoschr    ; save terminator
    clrb
1$:    incb        ; string 1 is the first string
    cmpb    strnum    ; is this the right string?
    beq    3$    ; if so, done

    ; no, swallow up characters until an end of string char is hit

2$:    inx        ; bump pointer to next one
    lda    ,x    ; get char pointed at
    cmpa    eoschr    ; end of string hit?
    beq    1$    ; if it is, bump the string counter
    bra    2$    ; no, move on to next char
3$:    rts        ; ix set properly, return

    .page
    .sbttl    Skip Leading Delimiters

    ;=================================================
    ; skip leading delimiters
    ; this routine should be called prior to scanning for
    ; any information
    ; on the input line
    ; the current character is ignored if the scannng
    ; pointer is at the beginning of a line. if not, the
    ; scanning pointer skips over spaces and commas
    ; until an end of line or non-delimiter is found.
    ; the carry bit is set if and end of line is encountered.

    ; acca, accb, & ix are not preserved

skpdlm:    clc
    tst    bolflg    ; at beginning of line?
    bgt    2$

    ; look at current input character

1$:    ldx    synptr    ; get pointer to it
    lda    ,x    ; get char
    bsr    tsteol    ; test for end of line
    bne    2$
    sec        ; yes, end hit, set carry
    rts

    ; "peek" at next char in line

2$:    ldb    1,x    ; get it
    bsr    tstdlm    ; see if its a delimiter
    bne    3$
    rts        ; if not, return

    ; next char is a delimiter

3$:    jsr    mgetchr    ; move to next char in input line
    stx    synptr    ; update syntax pointer
    bra    1$    ; go test for end of line


    .page
    .sbttl    Test for End-of-Line Character

    ;============================================
    ; test for end-of-line character
    ; z bit of cc reg set if char in acca is a terminator
    ; acca, accb, & ix are preserved

tsteol:    cmpa    #cr    ; carriage return?
    beq    1$
    cmpa    #lf    ; line feed? (continued lines)
    beq    1$
    cmpa    #';    ; for several commands on one line
1$:    rts

    .sbttl    Test for Delimeter

    ;===============================================
    ; check the character n accb aganst the delimiter(s)
    ; specified by variable delim
    ; accb & ix are preserved
    ; acca is set to 0 if accb is not a delimiter, to 1
    ; if it is
    ;  if delim=1, space s delimiter
    ;  if delim=2, comma is delimiter
    ;  if delim=3, space or comma is delimiter
    ;  if delim=4, any non-alphanumeric is a delimiter
    ; test for end-of-line (logical or physical)

tstdlm:    pshs b
    tba
    bsr    tsteol
    puls b
    beq    5$

    lda    delim
    cmpa    #1
    bne    1$
    cmpb    #'     ; want a space - is it?
    bne    6$
    bra    5$

1$:    cmpa    #2
    bne    3$
2$:    cmpb    #',    ; want a comma - is it?
    bne    6$
    bra    5$
3$:    cmpa    #3
    bne    4$
    cmpb    #'     ; want either, is it a space?
    beq    5$
    bra    2$    ; or a comma?

4$:    cmpa    #4
    bne    7$    ; error if delm not 1-4
    cmpb    #'0    ; test if char is 0-9 inclusive
    blt    5$
    cmpb    #'9
    ble    6$

    cmpb    #'A    ; test if char is A to Z inclusive
    blt    5$
    cmpb    #'Z
    ble    6$    ; over Z - its a delimiter

5$:    lda    #1    ; char in accb is a delimiter
    rts

6$:    clra        ; char in accb is not a delimiter
    rts
            ; error in specifying delimiter class
7$:    swi        ; have monitor type out pertinent
            ; statistics

    .page
    .sbttl    Sum Two Numbers

    ;================================================
    ; add the 2 byte number stored in (ranglo,ranglo+1) to
    ; the number stored in (nbrhi,nbrlo) and put the result
    ; in (ranghi,ranghi+1)

sumnum:    pshs    d    ; add lo order bytes
    ldd    ranglo
    addd    nbrhi
    std    ranghi
    puls    d,pc

    .sbttl    Subtract Two Numbers

    ;====================================================
    ; subtract the 2 byte number stored in (nbrhi,nbrlo)
    ; from the two byte number stored in (ranglo,ranglo+1)
    ; and put the result in (ranghi,ranghi+1)
    ; accb & ix are preserved
    ; acca is altered

difnum:    pshs    d    ; subtract lo order bytes
    ldd    ranglo
    subd    nbrhi
    std    ranghi
    puls    d,pc

    .page
    .sbttl    Get Range

    ;===================================================
    ; this routine scans the input line for a pair of numbers
    ; representing an address range. a colon separating the
    ; pair implies "thru", while an "!" implies "thru the
    ; following"
    ; e.g., 100:105 is equivalent to 100!5
    ; a single number implies a range of 1
    ; on return (ranglo,ranglo+1) holds the range start, and
    ; (ranghi,ranghi+1) holds the range end
    ; acca, accb, & ix are not preserved

gtrang:    bsr    mnumber    ; pick up first number
    bgt    1$
    blt    2$
    rts        ; nothing more on input line


1$:    ldx    nbrhi    ; good single number
    stx    ranglo    ; transfer it to ranglo
    bra    3$    ; and to ranghi

    ; bad number, but is it bad due to a ":" or "!" delimiter?
    ; get the terminator for the first number

2$:    ldx    linptr
    lda    ,x
    cmpa    #':    ; was it a colon?
    bne    4$    ; if not, go test for "!"
    bsr    8$    ; was ":", process first number &
            ; get next one
    ble    5$    ; illegal if end of line or non-numeric

3$:    ldx    nbrhi    ; transfer second number to ranghi
    stx    ranghi
    bra    7$

4$:    cmpa    #'!    ; was delimiter a "!"?
    beq    6$    ; if yes, get 2nd number
    clra        ; illegal delimiter, return
    deca
5$:    rts

6$:    bsr    8$    ; was "!", process first number &
            ; get next one
    ble    5$
    bsr    sumnum    ; compute range end, put into ranghi

7$:    lda    #1    ; successful exit
    rts

    ; update syntax pointer, move first number to ranglo,
    ; & get 2nd number

8$:    stx    synptr    ; update syntax pointer
    ldx    nbrhi    ; get first number of the pair
    stx    ranglo    ; save it in "low range" value
    bsr    mnumber    ; pick up the second number of the pair
    rts

    .page
    .sbttl    Get number in IX

    ;====================================================
    ; get a 2 byte number & return it in the index register

numinx:    bsr    mnumber
    bgt    1$
    jmp    badsyn
1$:    ldx    nbrhi
    rts

    .page
    .sbttl    Scan For a Number

    ;==================================================
    ; scan for a number
    ; return the most significant byte in nbrhi
    ; and the least significant byte in nbrlo
    ; the result of the scan for a number is returned in
    ; acca as follows:
    ;
    ;    acca=-1: the match was unsuccessful. the syntax
    ;        pointer (synptr) was not updated.
    ;
    ;    acca= 0: the scan was unsuccessful since there
    ;        were no more characters. (i.e., the end
    ;        of the line was encountered.)
    ;
    ;    acca=+1: the scan was successful. the syntax
    ;        pointer was updated to the first character
    ;        following the command.
    ;
    ; ix is preserved
    ; global variables for external communication
    ; nbrhi - number hi byte
    ; nbrlo - number lo byte
    ; ibcode - input base code
    ; dbcode - display base code
    ;
    ; local variables
    ; nbr2x - used in decimal conversion
    ; initialize both bytes to zero

mnumber:pshs    x    ; save ix
    clr    nbrhi
    clr    nbrlo
    ldx    synptr    ; initialize the line scanning pointer
    stx    linptr
    jsr    skpdlm    ; are we at end of line?
    bcc    1$
    clra        ; yes, zero acca
    puls    x,pc

1$:    jsr    mgetchr    ; get a character from the input
            ; line into accb
    jsr    tstdlm    ; test for a delimiter
    bne    6$    ; good delimiter if acca is non-zero
    subb    #'0    ; subtract ascii 0
    bmi    8$    ; error if less

    lda    ibcode    ; determine input base & go to right routine
    cmpa    #1    ; hex code ?
    beq    2$

    cmpa    #2    ; decimal code ?
    beq    4$

    cmpa    #3    ; octal code ?
    beq    5$

    ; hex input processing

2$:    cmpb    #'9-'0    ; default an illegal input base to hex
    ble    3$    ; if 9 or less
    cmpb    #'A-'0
    bmi    8$    ; not hex if < A
    cmpb    #'F-'0
    bgt    8$    ; not hex if > F
    subb    #7    ; move A-F above 0-9

3$:    bsr    9$    ; shift lo & hi bytes left 4 bits
    bsr    9$
    orb    nbrlo
    stb    nbrlo
    bra    1$

    ; decimal input

4$:    cmpb    #9
    bgt    8$    ; not decimal if > 9

    ; multiply saved value by 10 & add in new digit

    bsr    10$    ; multiply current number by 2 to get 2x value
    ldx    nbrhi    ; save this *2 number temporarily
    stx    nbr2x
    bsr    9$    ; multiply this # by 4 to get 8x value
    clra        ; new digit <a,b>
    addd    nbr2x    ; note that 10x=2x+8x
    bcs    8$    ; carry out of ms byte is an error
    addd    nbrhi
    bcs    8$    ; carry out of ms byte is an error
    std    nbrhi    ; save result
    bra    1$

    ; octal input

5$:    cmpb    #7
    bgt    8$    ; not octal if > 7
    bsr    9$    ; shift hi & lo bytes 3 places left
    bsr    10$    ; carry out of hibyte is illegal
    orb    nbrlo    ; add in new digit
    stb    nbrlo
    bra    1$

6$:    ldx    linptr    ; good number - scan was successful
    stx    synptr    ; update good syntax line pointer
    lda    #1    ; set "good scan" flag
    puls    x,pc

7$:    leas    2,s
8$:    clra        ; conversion error - scan was unsuccessful
    deca
    puls    x,pc

9$:    asl    nbrlo    ; shift a two byte number left one position
    rol    nbrhi
    bcs    7$
10$:    asl    nbrlo    ; shift a two byte number left one position
    rol    nbrhi
    bcs    7$
    rts

    .page
    .sbttl    General Output Routines

    ;===========================================
    ; output a space

outsp:    lda    #'
    jsr    outchr
    rts

    ;===========================================
    ; output an "=" sign

outeq:    lda    #'=
    jsr    outchr
    rts

    ;==========================================
    ; output a 1 byte number

out1by:    pshs    d
    ldb    #1
    bsr    outnum
    puls    d,pc

    ;==========================================
    ; output a 2 byte number

out2by:    pshs    d
    ldb    #2
    bsr    outnum
    puls    d,pc

    ;==========================================
    ; display the number pointed at by the address in the
    ; index register and output it according to the base
    ; specified in "dbcode"
    ; leading zeros are included
    ; acca & ix are preserved
    ; accb is input as the number of bytes comprising the
    ; number.
    ; global variables for external communication
    ; ibcode - input base code
    ; dbcode - display base code
    ;
    ; local variables
    ; decdig - decimal digit being built
    ; numbhi - hi byte of number being output
    ; numblo - lo byte of number being output

outnum:    pshs    d,x    ; save these
    ldx    ,x    ; get the two bytes at that address
    stx    numbhi    ; put them in a scratch area for processing
    lda    dbcode    ; get display base

    cmpa    #1
    beq    1$
    cmpa    #2
    beq    4$
    cmpa    #3
    beq    11$
    cmpa    #4
    beq    14$

    ; output a hex number

1$:    aslb        ; 1 byte=2 chars, 2 bytes=4 chars
2$:    bsr    16$    ; get next 4 bits
    bsr    16$

    anda    #0x0f    ; extract 4 bits
    cmpa    #9
    ble    3$
    adda    #7    ; convert 10:15 to A-F

3$:    bsr    18$
    decb
    bne    2$
    puls    d,x,pc    ; restore registers & return

    ; output a decimal number

4$:    decb        ; test # of bytes to output
    beq    5$
    ldx    #9$    ; initialize for output of a 2 byte number
    ldd    numbhi
    bra    6$

5$:    ldx    #10$    ; initialize for output of a 1 byte number
    clra
    ldb    numbhi
6$:    clr    decdig    ; clear the digit to output
7$:    subd    ,x    ; subtract the power of 10 conversion constant
    bcs    8$    ; test for borrow (carry)
    inc    decdig    ; no borrow yet - nc digit being built
    bra    7$    ; repeat loop

    ; building of digit to output is complete - print it

8$:    pshs    a    ; save lo byte of number being output
    lda    decdig    ; get digit
    bsr    18$    ; print it
    puls    a    ; restore lo byte

    addd    ,x++    ; borrow generated - cancel last subtraction
    cpx    #9$+10    ; are we thru with units conversion?
    bne    6$    ; if not, back to get next digit
    puls    d,x,pc    ; if yes, restore registers & return

    ; decimal output conversion constants

9$:    .word    10000
    .word    1000
10$:    .word    100
    .word    10
    .word    1

    ; output an octal number

11$:    aslb        ; first approximation of # of
    clra        ; digits to output
    cmpb    #2
    bgt    12$
    bsr    16$    ; 1 byte - get first 2 bits
    bsr    18$
    bra    13$    ; go output last 2 digits

12$:    bsr    17$    ; two byte # - output hi order bit/digit
    bsr    18$
    incb        ; 5 more digits to go

13$:    bsr    16$    ; get next 3 bits
    bsr    17$
    anda    #7    ; extract 3 bits
    bsr    18$
    decb        ; count this digit
    bne    13$    ; are we done?
    puls    d,x,pc    ; if yes, restore registers & return

14$:    aslb    ; output a binary number
    aslb
    aslb
15$:    bsr    17$    ; get next bit
    anda    #1    ; extract the bit
    bsr    18$    ; output it
    decb        ; count it
    bne    15$    ; are we done?
    puls    d,x,pc    ; if yes, restore registers & return

16$:    bsr    17$    ; left shift 2 bits

17$:    asl    numblo    ; left shift the 3 byte number 1 bit
    rol    numbhi
    rola
    rts

18$:    adda    #'0    ; convert to a numeric ascii digit & output it
    jsr    outchr
    rts

    .page
    .sbttl    Get Character Routines

    ;=================================================
    ; this routine gets the next character from the input
    ; line buffer
    ; acca is preserved
    ; accb is loaded with the character
    ; ix is incremented and left pointing to the character
    ; returned

mgetchr:
    ldx    linptr
    inx
    ldb    ,x
    stx    linptr
    clr    bolflg    ; set flag to not at "beginning of line"
    rts

    ;==================================================
    ; this routine gets the next character in the command
    ; lists
    ; acca is the character retrieved
    ; accb is preserved
    ; ix is incremented & left pointing to the character returned

getlst:    ldx    lisptr    ; get current list pointer
    inx        ; move pointer to next character
    lda    ,x    ; get character pointed at
    stx    lisptr    ; save pointer
    rts        ; and return

    .page
    .sbttl    Command Lists

    ;=====================================================
    ; command lists
    ;  a carriage return signifies end-of-command
    ;  a line feed signifies end-of-command-list
    ; list 1 - major commands

comlst:    .ascii    /BREAK/        ; set breakpoint (swi code)
    .byte    cr
    .ascii    /CONTINUE/    ; continue from "swi"
    .byte    cr
    .ascii    /COMPARE/    ; print sum & difference of 2 numbers
    .byte    cr
    .ascii    /COPY/        ; copy from one location to another
    .byte    cr
    .ascii    /DISPLAY/    ; display memory data
    .byte    cr
    .ascii    /DBASE/        ; set display base
    .byte    cr
    .ascii    /DELAY/        ; delay specified # of bytes
    .byte    cr
    .ascii    /DUMP/        ; dump memory in mikbug or image format
    .byte    cr
    .ascii    /GOTO/        ; go to memory address
    .byte    cr
    .ascii    /HELP/        ; help listing
    .byte    cr
    .ascii    /IBASE/        ; set input base
    .byte    cr
    .ascii    /LOAD/        ; load mikbug tape
    .byte    cr
    .ascii    /REG/        ; display registers
    .byte    cr
    .ascii    /SET/        ; set memory data
    .byte    cr
    .ascii    /SEARCH/    ; search memory for a byte string
    .byte    cr
    .ascii    /TEST/        ; test a range of memory
    .byte    cr
    .ascii    /VERIFY/    ; verify that memory content is unchanged
    .byte    cr
    .ascii    /CLI/        ; clear interrupt mask
    .byte    cr
    .ascii    /CLF/        ; clear fast interrupt mask
    .byte    cr
    .ascii    /SEI/        ; set interrupt mask
    .byte    cr
    .ascii    /SEF/        ; set fast interrupt mask
    .byte    cr
    .ascii    /IRQ/        ; set interrupt pointer
    .byte    cr
    .ascii    /FIRQ/        ; set fast interrupt pointer
    .byte    cr
    .ascii    /NMI/        ; set non-maskable interrupt pointer
    .byte    cr
    .ascii    /RSRVD/        ; set reserved interrupt pointer
    .byte    cr
    .ascii    /SWI/        ; set software interrupt pointer
    .byte    cr
    .ascii    /SWI2/        ; set swi2 interrupt pointer
    .byte    cr
    .ascii    /SWI3/        ; set swi3 interrupt pointer
    .byte    cr
    .byte    lf        ; end of list 1

    ; list 2 - modifier to dump

    .ascii    /TO/        ; destination
    .byte    cr
    .byte    lf        ; end of list 2

    ; list 3 - number base specifiers

    .ascii    /HEX/        ; base 16
    .byte    cr
    .ascii    /DEC/        ; base 10
    .byte    cr
    .ascii    /OCT/        ; base 8
    .byte    cr
    .ascii    /BIN/        ; base 2
    .byte    cr
    .byte    lf        ; end of list 3

    ; list 4 - information request

    .ascii    /?/
    .byte    cr
    .byte    lf        ; end of list 4

    ; list 5 - register names

    .ascii    /.CC/
    .byte    cr
    .ascii    /.A/
    .byte    cr
    .ascii    /.B/
    .byte    cr
    .ascii    /.DP/
    .byte    cr
    .ascii    /.IX/
    .byte    cr
    .ascii    /.IY/
    .byte    cr
    .ascii    /.IU/
    .byte    cr
    .ascii    /.AB/
    .byte    cr
    .ascii    /.PC/
    .byte    cr
    .ascii    /.SP/
    .byte    cr
    .byte    lf        ; end of list 5

    ; list 6 - modifiers to "display"

    .ascii    /DATA/
    .byte    cr
    .ascii    /USED/
    .byte    cr
    .byte    lf        ; end of list 6

    ; list 7 - modifier to "load"

    .ascii    /FROM/        ; source
    .byte    cr
    .byte    lf        ; end of list 7


    .page
    .sbttl    Get a line

    ;=======================================================
    ;
    ; this routine constructs a line of input by getting all
    ; input characters up to and including a carriage return
    ; (which then designates "end of line").
    ; typing rubout will delete the previous character
    ; typing control-c will abort the line
    ; typing control-z will use the previous line
    ; the input line is stored beginning at the address
    ; stored in bufbeg and ending at the address stored
    ; in bufend
    ; acca, accb, & ix are not preserved
    ;
    ; global variables
    ; bufbeg - input line start of buffer
    ; bufend - input line end of buffer
    ;
    ; local constants

getlin:    ldx    bufbeg    ; set pointer to one less than
            ; the beginning of the line buffer
    clrb        ; accb holds last input char
1$:    cpx    bufend    ; check current line end against buffer end
    bne    2$

    ; line too long - abort it as if a control-c had been typed

    ldx    #msgltl    ; get message
    jsr    outstr    ; output it
    ldb    #3    ; put ctl-c in accb
    rts

2$:    jsr    inpchr    ; get a character (returned in acca)
    anda    #0x7f    ; drop parity bit

    ; control-z copies from present position to previous end of line

    cmpa    #26    ; is char a control-z?
    bne    3$
    jsr    docrlf    ; yes, type cr-lf
    rts

3$:    cmpa    #13    ; is char a cr?
    beq    4$
    cmpa    #10    ; or a lf?
    bne    6$
4$:    inx
    sta    ,x    ; yes, store the terminator
    tst    hdxflg    ; test for half-duplex terminal
    bne    5$
    jsr    docrlf    ; type cr-lf
5$:    rts        ; now return

6$:    cmpa    #3    ; is char a control-c?
    bne    7$    ; no
    tab        ; return ctl-c in accb
    lda    #'^    ; echo an up-arrow
    jsr    outchr
    rts

7$:    cmpa    #127    ; no, is it delete?
    beq    10$    ; yes - delete character
    inx        ; not a delete, so advance to next char
    sta    ,x    ; store it in inplin
    tab        ; last character in b
    tst    hdxflg    ; check half duplex
    bne    9$    ; yes - skip
    jsr    outchr    ; echo character
9$:    bra    1$    ; get another

    ; current character is a delete
    ; test line length - if its zero, ignore this delete
    ; since we can't delete prior to first char in input line

10$:    cpx    bufbeg
    beq    1$
    pshs    x
    ldx    #11$    ; delete character on screen
    bsr    outstr
    puls    x
    ldb    ,-x    ; last character
    bra    1$

11$:    .byte  8,32,8,4    ; BS, SPACE, BS, EOT


    ;====================================================
    ; initialization routine

inital:    lda    #1
    sta    ibcode    ; set input base to hex
    sta    dbcode    ; set display base to hex

    ; set up display base number

    lda    #16
    sta    dbnbr

    ; max # of characters per line

    lda    #72
    sta    cplmax
    clr    inpflg    ; default input from terminal
    clr    outflg    ; default output to terminal
    clr    hdxflg    ; clear    half-duplex flag

    ; set up swi interrupt address pointer

    ldx    #typswi    ; type "swi" & do "reg" command
    stx    .swi

    ; clear breakpoint address

    ldd    #0xfffe    ; normal systems have rom here
    std    brkadr

    ; initialize to mondeb's command lists

    ldx    #comlst-1
    stx    comadr

    ; time constant for a .5 microsecond clock

    ldd    #285
    std    timcon

    .if    inituser
    jmp    userinit    ; user returns via rts
    .else
    rts
    .endif

    ;===================================================
    ; output a character string which begins at the address
    ; in the index register
    ; acca & accb are preserved
    ; ix is left pointing to the string terminator

outstr:    pshs    a
1$:    lda    ,x    ; get char pointed to
    cmpa    #4    ; is it a string terminator?
    beq    2$    ; done if it is
    bsr    outchr    ; isn't, output it
    inx        ; on to next char
    bra    1$
2$:    puls    a,pc

    ;=====================================================
    ; input a character

inpchr:    tst    inpflg    ; console ?
    bne    2$

1$:    jsr    [conin]    ; tst for a character
    bcc    1$    ; none - loop until there is
    rts

2$:    jsr    [altin]    ; tst for a character
    bcc    2$    ; none - loop until there is
    rts

    ;======================================================
    ; output the character in acca to the desired output
    ; device/location
    ; if outflg = 0, output is to terminal
    ; if outflg # 0, output is to address in outadr
    ;    & this address is then incremented

outchr:    pshs    d,x    ; save d and x
    ldb    outflg    ; test output destination flag
    decb
    ble    1$    ; skip this code if terminal output

    ; output to something other than terminal

    ldx    outadr    ; get output char destination addr
    sta    ,x+    ; save char in memory
    stx    outadr    ; update output address
    puls    d,x,pc

1$:    cmpa    #lf    ; ignore line feeds
    bne    2$
    puls    d,x,pc

2$:    cmpa    #cr    ; test for carriage return
    bne    3$
    bsr    docrlf
    puls    d,x,pc

3$:    ldb    cplcnt    ; get "chars per line" count
    cmpb    cplmax
    bge    4$    ; send cr-lf if greater

    ; less than max, but also send cr-lf if 10 from end and
    ; printing a space

    addb    #10
    cmpb    cplmax
    blt    5$
    cmpa    #'     ; near end, test if about to print a space
    bne    5$

    ; terminal line full or nearly full - interject a cr-lf

4$:    bsr    docrlf
5$:    inc    cplcnt    ; bump counter
    bsr    chrout    ; send it to acia1
    puls    d,x,pc

    ;======================================================
    ; send a carriage return-line feed to the terminal

docrlf:    pshs    d
    lda    #cr
    bsr    chrout
    lda    #lf
    bsr    chrout
    clr    cplcnt    ; zero "chars/line" count
    puls    d,pc

    ;======================================================
    ; send char in acca

chrout:    tst    outflg    ; check destination
    bne    1$
    jmp  [conout]    ; output a character
1$:    jmp  [altout]

    ;======================================================
    ; misc text

msghed:    .ascii    /MONDEB-09 1.00/
    .byte    cr,4
msgprm:    .byte    '*,4
msgswi:    .byte    cr,lf
    .ascii    /swi:/
    .byte    cr,lf,4
msgltl:    .ascii    /too long/
    .byte    4
msgnbr:    .ascii    /not set/
    .byte    4
msgbat:    .ascii    /set @ /
    .byte    4
msgver:    .ascii    /ok/
    .byte    4
msgnve:    .ascii    /checksum error /
    .byte    4
msgccl:    .ascii    /can't clear/
    .byte    4
msgcso:    .ascii    /can't set to ones/
    .byte    4
msgsis:    .ascii    /sum is /
    .byte    4
msgdis:    .ascii    /, dif is /
    .byte    4
msgs1:    .byte    cr,lf,0,0,'S,'1,4
msgs9:    .byte    cr,lf,0
    .ascii    /S9030000FC/
    .byte    cr,lf,4
msgcnh:    .ascii    /char not hex/
    .byte    cr,4


    ;****************************************************
    ;*            default interrupt transfers           *
    ;****************************************************

    .if    standalone
rsrvd:    jmp    [.rsrvd]    ; reserved vector
swi3:    jmp    [.swi3]        ; swi3 vector
swi2:    jmp    [.swi2]        ; swi2 vector
firq:    jmp    [.firq]        ; firq vector
irq:    jmp    [.irq]        ; irq vector
swi:    jmp    [.swi]        ; swi vector
nmi:    jmp    [.nmi]        ; nmi vector
    .endif

    .page
    .sbttl    dispatch table

    .if    standalone

    .area    DISPAT    (REL,CON)

    .word    timdel    ; time delay for # of ms specified by ix
    .word    cksum    ; return checksum of an address range in acca
    .word    mgetchr    ; return (in accb) char pointed to by linptr
    .word    getlst    ; return (in acca) char pointed to by lisptr
    .word    gtrang    ; pick up an address range in ranglo & ranghi
    .word    mnumber    ; pick up a number & return it in nbrhi & nbrlo
    .word    skpdlm    ; skip over input line delimiters
    .word    tstdlm    ; test char in accb for a delimiter
    .word    tsteol    ; test char in acca for end-of-line
    .word    comand    ; search specified command list for a command
    .word    typcmd    ; types out command number "comnum" in list acca
    .word    out1by    ; display the 1 byte number pointed at by ix
    .word    out2by    ; display the 2 byte number pointed at by ix
    .word    getlin    ; get a line of input into the tty buffer
    .word    outstr    ; output char string ix points to
    .word    docrlf    ; send cr-lf with delay & zero line count
    .word    outchr    ; like chrout, but with folding, cr delay, & lf
    .word    chrout    ; send acca to console
    .word    inpchr    ; get a char, return it in acca
    .word    prompt    ; to prompt for new command
    .word    mond09    ; start of mondeb
    .endif

    .page
    .sbttl    Hardware Interrupt Tables

    ;********************************************************
    ;*             MONDEB-09 hardware vector table
    ;*
    ;*  this table is used if the MONDEB-09 rom addresses
    ;*  the mc6809 hardware vectors.
    ;********************************************************

    .if    standalone

    .area    INTVEC    (ABS,OVR)

    . = 0xFFF0        ; vector position

    .word    rsrvd        ; reserved slot
    .word    swi3        ; software interrupt 3
    .word    swi2        ; software interrupt 2
    .word    firq        ; fast interrupt request
    .word    irq        ; interrupt request
    .word    swi        ; software interrupt
    .word    nmi        ; non-maskable interrupt
    .word    reset        ; restart
    .endif