;***************************************************************************** ; ; Flop2PC - Transfer floppy image to PC over a serial port ; for North Star Horizon Computer (single density FDC) ; ; This program transmits an image of a North Star single density floppy ; to a PC over a serial port using the XMODEM protocol. The disk is ; copied in raw format (256 bytes per sector, 10 sectors per track, ; 35 tracks). The disk image is the linear sequence of the ; 256 byte sectors from track 0, sector 0 through track 34, ; sector 9. The leading zeros before the data payload and the checksum ; are not transferred. ; ; This program runs standalone at 0x100 or under CP/M. ; ; Written by Mike Douglas ; ; Rev Date Desc ; 1.0 11/15/15 Original ; ;***************************************************************************** ; Disk information equates NUMTRK equ 35 ;number of tracks NUMSEC equ 10 ;number of sectors per track SECLEN equ 256 ;sector length (as transmitted) MINDRV equ 1 ;first drive number MAXDRV equ 3 ;max drive number TRKLEN equ (NUMSEC*SECLEN) ;length of track in bytes DKTRIES equ 5 ;number of disk read retries ; Monitor, CP/M boot entry points MONITOR equ 0100h ;no default ROM, just restart program CPMBOOT set 0e900h ;cold boot ROM entry point ; XMODEM equates PKTLEN equ 128 ;128 byte xmodem packet length SOH equ 001h EOT equ 004h ACK equ 006h NAK equ 015h EOF equ 01ah ;ctrl-z character XMTRIES equ 10 ;number of xmodem retries ; CP/M Equates WBOOT equ 0 ;warm boot jump location ; Misc equates CR equ 13 ;ascii for carriage return LF equ 10 ;ascii for line feed DEL equ 7fh ;ascii DEL BS equ 08h ;ascii backspace CTRLC equ 03 ;ascii for control-c JMPINST equ 0c3h ;jump instruction opcode org 0100h ;load address ;----------------------------------------------------------------------------- ; Initialize for transfer ;----------------------------------------------------------------------------- init lxi sp,ourStk ;initialize stack pointer call chkCpm ;set flag for CP/M or not call sizeRam ;determine amount of RAM available mvi a,MINDRV ;a=default drive sta drvNum ;need for pgmExit ; Display welcome message, then get the drive number and port number ; to use for the transfer from the operator. lxi h,mWelcom ;display welcome message call dispMsg ; getDrv - get drive number or letter from the user. getDrv lxi h,mDrive ;display drive number prompt call dispMsg call rcvCon ;get byte from the console ori 20h ;upper case letters to lower case cpi 'x' ;exit requested? jz pgmExit ;yes lxi h,baseDrv ;ascii 1st drive - baseDrv = 0 sub m jm getDrv ;error, entry was < first drive cpi MAXDRV-MINDRV+1 ;validate <= max drive jnc getDrv ;invalid, prompt again adi MINDRV ;restore offset of 1st drive (if any) sta drvNum ;save the drive number to use ; getPort - get serial port number 1-2 from the user. getPort lxi h,mPort ;display transfer port prompt call dispMsg call rcvCon ;get byte from the console ori 20h ;upper to lower case, nums not affected cpi 'x' ;exit requested? jz pgmExit ;yes sui '1' ;'1' to 0 cpi 2 ;validate input was '1' or '2' jnc getPort ;invalid, prompt again sta xfrPort ;save the port to use ; Prompt the user to start the XMODEM receive operation on the PC. ; Wait for a clear receive line for a least one second, then start ; looking for NAK or 'C' (crc protocol) from the PC lxi h,mStart ;display start file transfer prompt call dispMsg clrRcv1 call rcvByte ;loop until input clear for 1 second jnz clrRcv1 xra a ;set CRC flag to false (checksum mode) sta crcFlag waitNak call chkQuit ;give user chance to abort call rcvByte ;wait for a character cpi NAK jz haveNak ;have a NAK, use checksum protocol cpi 'C' ;CRC protocol requested? jnz waitNak ;no sta crcFlag ;set crc flag non-zero = CRC mode ; NAK or 'C' received meaning the XMODEM receive has started. Initialize ; for the transfer. haveNak mvi a,0ffh ;track position on drive not known sta curTrk xra a ;init track we want to zero sta trkNum inr a ;init xmodem block number to one sta blkNum lxi h,trkBuf ;trkBuf is initial starting point for shld sndPtr ; XMODEM send ;----------------------------------------------------------------------------- ; mainLp - Loop through all tracks on the disk buffering as many tracks ; as will fit in RAM before sending via xmodem, then repeat. ;----------------------------------------------------------------------------- mainLp lxi h,trkBuf ;disk buffering always start at trkBuf shld trkPtr ; Read and buffer bufTrks tracks unless all tracks on drive reached first bufLoop call readTrk ;read into trkBuf lda trkNum ;increment track number (preserve HL) inr a sta trkNum cpi NUMTRK ;done all tracks on the disk? jz sendBuf ;yes, go send the buffered tracks lda trkErr ;read failure on the track? ora a ;if so, send buffered tracks now jnz sendBuf ;so XMODEM won't time out xchg ;de=current track pointer lhld bufEnd ;hl=end of buffering space call cmpDeHl ;compare current-end jc bufLoop ;still room, keep going ; Track buffer is full or all tracks have been read. Send the buffered ; tracks via xmodem. sendBuf call sndTrks ;send the buffered tracks via xmodem lda trkNum ;a=current track cpi NUMTRK ;done all tracks? jnz mainLp ;no, not done yet ; The entire disk has been read and (mostly) transmitted. See if there are ; left over bytes to send. If so, send them. mov a,l ;hl->next packet to send, a=lsb of ptr cpi trkBuf AND 0ffh ;pointing to lsb of address of trkBuf? jz noExtra ;same, no extra bytes to send call sndPkt ;otherwise, send one last packet ; Send EOT and wait for response. Then display the success message and ; start the program over. noExtra call sndEot ;send and get response for EOT lxi h,mDone ;print the all done message call dispMsg jmp getDrv ;start over asking for a drive ;----------------------------------------------------------------------------- ; readTrk - read NUMSEC sectors from the current track into a trkBuf as ; pointed to by trkPtr. After the track is read, trkPtr is updated ; by the length of a track to point to the next track buffer. This ; saved value is also returned in HL. ;----------------------------------------------------------------------------- readTrk lxi h,trkNum ;get desired track from trkNum mov l,m ;and put into l call dSeek ;seek to the track xra a sta trkErr ;no error on this track yet sta rtStep ;current retry step mvi d,NUMSEC ;d=sector counter ; secLoop - Read an entire track. Start at whatever sector comes up next secLoop call chkQuit ;check for ctrl-c call dNxtSec ;wait for next (any) sector sync lhld trkPtr ;hl->start of current track buffer dad b ;bc has offset of sector within track call dRead ;read the sector jnz secRtry ;error, go to retry logic ; Decrement sector count. If full track is done, increment trkPtr ; to point to the next track buffer in trkBuf nxtSec dcr d ;decrement sector count jnz secLoop lhld trkPtr ;hl=current track pointer lxi d,TRKLEN ;de=bytes in a track dad d ;hl=start of next track in trkBuf shld trkPtr ret ;-------------------------------------------------------------------------- ; secRtry - read error retry logic. Six retry steps are tried in ; the following order: ; ; Step Action ; 0 Re-read DKTRIES times ; 1 Seek in one track and back, then re-read DKTRIES times ; 2 Seek out to track 0 and back, then re-read DKTRIES times ; 3 Seek in one track and back, then re-read DKTRIES times ; 4 Seek out to track 0 and back, then re-read DKTRIES times ;-------------------------------------------------------------------------- secRtry mvi a,DKTRIES ;init disk retry counter sta dskRtry retryLp call chkQuit ;check for ctrl-c call dWtSec ;wait for sector specified in e lhld trkPtr ;hl->start of current track buffer dad b ;bc has offset of sector within track call dRead ;read the sector jz rtDone ;success, retries done ; read failed. Decrement retry count and try again if not zero. Once ; retry counter expires, increment the step counter to try the ; next retry stage. lxi h,dskRtry ;decrement retry counter dcr m jnz retryLp ;try again ; read re-tries expired, try next retry step lxi h,rtStep ;move to next retry step inr m mov a,m ;a=new retry step dcr a ;step 1, seek past track and come back jz skPast dcr a ;step 2 restore to track zero jz restor0 dcr a ;step 3, seek past track and come back jz skPast dcr a ;step 4 restore to track zero jz restor0 ; retries failed. Display the error, wait for the failed sector number ; to come under the head again, then jump back into the main ; read loop which will resume at the next sector. call dspErr ;give up, display the error call dWtSec ;wait for the failed sector number ; rtDone - retry logic is done. Reset the retry step counter and ; jump to end of sector processing above rtDone xra a ;restart retry step counter sta rtStep jmp nxtSec ;----------------------------------------------------------------------------- ; restor0 - retry step to restore to track zero, then seek back to ; the current track. ; ; skPast - retry step to seek past the current track, then back to ; the current track. ;----------------------------------------------------------------------------- restor0 push d ;save sector count and number call dRestor ;restore to track zero reseek lxi h,trkNum ;get desired track from trkNum mov l,m ;and put into l call dSeek ;seek back to the track pop d ;restore sector in e jmp secRtry ;try again skPast lda trkNum ;a=current track cpi NUMTRK-1 ;at max track? jz restor0 ;yes, just try restore again push d ;save sector count and number inr a ;otherwise step in a track mov l,a call dSeek jmp reseek ;then back out ;----------------------------------------------------------------------------- ; sndTrks - send the tracks buffered in trkBuf via xmodem. trkPtr points ; to the end+1 of the data to send ;----------------------------------------------------------------------------- sndTrks lhld trkPtr ;hl=end of buffered data + 1 xchg ;de=end of buffered data + 1 lhld sndPtr ;hl=start tranmission address sndLoop push d ;save end pointer call sndPkt ;send a packet pop d ;de=end pointer ; At this point, hl->start of next packet and de->last byte read from disk+1. ; If the next XMODEM packet will go past the end of the disk data, ; we don't want to send it yet. lxi b,PKTLEN ;bc=length of XMODEM packet dad b ;hl=address at end of NEXT packet + 1 call cmpDeHl ;compare disk end - end of next packet jc sndDone ;next packet will pass the end, stop lxi b,-PKTLEN ;restore hl dad b jmp sndLoop ; sndDone - all the packets we can send have been sent. Move any bytes ; left over to just before the start of trkBuf. The next group of ; xmodem packets will be transmitted starting there. sndDone call subDeHl ;hl=de-hl = left over byte count - PKTLEN mov a,l ;a=left over count - PKTLEN adi PKTLEN ;a=left over byte count mov b,a ;b=count of bytes to move lxi h,trkBuf ;hl->start of trkBuf jz mvDone ;no bytes to move, we're done ; Copy the leftover data backwards to just before the track buffer. The ; next XMODEM send sequence will start at the beginning of this copied ; data instead of at the start of trkBuf. moveLp dcx h ;hl->memory just before trkBuf dcx d ;de->unsent bytes from end of trkBuf ldax d ;move from end of trkBuf to before trkBuf mov m,a dcr b jnz moveLp mvDone shld sndPtr ;save address from which to send next time ret ;----------------------------------------------------------------------------- ; sndPkt - send an xmodem format 128 byte packet. HL points to the 128 byte ; buffer to send. On exit, HL points to the next 128 byte boundary. ;----------------------------------------------------------------------------- sndPkt mvi a,XMTRIES ;init retry counter sta xmRetry ; First, send header bytes reSend call chkQuit ;check for ctrl-c push h ;save hl for possible re-send mvi a,SOH ;1st byte is SOH call sndByte lda blkNum ;2nd byte is the block number call sndByte cma ;2nd complement of block number call sndByte ; Init checksum and CRC and packet length for transmission of data portion xra a ;init crc sta crc16 sta crc16+1 lxi d,PKTLEN*256 ;d=byte counter, e=0 (checksum) ; Loop sending the data bytes and updating checksum and CRC pktLoop mov a,m call sndByte ;send and update checksum in e call calCrc ;update the CRC inx h ;point to next byte dcr d ;decrement bytes remaining jnz pktLoop ; Send checksum or CRC based on crcFlag lda crcFlag ;crc or checksum? ora a jz sndCsum ;flag clear = checksum lda crc16+1 ;a=high byte of CRC call sndByte ;send it lda crc16 ;a=low byte of crc jmp sndSkip ;skip next instruction sndCsum mov a,e ;send the checksum byte sndSkip call sndByte ; All bytes sent. Wait for the response. call rcvByte ;get the response character jz sndFail ;timeout on response cpi ACK ;ack received? jnz sndFail ;no, send failed lda blkNum ;increment block number inr a sta blkNum pop b ;remove pushed hl, but don't clobber hl ret ; sndFail - ACK not received, decrement retry and try again. sndFail lxi h,xmRetry ;point to retry counter dcr m jz xmFail ;retries used up, failed xmodem transfer ; If we've had 3 NAKs on the 1st packet and CRC is selected, assume ; we took so long to send the 1st packet due to disk retries that ; the receiver has since timed out and switched to checksum lda crcFlag ;are we in CRC mode jz clrRcv2 ;no, ignore the rest of this lda blkNum ;on block 1? dcr a jnz clrRcv2 ;no, go on lda xmRetry ;failed three times in a row on block 1? sui XMTRIES-3 jnz clrRcv2 ;no sta crcFlag ;clear crcFlag to force checksum ; clrRcv2 - wait for one second of line clear time and send packet again. clrRcv2 call rcvByte ;wait for 1 second of clear line jnz clrRcv2 pop h ;restore pointer to the packet jmp reSend ;re-send the packet ; xmFail - Display failure message then restart program xmFail lxi h,mXmdm ;xmodem failure message call dispMsg lxi sp,ourStk ;initialize stack pointer jmp getDrv ;start over asking for drive ;----------------------------------------------------------------------------- ; calCrc - update the 16-bit CRC with one more byte. ; (Copied from M. Eberhard) ; On Entry: ; a has the new byte ; crc16 is current except this byte ; On Exit: ; crc16 has been updated ; Trashes a,bc ;----------------------------------------------------------------------------- calCrc push d push h lhld crc16 ;get CRC so far xra h ;XOR into CRC top byte mov h,a lxi b,1021h ;bc=CRC16 polynomial mvi d,8 ;prepare to rotate 8 bits ; do 8 bit shift/divide by CRC polynomial cRotLp dad h ;16-bit shift jnc cClr ;skip if bit 15 was 0 mov a,h ;CRC=CRC xor 1021H xra b mov h,a mov a,l xra c mov l,a cClr dcr d jnz cRotLp ;rotate 8 times ; save the updated CRC and exit shld crc16 ;save updated CRC pop h pop d ret ;----------------------------------------------------------------------------- ; sndEot - send EOT character and wait for ACK response ;----------------------------------------------------------------------------- sndEot mvi a,XMTRIES ;init retry counter sta xmRetry reEot mvi a,EOT ;send the EOT call sndByte call rcvByte ;wait for response jz eotFail ;timeout cpi ACK ;ack received? jnz eotFail ;no, eot send failed ret ;otherwise, we're done. ; timeout waiting for ACK to EOT. Decrement retry counter and try again eotFail lxi h,xmRetry ;point to retry counter dcr m rz ;just give up - xfer was probably good clrRcv3 call rcvByte ;wait for 1 second of clear line jnz clrRcv3 jmp reEot ;try again ;----------------------------------------------------------------------------- ; dispMsg - display the null-terminated message passed in hl on the ; console device. Clobbers b, hl ;----------------------------------------------------------------------------- dispMsg mov a,m ;get the next message byte ora a ;null terminates rz mov b,a ;conOut wants character in b call conOut inx h ;move to next byte jmp dispMsg ;----------------------------------------------------------------------------- ; rcvCon - Receive a character from the console device, echo it, then ; wait for a CR. Exits program if Ctrl-c typed. Returns with invalid ; character (null) if BS or DEL pressed after 1st character ; Returns character in a, clobbers b. ;----------------------------------------------------------------------------- rcvCon call conIn ;check for input jz rcvCon ;nothing ani 7fh cpi CTRLC ;abort requested? jz pgmExit ;yes cpi CR ;return pressed? rz ;yes, don't echo it mov b,a ;conOut needs character in b call conOut ;echo it ; Wait for CR, then return 1st character typed rcvCr call conIn ;check for input jz rcvCr ;nothing ani 7fh cpi CTRLC ;abort requested? jz pgmExit ;yes cpi DEL ;delete rz ;yes, return DEL character cpi BS ;backspace? rz ;yes, return BS character cpi CR ;return pressed? jnz rcvCr ;no, keep waiting mov a,b ;return 1st character typed ret ;----------------------------------------------------------------------------- ; sndByte - send the byte in a through the specified transfer port. ; Adds the byte to register e for checksum. Clobbers b. ; XMODEM send routine assumes serOut returns with a containing ; the character sent. ;----------------------------------------------------------------------------- sndByte mov b,a ;b=byte to transmit add e ;update checksum mov e,a ;e=updated checksum lda xfrPort ;a=port to use for transfer jmp serOut ;send the character ;----------------------------------------------------------------------------- ; rcvByte - Receive a byte from specified transfer port with a one second ; timeout. If a timeout occurs, zero is returned in a and the zero ; flag is true. Otherwise, the character is returned in a (could be ; zero) and zero flag is false. ONESEC must be set based on processor ; speed and the number of cycles in the serIn call + 59. ; Clobbers a, b and c. ;----------------------------------------------------------------------------- rcvByte lxi b,ONESEC ;bc=cycles through this loop for 1s rcvWait lda xfrPort ;(13) a=port to use for transfer call serIn ;(17+cycles in serIn)look for a byte rnz ;(5)byte received dcx b ;(5)otherwise, decrement timer mov a,b ;(5)one second expire? ora c ;(4) jnz rcvWait ;(10)no, keep waiting ret ;return with timeout (zero true and in a) ;----------------------------------------------------------------------------- ; dspErr - display the current track and sector number which just had ; a read error. If this is the first error on a track, the track ; number is displayed first. ; ; on entry: ; e = sector number ;----------------------------------------------------------------------------- dspErr lda trkErr ;test track error flag ora a jnz dspSec ;track already displayed, go display sector inr a ;set track flag non-zero sta trkErr ; First error on this track. Display "Track xx errors: " lxi h,errTrk ;hl->where to put ascii decimal lda trkNum ;a=track with error on it call bin2dec ;track to ascii lxi h,mTrkErr ;display the track error message call dispMsg ; dspSec - display the sector number with an error dspSec lxi h,errSec ;hl->where to put ascii sector mov a,e ;a=sector where error occured call bin2dec call dispMsg ;display the error ret ;-------------------------------------------------------------- ; bin2dec - Binary byte in A to 2 ASCII digits at (HL) ; HL is preserved ;-------------------------------------------------------------- bin2dec mvi m,' ' ;assume zero supression sui 10 ;value less than 10? jc do1s ;yes, leading blank mvi m,'1' ;have one ten already loop10 sui 10 ;count 10s jc do1s ;done with 10s, do 1s inr m jmp loop10 do1s adi '0'+10 ;form ASCII 1s digit inx h ;move to 1s position mov m,a dcx h ;restore hl ret ;-------------------------------------------------------------- ; chkQuit - check for the user to request abort (ctrl-c). If ; a character is present on the console port, read it and ; see if ctrl-c. Clobbers A ;-------------------------------------------------------------- chkQuit call conIn ;check for console input rz ani 7fh cpi CTRLC ;abort requested? rnz ;no ; Ctrl-C typed while program is running. Return to drive prompt. lxi sp,ourStk ;initialize stack pointer jmp getDrv ;start over asking for drive num ;-------------------------------------------------------------- ; pgmExit - Exit to CP/M or to the monitor ROM based on the ; CP/M flag ;-------------------------------------------------------------- pgmExit lda cpmFlag ;running under CP/M? ora a jnz cpmExit ;yes ; Exit to ROM monitor lxi h,mExit ;display "exiting" message call dispMsg jmp MONITOR ;jump to ROM monitor entry point ; CP/M exit. If boot drive was used, prompt user to insert CP/M disk cpmExit lda drvNum ;boot drive used? sui MINDRV jnz noDisk ;not 1, disk prompt not needed lxi h,mCpm ;display "insert cp/m disk" call dispMsg call rcvCon ;wait for a character noDisk lxi h,mExit ;display "exiting" message call dispMsg jmp CPMBOOT ;reboot CP/M ;-------------------------------------------------------------- ; chkCpm - check if running under CP/M. CP/M flag is set true ; (non-zero) if yes, cleared otherwise. ;-------------------------------------------------------------- ; First, initialize entries for stand-alone chkCpm xra a sta cpmFlag ;clear CP/M flag mvi a,MINDRV+'0' ;ascii for minimum drive number sta mDrvMin ;store in the drive prompt message sta baseDrv ;ascii 1st drive - baseDrv = 0 mvi a,MAXDRV+'0' ;ascii for max drive number sta mDrvMax ; Determine if we're under CP/M or standalone. CP/M is assumed if ; a jump instruction is present at the CP/M warm start location (0) ; and five more jumps (e.g., a jump table) is present at the ; jump-to destination. lda WBOOT ;see if jump instruction present for CP/M cpi JMPINST rnz ;no, not CP/M ; A jump instruction is present at the CP/M warm boot location (0), ; now see if that jump points to five more jumps. If so, assume CP/M lxi h,WBOOT+1 ;point to lsb of jump address mov e,m ;e=low byte of jump inx h mov d,m ;de=destination of jump mvi b,5 ;look for 5 more jumps (a jump table) jmpTest ldax d ;a=opcode at jump destination sui JMPINST ;another jump present? rnz ;no, not CP/M inx d ;move to next jump inx d inx d dcr b jnz jmpTest dcr a ;a=0ffh sta cpmFlag ;CP/M flag to non-zero = true ; We're running under CP/M. Change drive prompt message to show drive ; letters instead of drive numbers and change baseDrv to convert ; an 'A' to the base drive number (MINDRV). mvi a,'A' ;'A' in drive message instead of number sta mDrvMin adi MAXDRV-MINDRV ;max drive letter sta mDrvMax mvi a,'a' ;ascii 1st drive - baseDrv = 0 sta baseDrv ret ;------------------------------------------------------------------ ; sizeRam - determine how much RAM we have for buffering tracks. ; Sets the bufEnd variable which points to end address of ; the last possible track buffer + 1 ;------------------------------------------------------------------ sizeRam lxi h,(trkBuf+0ffh) AND 0ff00h ;next 256 byte boundary ramLoop mov a,m ;a=current RAM content inr m ;change RAM cmp m ;did RAM change? mov m,a ;restore RAM jz ramEnd ;end of RAM found inr h ;next page jnz ramLoop ; ramEnd - end of RAM found. Now determine the end address + 1 of the ; last track buffer that will fit in RAM. Store in bufEnd ramEnd xchg ;de=end of RAM + 1 mvi a,-((TRKLEN SHR 8) + 1) AND 0ffh cmp d ;force de < (10000h - TRKLEN) jnc topOk mov d,a ;limit max address topOk lxi h,trkBuf ;hl=start of track buffer lxi b,TRKLEN ;bc=length of track in bytes ; Loop increasing hl by TRKLEN until hl > end of RAM. bfEndLp dad b ;hl=hl+track length call cmpHlDe ;compare hl-de jc bfEndLp ;still more room, keep going ; Subtract one track length from hl, this will be the end address + 1 of ; the the last track buffer that will fit in RAM lxi b,-TRKLEN ;subtract one track length dad b ;hl = end address of last track + 1 shld bufEnd ;save as bufEnd ret ;-------------------------------------------------------------------- ; cmHlDe - compare HL-DE. Carry set if HL=DE ;-------------------------------------------------------------------- cmpHlDe mov a,l ;compare HL-DE, do lsbs first sub e mov a,h ;do msbs sbb d ret ;carry set HL=DE ;-------------------------------------------------------------------- ; cmDeHl - compare DE-HL. Carry set if DE=HL ;-------------------------------------------------------------------- cmpDeHl mov a,e ;compare DE-HL, do lsbs first sub l mov a,d ;do msbs sbb h ret ;carry set DE=HL ;-------------------------------------------------------------------- ; subDeHl - HL=DE-HL ;-------------------------------------------------------------------- subDeHl mov a,e ;subtract DE-HL, do lsbs first sub l mov l,a ;lsb result in l mov a,d ;do msbs sbb h mov h,a ;msb result in h ret ;--------------------------------------------------------------------- ; Message constants ;--------------------------------------------------------------------- mWelcom db cr,lf,lf db '===== Floppy to PC Image Transfer (SD Horizon), v1.0 =====' db cr,lf,lf db 'This program transfers an image of a North Star single' db cr,lf db 'density disk to a PC through a user-specified port' db cr,lf db 'using the XMODEM protocol (checksum or CRC).',0 mDrive db cr,lf,lf,'Insert and specify source drive (' mDrvMin db 'x-' mDrvMax db 'x) or X to exit: ',0 mNoType db cr,lf,lf,'** Disk type could not be determined **',0 mSgl db cr,lf,lf,'** Single sided disk detected **',0 mDbl db cr,lf,lf,'** Double sided disk detected **',0 mType db cr,lf,lf db 'Transfer a single or double sided disk?',cr,lf db ' 1) Single Sided',cr,lf db ' 2) Double Sided',cr,lf db 'Choose disk type or X to exit: ',0 mPort db cr,lf,lf db 'Specify the serial port to use for file transfer',cr,lf db ' 1) Console serial port',cr,lf db ' 2) Second serial port',cr,lf db 'Enter port or X to exit: ',0 mStart db cr,lf,lf,'Start XMODEM receive operation on the PC now...',0 mDone db cr,lf,lf,'Transfer complete!',cr,lf,0 mXmdm db cr,lf,lf,'XMODEM communication failure',cr,lf,0 mNoTrk0 db cr,lf,lf,'Seek to track 0 failed',cr,lf,0 mStkTk0 db cr,lf,lf,'Drive stuck on track 0',cr,lf,0 mNotRdy db cr,lf,lf,'Drive not ready',cr,lf,0 mTrkErr db cr,lf,'Track ' errTrk db 'xx failed sectors: ',0 errSec db 'xx ',0 mExit db cr,lf,lf,'Exiting...',cr,lf,0 mCpm db cr,lf,lf db 'Insert CP/M disk into drive A, then press Return...',0 ;**************************************************************************** ; ; Hardware specific console and serial I/O routines. ; The following four routines must be written to provide a common ; interface to the hardware on which this program is running. The ; port number specified for serIn and serOut matches the port number ; input from the operator via the port menu. ; ;**************************************************************************** ; 8251 UART Equates SIOACR equ 03h ;console port - control register SIOADR equ 02h ;console port - data register SIOBCR equ 05h ;2nd port - control register SIOBDR equ 04h ;2nd port - data register SIORDA equ 02h ;read data available flag SIOTRE equ 01h ;transmit register empty flag ; The rcvByte subroutine above times a one second timeout with a code ; loop that calls the hardware specific serIn routine below. ONESEC ; must be set based on processor speed and the number of cycles in ; the serIn call + 59 cycles for the rcvByte code. ONESEC equ 39604 ;rcvByte loop count for 1 second (4mhz) ;---------------------------------------------------------------------------- ; conIn - input character from console ; inputs: ; outputs: z true if no character present ; z false if character returned in a ; clobbers none ;---------------------------------------------------------------------------- conIn in SIOACR ;see if a new character is present ani SIORDA rz ;no character, return zero status in SIOADR ;return character and non-zero status ret ;---------------------------------------------------------------------------- ; conOut - output character to console ; inputs: b = character to send ; clobbers a ;---------------------------------------------------------------------------- conOut in SIOACR ;wait for OK to transmit ani SIOTRE jz conOut mov a,b ;a=character to transmit out SIOADR ;send it ret ;---------------------------------------------------------------------------- ; Hardware specific I/O ; serIn - input character from port specified in a ; 0 = console serial port ; 1 = second serial port ; inputs: a = port to read from ; outputs: z true if no character present ; z false if character returned in a ; clobbers none ; 42 cycles including return when no character present ;----------------------------------------------------------------------------- serIn ora a ;(4) port 0 or 1? jnz s2InB ;(10) port 1, 2nd serial port ; Input from console serial port s2InA in SIOACR ;(10+1) see if a new character is present ani SIORDA ;(7) rz ;(10) no character, return zero status in SIOADR ;return character and non-zero status ret ; Input from 2nd serial port s2InB in SIOBCR ;(10+1) see if a new character is present ani SIORDA ;(7) rz ;(10) no character, return zero status in SIOBDR ;return character and non-zero status ret ;----------------------------------------------------------------------------- ; Hardware specific I/O ; serOut - output character to port specified in a ; 0 = console serial port ; 1 = second serial port ; inputs: a = port to transmit through ; b = character to send ; clobbers a ;----------------------------------------------------------------------------- serOut ora a ;port 0 or 1 ? jnz s2OutB ;second serial port ; Send character through console serial port S2OutA in SIOACR ;wait for OK to transmit ani SIOTRE jz S2OutA mov a,b ;a=character to transmit out SIOADR ;send it ret ; Send character through second serial port s2OutB in SIOBCR ;wait for OK to transmit ani SIOTRE jz s2OutB mov a,b ;a=character to transmit out SIOBDR ;send it ret ;**************************************************************************** ; ; Northstar disk I/O routines, mostly written by M Eberhard. ; ; Commands are issued to the N* controller by *reading* memory ; locations. Data and Control bits to the controller are embedded ; in the read addresses. What you get back depends on what you ; read - either one of 2 status bytes, or disk data. The commands ; constructed below take care of this. ; ; 2 RAM locations are needed: ; curTrk is used to remember the current track ; and should be initialized to 0FFh ; drvNum remembers the current unit. On the N* controller, ; disks are 1 to 3. 0 means none selected. ;************************************************ ; Northstar disk Controller Addresses & Commands ; (Read or write from address to execute command) ;************************************************ NSCTRL equ 0E800h ;Northstar disk controller NSBOOT equ NSCTRL+100h ;disk boot PROM entry point NWRITE equ NSCTRL+200h ;write prefix (data in low byte) NCOMND equ NSCTRL+300h ;commands base address NASTAT equ NCOMND+10h ;read A status NBSTAT equ NCOMND+30h ;read B status NSTRST equ NCOMND+09h ;set track step flip flop NCTRST equ NCOMND+08h ;clear track step flip flop NSTOUT equ NCOMND+1Ch ;set step direction to 'out' NSTIN equ NCOMND+1Dh ;set step direction to 'in' NMOTRA equ NCOMND+90h ;motor on, read A status NRBYTE equ NCOMND+50h ;read a byte of disk data NWRCRD equ NCOMND+04h ;start write-sector sequence NRSEFL equ NCOMND+94h ;reset sector flag, restart motor timeout ;**************************** ; Disk Controller Status Bits ;**************************** NSTR0 equ 1 ;NASTAT: track 0 NSWP equ 2 ;NASTAT: write protect NSBDY equ 4 ;NASTAT: body (sync chr found) NSWRT equ 8 ;NASTAT: write ready NSMO equ 10h ;NASTAT & NBSTAT: motor on NSWN equ 40h ;NASTAT & NBSTAT: window flag NSSF equ 80h ;NASTAT & NBSTAT: sector flag NSSP equ 0Fh ;NBSTAT: sector position ;************************** ; Disk Controller constants ;************************** SYNC equ 0FBh ;header sync charactor WRMUP equ 32h ;warm up time in sectors SETL equ 0Dh ;head settling time in sectors SWAIT equ 08Ch ;max wait for body before error MAXUNT equ 3 ;max disk drive unit (0 not allowed) MAXTRK equ 39 ;max track MAXSEC equ 9 ;max sector (SA400 and SA400L) ;************************** ;Disk Subsystem Subroutines ;************************** ;***Subroutine************************************** ; dRead - Read sector on current track. ; On Entry: ; Drive is selected, motor is running and sector ; sync was just previously detected ; hl->sector buffer ; On Exit: ; clobbers b,c,h,l ;*************************************************** ;Wait for sector body dRead: mvi b,SWAIT ;max time until body NSRD1: dcr b jz NOSYNC ;NO sync character lda NASTAT ;LOOK for sync chr ani NSBDY jz NSRD1 ;keep looking lxi b,0 ;initial CRC ;read sector data NSRD2: lda NRBYTE ;read a byte mov m,a ;save it xra b ;compute checksum rlc mov b,a inx h ;bump pointers dcr c ;256 byteS jnz NSRD2 ;check CRC lda NRBYTE ;get disk CRC xra b ;compare to computed CRC ret ;Z flag set if OK, else error NOSYNC: dcr b ;b=0ffh ret ;return with zero false ;***Subroutine************************************** ; dVerify - Verify sector on current track ; On Entry: ; Drive is selected, motor is running and sector ; sync was just previously detected ; hl->buffer to compare against ; On Exit: ; clobbers b,c,h,l ;*************************************************** ;Wait for sector body dVerify: mvi b,SWAIT ;max time until body NSVF1: dcr b jz NOSYNC ;NO sync character lda NASTAT ;LOOK for sync chr ani NSBDY jz NSVF1 ;keep looking lxi b,0 ;initial CRC ;read and verify sector data NSVF2: lda NRBYTE ;read a byte cmp m ;compare to validate data rnz ;match fail xra b ;compute checksum rlc mov b,a inx h ;bump pointer dcr c ;256 byteS jnz NSVF2 ;check CRC lda NRBYTE ;get disk CRC xra b ;compare to computed CRC ret ;Z flag set if OK, else error if 0 ;write not used ;***Subroutine************************************** ; dWrite - Write a sector on current track ; On Entry: ; Drive is selected, motor is running and sector ; sync was just previously detected ; hl->buffer address ; On Exit: ; clobbers b,c,h,l ;*************************************************** dWrite: push d ;save de lda NWRCRD ;prepare to write NSWR1: lda NASTAT ;wait for controller ani NSWRT ;..to get ready to write. jz NSWR1 ;write sector header lxi b,NWRITE ;C=0,b=write prefix lxi d,000FH ;number of header zeros, ;init CRC calculation NSWR2: ldax b ;write now push psw ;waste 21 cycles, need >8us between pop psw ;two ldax b's even at 4mhz dcr e ;count header zeros jnz NSWR2 ;write sector sync character mvi c,SYNC ;write sync chr ldax b nop ;ensure >8us at 4mhz to next ldax b nop ;write sector data NSWR3: mov c,m ;get chr from RAM mov a,c ;Calculate CRC xra d ;keep it in d rlc mov d,a ldax b ;write chr to disk inx h ;bump pointers dcr e ;write 256 bytes jnz NSWR3 ;write sector CRC mov c,d ;Write CRC nop ;ensure >8us at 4mz between ldax b nop ldax b pop d ;restore de ret ;don't wait for end of sector ;***Subroutine************************************** ; dChkWP - check if disk is write protected. ; On Entry: ; disk already selected ; On Exit: ; returns if disk is not protected. Otherwise, an error ; message is displayed and the program started over. ; clobbers h,l ;*************************************************** dChkWP lda NASTAT ;check for write protect ani NSWP rz ;return if not protected ; Disk write protected. Display error and restart program. lxi h,mWrtPrt ;otherwise, display error message call dispMsg ;display the error lxi sp,ourStk ;re-init stack point jmp getDrv endif ;***Subroutine************************************** ; dSeek - Seek Track. The motor timeout is restarted ; as a result of this call. ; On Entry: ; curTrk = current track, FFh means we don't know ; l = desired track ; On Exit: ; curTrk = current track ; trashes all registers ;*************************************************** dSeek: call NSELCT ;select drive, spin up lda curTrk ;where are we? cpi 0FFh cz dRestor ;lost: restore ;compute the required number of steps and the direction sub l ;which way to step? rz ;already there? lxi d,NSTOUT ;desiredcurrent NSSK1: ;remember target track, and step there mov h,a ;number of steps mov a,l ;remember target track sta curTrk ;..is new track, when done jmp NSSTEP ;go step h tracks ;***Subroutine************************* ; dRestor - Restore to track 0 ; On Exit: ; Z set and curTrk=0 if track 0 found ; trashes psw,bc,h ;************************************** dRestor: call NSELCT ;select drive, spin up ;step in once, in case the head is lost lxi d,NSTIN ;step in once mvi h,1 call NSSTEP ;step in now jz STUCK0 ;z: Stuck on track 0 ;step out enough times that we should find track 0 even ;if the SA400's actuator is out of its spiral groove mvi h,MAXTRK+16 ;more than enough lxi d,NSTOUT ;prepare to step out call NSSTEP ;steppin' out to track 0 rz ;z set: found track 0 ;Error: track 0 not detected despite many steps outward lxi h,mNoTrk0 call dispMsg lxi sp,ourStk ;initialize stack pointer jmp getDrv ;start over asking for drive num ;Error: stuck on track zero STUCK0: lxi h,mStkTk0 ;stuck on track zero message call dispMsg lxi sp,ourStk ;initialize stack pointer jmp getDrv ;start over asking for drive num ;***Subroutine************************* ; Step head ; On Entry: ; h = number of steps, >0 ; de = step command - NSTIN or NSTOUT ; On Exit: ; Z set and curTrk=0 if track 0 found ; trashes psw,bc,h ;************************************** NSSTEP: ldax d ;set step direction NSSTP1: lda NSTRST ;Reset step flipflop xthl ;must be here for delay. xthl ;at least 10 uSec mvi b,2 ;step timer lda NCTRST ;set step flipflop call NSWAIT ;wait 2 sector times lda NASTAT ;at track 0? ani NSTR0 jnz NSSTP2 ;y: stop stepping dcr h ;n: step again jnz NSSTP1 ;stepped enough? inr a ;clear Z: not track 0 ret ;on track 0. clear curTrk, and return with Z set NSSTP2: xra a ;set Z: track 0 sta curTrk ret ;***Subroutine******************************** ; NSELCT - Select drive. Turn on the motor if necessary, ; wait for head settle time. ; On Entry: ; drvNum = desired drive (1-3) ; trashes psw,bc ;********************************************* NSELCT: mvi b,WRMUP-SETL ;warmup motor time ;long delay if motors are off lda NMOTRA ;turn on drive motors ani NSMO ;already on? cz NSWAIT ;n: spin up ;select drive, load head mvi b,NCOMND/256 ;select drive lda drvNum mov c,a ldax b ;Load head on drive c ;wait for settling time after head load mvi b,SETL ;head settling time ;fall into NSWAIT to stall ;***Subroutine*********************** ; Wait for b sectors ; On Entry: ; b = number of sectors to wait for ; trashes psw,b ;************************************ NSWAIT: lda NRSEFL ;reset sector flag, restart motor timeout NSWAT1: lda NASTAT ;get status a rlc ;test NSSF, sector flag set? jnc NSWAT1 ;no dcr b ;wait for b sectors to pass rz jmp NSWAIT ;***Subroutine****************************** ; dWtSec - Wait for specified sector. ; On Entry: ; Drive is selected, motor is running ; e = desired sector number ; On Exit: ; drive is at proper sector ; e = sector number ; bc = byte offset of this sector in a track ;******************************************* dWtSec: lda NRSEFL ;reset sector flag, restart motor timeout NSWTS1: lda NBSTAT ;a=sector flag and sector number rlc ;test NSSF, sector flag set? jnc NSWTS1 ; Sector flag set, get sector number alone and see if this ; is the right sector lda NBSTAT ;get sector again to be safe ani NSSP ;get sector bits alone cmp e ;the sector we want? jnz dWtSec ;no, keep looking ; Compute the offset of this sector within the track and return in bc mov b,a ;256 bytes per sector mvi c,0 ret ;***Subroutine****************************** ; dNxtSec - Wait for next (any) sector ; On Entry: ; Drive is selected, motor is running ; On Exit: ; drive is at proper sector ; e = sector number ; bc = byte offset of this sector in a track ;******************************************* dNxtSec: lda NRSEFL ;reset sector flag, restart motor timeout NSWTS2: lda NBSTAT ;a=sector flag and sector number rlc ;test NSSF, sector flag set? jnc NSWTS2 ; Sector flag set, return the sector number in e and compute the offset ; of this sector within the track. lda NBSTAT ;get sector again to be safe ani NSSP ;get sector bits alone mov e,a ;return sector in e mov b,a ;256 bytes per sector mvi c,0 ret ;************************************************************************** ; ; Data area ; ;************************************************************************** ; disk variables drvNum ds 1 ;drive number to use curTrk ds 1 ;current track number drive is on trkNum ds 1 ;track number to read trkPtr ds 2 ;pointer into trkBuf at track boundaries bufEnd ds 2 ;end address + 1 of last track spot in RAM ; retry logic variables dskRtry ds 1 ;disk read retry counter rtStep ds 1 ;current retry step trkErr ds 1 ;non zero if error occured on track ; xmodem variables xfrPort ds 1 ;pseudo port for file transfer xmRetry ds 1 ;xmodem retry counter blkNum ds 1 ;current xmodem block number crcFlag ds 1 ;non zero if using CRC instead of checksum crc16 ds 2 ;crc-16 result sndPtr ds 2 ;pointer for start of XMODEM send ; misc variables cpmFlag ds 1 ;non-zero if running under CP/M baseDrv ds 1 ;ascii 1st drive - baseDrv = 0 ds 64 ;stack space ourStk equ $ ; track buffer runs from here to the end of memory ds PKTLEN ;space for pre-pended unsent data trkBuf equ $ end