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Assembly Source File | 1984-04-29 | 20.7 KB | 828 lines

TITLE 'SDNBIOS - N* SD CP/M 2.2 BIOS OF 06/19/81' ; ; THIS BIOS CONTAINS ROUTINES TO SUPPORT THE ; FOLLOWING HARDWARE: ; ; DISK: NORTH STAR MDC-A4 SINGLE DENSITY 5.25" ; FLOPPY DISK UNITS 1 AND 2 AS CP/M DRIVES ; A: AND B: ; ; CONSOLE AND LIST ROUTINES ARE LOCATED IN A ; SEPARATE MODULE LOADED BY THE BOOTSTRAP ROUTINE ; INTO HIGH MEMORY AT ADDRESS USER. THAT VALUE IS ; ASSUMED TO BE ON A 1K BOUNDARY, AND THE USER ; ROUTINES ARE RESTRICTED TO 2 PAGES (SEE BOOTSTRAP ; INFO BELOW), WITH 2 PAGES OF SCRATCH ABOVE AVAILABLE ; FOR USE. THIS BIOS USES THE 1ST OF THOSE SCRATCH ; PAGES FOR BDOS BUFFERS AND ITS OWN VARIABLES. ; ; SINCE THIS BIOS IS SO LARGE, MOVCPM SHOULD BE ; RUN FOR TWO LESS THAN THE DESIRED SYSTEM SIZE ; IN K, I.E. SPECIFY 18 FOR A 20K SYSTEM. ; ; *** IMPORTANT BOOTSTRAP INFORMATION *** ; ; OUR WARM BOOT EXPECTS CCP TO RESIDE ON TRACK ; 1, SECTORS 0-7 INCLUSIVE. BDOS MUST BE ON TRACK ; 1, SECTORS 8-9, THEN CONTINUE ON TRACK 2, SECTORS ; 0-9, THEN FINISH ON TRACK 0, SECTORS 1 AND 9. ; ; THE BOOTSTRAP BLOCK IS LOADED BY THE CONTROLLER ; PROM ROUTINES FROM TRACK 0, SECTOR 4 INTO MEMORY ; AT 2000H. THE BOOTSTRAP ROUTINE WILL THEN LOOK ; FOR THIS BIOS ON TRACK 0, SECTORS 5-8. THE USER ; ROUTINES FOR CONSOLE AND LIST ARE STORED ON TRACK ; 0, SECTORS 2-3. TRACK 0, SECTOR 0 IS RESERVED FOR ; LIFEBOAT-COMPATIBLE ID AND FUTURE EXPANSION. ; ; DISK OPERATING SYSTEM ADDRESSES ; NKSYS EQU 20 ;SYS SIZE IN K BYTES KBYTE EQU 1024 ;1K BYTE SIZE CPMSZ EQU NKSYS*KBYTE ;TOP SYSTEM ADDRESS CPMBS EQU CPMSZ-(22*KBYTE);CP/M BIAS VALUE CCP EQU CPMBS+3400H ;ADDRESS OF CCP BDOS EQU CPMBS+3C00H ;ADDRESS OF BDOS BIOS EQU CPMBS+4A00H ;ADDRESS OF BIOS BIOSR EQU 1F80H-BIOS+200H ;DDT LOAD OFFSET ; (LEAVES ROOM FOR "USER") USER EQU 0A000H ;NON-CONTIGUOUS 1K HIGH RAM IOBYTE EQU 0003H ;CP/M I/O BYTE ADDRESS TPA EQU 100H ;ADDRESS OF TPA SECSZ EQU 128 ;BYTES PER SECTOR HSTSIZ EQU 256*10 ;BYTES PER N* TRACK NDRVS EQU 2 ;# DRIVES IN SYSTEM ; CR EQU 0DH ;ASCII CARRIAGE RETURN LF EQU 0AH ;ASCII LINE FEED ; ; BDOS CONSTANTS ON ENTRY TO WRITE ; WRALL EQU 0 ;WRITE TO ALLOCATED WRDIR EQU 1 ;WRITE TO DIRECTORY WRUAL EQU 2 ;WRITE TO UNALLOCATED ; ; NORTH STAR MEMORY MAPPED I/O ADDRESSES ; WDATA EQU 0EA00H ;WRITE DATA. DATA IS ; LOW 8 ADRESS BITS. CCMND EQU 0EB00H ;CONTROLLER COMMAND ; ; KEYPAD LIGHTS ; LHEX EQU 0DFH ;LEFT HEX LITES MHEX EQU 0DDH ;MIDDLE HEX LITES RHEX EQU 0DBH ;RIGHT HEX LITES ; ; BIOS JUMP VECTOR TABLE ; ORG BIOS ;START OF BIOS CODE ; JMP COLD ;COLD BOOT FROM ROM JMP WARM ;RELOAD CCP/BDOS JMP USER+3 ;GET CONSOLE STATUS JMP USER+6 ;CONSOLE INPUT JMP USER+9 ;CONSOLE OUTPUT JMP USER+12 ;PRINTER OUTPUT JMP USER+15 ;PUNCH OUTPUT JMP USER+18 ;READER INPUT JMP HOME ;HOME SELECTED DRIVE JMP SELDSK ;SELECT DISK DRIVE JMP SETTRK ;SET TRACK NUMBER JMP SETSEC ;SET SECTOR NUMBER JMP SETDMA ;SET TRANSFER ADDRESS JMP DISKRD ;PERFORM DISK READ JMP DISKWR ;PERFORM DISK WRITE JMP USER+21 ;RETURN LIST STAT JMP SECTRN ;TRANSLATE SECTOR ; MSGOT: EQU USER+24 ;MSG OUT ROUTINE HXBOT: EQU USER+27 ;HEX CONVERSION ROUTINE DISKER: EQU USER+30 ;DISK ERROR REPORTER ; ; SELECT DRIVE ; SELDSK: LXI H,0 ;ERROR RETURN CODE MOV A,C ;PUT DRIVE # IN A CPI NDRVS ;CHECK IF LEGAL DRIVE RNC ;NO CARRY IF ILLEGAL STA SEKDSK ;STORE DRIVE NUMBER MOV L,C ;L = DISK NUMBER MVI H,0 ;ZERO H REG DAD H ; *2 DAD H ; *4 DAD H ; *8 DAD H ; *16 (SIZE OF HEADER) LXI D,D0DPH ;DRIVE 0 DPH DAD D ;HL = DRIVE N DPH RET ;RETURN THAT IN HL ; ; HOME DRIVE ; HOME: MVI C,0 ;SET TRACK TO ZERO TO HOME LDA HSTWRT ;CHECK FOR PENDING WRITE ORA A JNZ SETTRK STA HSTACT ;CLEAR HOST ACTIVE IF NOT ; ; SET TRACK ; SETTRK: MOV A,C ;MOVE TRACK NUMBER STA SEKTRK ; THEN SAVE IT RET ;RETURN TO CALLER ; ; SET SECTOR ; SETSEC: MOV A,C ;MOVE SECTOR NUMBER STA SEKSEC ; THEN SAVE IT RET ;RETURN TO CALLER ; ; SET TRANSFER ADDRESS ; SETDMA: MOV H,B ;MOVE ADDR TO HL MOV L,C SHLD DMAADR ; THEN SAVE IT RET ;RETURN TO CALLER ; ; SECTOR TRANSLATION ; SECTRN: MOV H,B MOV L,C INX H ;JUST ADD ONE TO SECNUM RET ; THEN DONE ; ; DEBLOCKING DISK READ. NOTE THAT ON DEBLOCKING READ ; AND WRITE, THE CALLER SECTOR NUMBERS RANGE FROM 1-XX ; DECIMAL. THIS IS FOR COMPATIBILITY WITH 8" FORMATS ; THAT ARE 1-ORIGIN. WE ADJUST FOR THIS THROUGHOUT THE ; DEBLOCKING ROUTINES BY SUBTRACTING 1 FROM SEKSEC ; BEFORE WE USE IT. ; ; TRACK BUFFERING IS DONE HERE. A HOST BLOCK IS ; CONSIDERED THE ENTIRE HOST TRACK. ; DISKRD: XRA A ;END OF UNALLOC SECTORS STA UNACNT ; AFTER READ INR A STA READOP ;READ OPERATION STA RSFLAG ;MUST READ DATA MVI A,WRUAL STA WRTYPE ;TREAT AS UNALLOC JMP RWOPER ;TO PERFORM THE READ ; ; DEBLOCKING DISK WRITE ; DISKWR: XRA A STA READOP ;NOT A READ OPERATION MOV A,C ;WRITE TYPE IN C STA WRTYPE CPI WRUAL ;WRITE UNALLOCATED? JNZ CHKUNA ;CHECK FOR UNALLOC ; ; WRITE TO UNALLOCATED, SET PARAMETERS ; LDA BLKMSK ;NEXT UNALLOC RECS INR A STA UNACNT LDA SEKDSK ;DISK TO SEEK STA UNADSK ;UNADSK = SEKDSK LDA SEKTRK STA UNATRK ;UNATRK = SEKTRK LDA SEKSEC STA UNASEC ;UNASEC = SEKSEC ; ; CHECK FOR WRITE TO UNALLOCATED SECTOR ; CHKUNA: LDA UNACNT ;ANY UNALLOC REMAIN? ORA A JZ ALLOC ;SKIP IF NOT ; ; MORE UNALLOCATED RECORDS REMAIN ; DCR A ;UNACNT = UNACNT - 1 STA UNACNT LDA SEKDSK ;SAME DISK? LXI H,UNADSK CMP M ;SEKDSK = UNADSK? JNZ ALLOC ;SKIP IF NOT ; ; DISKS ARE THE SAME, CHECK TRACKS ; LDA SEKTRK LXI H,UNATRK CMP M ;SEKTRK = UNATRK? JNZ ALLOC ;SKIP IF NOT ; ; TRACKS ARE THE SAME, CHECK SECTORS ; LDA SEKSEC LXI H,UNASEC CMP M ;SEKSEC = UNASEC? JNZ ALLOC ;SKIP IF NOT ; ; MATCH, MOVE TO NEXT SECTOR FOR FUTURE REF ; INR M ;UNASEC = UNASEC+1 LDA DPBNSS ;CHECK FOR END OF TRACK CMP M JNC NOOVF ;SKIP IF STILL ON TRACK ; ; OVERFLOW TO NEXT TRACK ; MVI M,1 ;UNASEC = 1 LXI H,UNATRK INR M ;UNATRK = UNATRK+1 ; ; MATCH FOUND, MARK AS UNNECESSARY READ ; NOOVF: XRA A STA RSFLAG ;RSFLAG = 0 JMP RWOPER ;GO DO WRITE ; ; NOT AN UNALLOCATED RECORD, REQUIRES PRE-READ ; ALLOC: XRA A STA UNACNT ;UNACNT = 0 INR A STA RSFLAG ;RSFLAG = 1 ; ; COMMON CODE FOR READ AND WRITE FOLLOWS ; RWOPER: XRA A STA ERFLAG ;NO ERRORS (YET) ; ; ACTIVE HOST TRACK? ; LXI H,HSTACT ;HOST ACTIVE FLAG MOV A,M MVI M,1 ;ALWAYS BECOMES 1 ORA A ;WAS IT ALREADY? JZ FILHST ;FILL HOST IF NOT ; ; HOST BUFFER ACTIVE, SAME AS SEEK BUFFER? ; LDA SEKDSK LXI H,HSTDSK ;SAME DISK? CMP M ;SEKDSK = HSTDSK? JNZ NOMATCH ; ; SAME DISK, CHECK TRACK ; LDA SEKTRK LXI H,HSTTRK CMP M ;SEKTRK = HSTTRK? JZ MATCH ;SKIP IF MATCH ; ; MUST FLUSH HOST BUFFER FOR NEW TRACK ; NOMATCH: LDA HSTWRT ;HOST WRITTEN? ORA A CNZ WRITEHST ;CLEAR HOST BUFFER LDA ERFLAG ;CHECK FOR ERROR ORA A RNZ ;RETURN ERROR IF SO ; FILHST: LDA SEKDSK ;MAY HAVE TO FILL HOST BUFFER STA HSTDSK LDA SEKTRK STA HSTTRK XRA A STA HSTWRT ;NO PENDING WRITE LDA RSFLAG ;NEED TO READ? ORA A JZ MATCH ;NO IF FLAG ZERO CALL READHST ;READ HOST LDA ERFLAG ;CHECK FOR ERRORS ORA A RNZ ;NO MORE IF SO ; ; COPY DATA TO OR FROM BUFFER ; MATCH: LDA SEKSEC ;GET SECTOR NUMBER DCR A ;ADJUST FOR 1-ORIGIN RAR ;GET VALUE SHIFTED MOV H,A ; LEFT 7 IN HL MVI A,0 RAR MOV L,A ; ; HL CONTAINS RELATIVE HOST BUFFER ADDRESS ; LXI D,HSTBUF ;PT TO TRACK BUFFER DAD D ;HL = HOST ADDRESS XCHG ;NOW IN DE LHLD DMAADR ;GET/PUT CP/M DATA MVI C,SECSZ ;LENGTH OF MOVE LDA READOP ;WHICH WAY? ORA A JNZ RWMOVE ;SKIP IF READ ; ; WRITE OPERATION, MARK AND SWITCH DIRECTION ; INR A ;ACC KNOWN ZERO ABOVE STA HSTWRT ;HSTWRT = 1 XCHG ;SOURCE/DEST SWAP ; RWMOVE: LDAX D ;SOURCE CHARACTER INX D MOV M,A ;TO DEST INX H DCR C ;LOOP 128 TIMES JNZ RWMOVE ; ; DATA HAS BEEN MOVED TO/FROM HOST BUFFER ; LDA WRTYPE ;WRITE TYPE CPI WRDIR ;TO DIRECTORY? MVI A,0 ;NO ERROR AT THIS PT RNZ ;RET IF NOT DIR WRITE ; ; CLEAR HOST BUFFER FOR DIRECTORY WRITE ; CALL WRITEHST LDA ERFLAG RET ; ; WRITEHST PERFORMS THE PHYSICAL WRITE TO THE ; NORTH STAR DISK. ON ENTRY, DRIVE IS IN HSTDSK, ; AND TRACK IS IN HSTTRK. ON EXIT, ERROR FLAG ; IS IN ERFLAG (ZERO IF NONE). ; EXIT, ERROR FLAG IS IN ERFLAG (ZERO IF NONE). ; ; IT IS ASSUMED INTERRUPTS ARE DISABLED AT ; THIS POINT. IF NOT, I/O MAY BE DISRUPTED. ; WRITEHST: ;WRITE HOST XRA A ;BUFFER WILL BE CLEARED STA HSTWRT STA ERSEC ;NO SECTOR IN ERROR YET CALL SETUP ;SELECT DRIVE, SEEK, AND ; POSITION TO SECTOR ZERO RNZ ;SECTOR NOT FOUND IS FATAL LHLD HSTADR ;GET ADDRESS TO WRITE FROM MVI A,10 ;INIT # BLKS TO WRITE ; ; HERE TO WRITE NEXT SECTOR. WRITE-PROTECT CHECK IS ; DONE EVERY SECTOR TO HELP KILL TIME. ; WRIT5: PUSH PSW ;SAVE # BLKS LEFT LDA CCMND+10H ;GET A-STATUS ANI 02H ;IS DISK WRITE-PROTECTED? MVI A,6 ;ASSUME SO, ERROR CODE 6 JNZ WPERR ;WRITE ALWAYS FAILS IF SO LDA CCMND+04H ;INITIATE SECTOR WRITE ; WRIT10: LDA CCMND+10H ;GET A-STATUS ANI 08H ;MUST LOOP UNTIL 96 USEC WINDOW JZ WRIT10 ; PAST, SO LOOP UNTIL WRT TRUE ; ; NOW WRITE THE 15 BYTES OF LEADING ZEROES ON THE SECTOR ; LXI B,15 ;GET ZERO IN C-REG, AND ; LOAD CNT IN B-REG ; WRIT15: MOV E,B ;KILL TIME AND GET ZERO IN E-REG MVI D,WDATA SHR 8 ;KILL TIME BY LOADING D FOR LATER LDAX D ;WRITE A ZERO BYTE MOV A,M ;KILL MORE TIME DCR C ;COUNT OFF A ZERO BYTE JNZ WRIT15 ;DO THEM ALL ; ; FOLLOW WITH SYNCH BYTE ; MOV E,A ;KILL TIME MVI E,0FBH ;THIS IS THE SYNCH BYTE VALUE LDAX D ;WRITE OUT SYNCH BYTE MOV A,M ;KILL TIME MOV A,M ; ; NOW WRITE OUT 256 BYTES. B IS ZERO FROM ABOVE TO INIT ; THE CRC BYTE. C IS ZERO FROM COUNTING OUT ABOVE TO INIT ; 256-BYTE COUNTER FOR HERE. ; WRIT20: MOV A,M ;GET NEXT BYTE TO OUTPUT MOV E,A ; IN OUTPUT REG XRA B ;ADD INTO CHECKSUM RLC MOV B,A ;LEAVE CHECKSUM IN B LDAX D ;WRITE DATA BYTE TO DISK INX H ;BOP BUF PTR DCR C ;COUNT OFF LAST BYTE JNZ WRIT20 ;GO BACK IF MORE TO WRITE MOV E,B ;IF NOT, TIME TO WRITE CHECKSUM MOV E,B ;KILL TIME INX B ;KILL MORE TIME LDAX D ; THEN WRITE THE BYTE CALL WAIT1S ;WAIT FOR NEXT SECTOR POP PSW ;GET COUNT OFF STACK DCR A ;COUNT OFF LAST SECTOR JNZ WRIT5 ;GO BACK IF MORE TO WRITE STA ERFLAG ;FLAG NO ERRORS RET ; THEN RETURN TO CALLER ; WPERR: STA ERFLAG ;STORE ERROR CODE POP PSW ;CLEAN OFF STACK LXI H,WPEMSG ;WRITE PROTECT ERROR ; DSKERR: XCHG LHLD HSTDSK ;PICK UP DISK AND TRACK XCHG ;LEAVE IN DE LDA ERSEC ;GET SECTOR IN ERROR JMP DISKER ;GO REPORT ; ; READHST PERFORMS THE PHYSICAL READ FROM THE ; NORTH STAR DISK. ON ENTRY, DRIVE IS IN HSTDSK, ; TRACK IS IN HSTTRK, SECTOR IS IN HSTSEC. ON ; EXIT, ERROR FLAG IS IN ERFLAG (ZERO IF NONE). ; ; *** INTERRUPTS MUST BE DISABLED HERE *** ; READHST: MVI A,10 ;RETRY COUNT ON ERROR STA RTCNT ; READRT: CALL SETUP ;SELECT DRIVE, SEEK, AND ; POSITION TO SECTOR ZERO RNZ ;SECTOR NOT FOUND IS FATAL XRA A STA ERFLAG ;NO ERRORS YET LHLD HSTADR ;READ INTO HERE MVI A,10 ;INIT # BLKS TO READ ; ; HERE TO READ NEXT SECTOR. START BY LOOKING FOR ; SYNCH BYTE. ; RNEXTS: PUSH PSW ;SAVE # BLKS LEFT TO READ MVI B,08CH ;COUNT FOR SYNC CHAR LOOP LXI D,CCMND+50H ;SET UP READ DATA REGS MVI C,0 ;LOAD COUNT OF 256 FOR READ ; ; NOW WAIT FOR SYNC CHAR DETECTED. ERROR IF WE HAVE TO ; WAIT TOO LONG. ; READ5: LDA CCMND+10H ;GET A-STATUS ANI 04H ;SYNCH CHAR DETECTED? JNZ READ15 ;OUT IF GOT IT DCR B ;COUNT DOWN IF NOT JNZ READ5 ;GO BACK IF STILL OK MVI A,1 ;SYNC ERROR IF WAITED TOO LONG LXI H,SYEMSG ;SYNC ERROR MESSAGE ; RERR: STA ERFLAG ;STORE ERROR CODE POP B ;GET BLK CNT IN B MVI A,10 SUB B ;CALC SECTOR # IN ERROR STA ERSEC ;SAVE FOR REPORTING LDA RTCNT ;COUNT OFF A RETRY DCR A STA RTCNT JNZ READRT ;IF COUNT LEFT, GO RETRY ; ; READ ERROR RETRIES FAILED. FLAG ERROR. ; FRERR: JMP DSKERR ;TELL OPERATOR OF ERROR THEN OUT ; ; READ THE DATA INTO HSTBUF ; READ15: MOV B,C ;INIT CHECKSUM FROM ZERO IN C ; READ20: LDAX D ;READ NEXT DATA BYTE MOV M,A ; AND PUT IT IN BUFFER XRA B ;ADD TO CHECKSUM RLC MOV B,A INX H ;BOP BUFFER PTR DCR C ;COUNT OFF LAST BYTE JNZ READ20 ;GO BACK IF MORE TO DO LDAX D ; ELSE READ CRC BYTE XRA B ; AND CHECK IT AGAINST OURS JZ READ25 ;GO ON IF READ OK MVI A,2 ;IF NOT, FLAG CHECKSUM ERROR LXI H,RERMSG ;MESSAGE IF NEEDED JMP RERR ;GO MAYBE RETRY ; READ25: CALL WAIT1S ;WAIT FOR NEXT SECTOR POP PSW ;GET # BLKS LEFT DCR A ;COUNT ONE OFF JNZ RNEXTS ;GO BACK IF MORE STA ERFLAG ;IF DONE, FLAG NO ERROR RET ; THEN RETURN TO CALLER ; ; SETUP SELECTS THE UNIT CORRESPONDING TO HSTDSK, ; THEN SEEKS TO THE TRACK SPECIFIED BY HSTTRK. ; ON RETURN, ERFLAG CONTAINS A NON-ZERO VALUE IF ; AN ERROR WAS DETECTED. ONLY UNITS 1 AND 2 ARE ; SUPPORTED TO SAVE CODE. ; SETUP: LDA HSTDSK ;WANT THIS DISK INR A ;REMAP TO CONTROLLER MASK MOV C,A ;SAVE IN REG C LDA CCMND+90H ;KICK MOTORS AND GET A-STATUS ANI 10H ;ARE MOTORS ALREADY ON? JNZ SET5 ;BRANCH IF SO MVI D,50 ;WAIT 1 SECOND FOR MOTORS TO CALL SCWAIT ; COME UP TO SPEED IF NOT JMP SET10 ; THEN GO SELECT DRIVE ; SET5: LDA CURDSK ;IS THIS THE CURRENT DISK? CMP C JZ SET20 ;GO SEEK TO TRACK IF SO ; ; MUST SELECT NEW DISK ; SET10: MOV A,C STA CURDSK ;NEW CURRENT DISK MVI B,CCMND SHR 8 ;SET UP FOR SELECT LDAX B ; AND DO IT MVI D,13 ;WAIT 13 SECTOR TIMES AFTERWARDS CALL SCWAIT ; ; SEEK TO TRACK SPECIFIED BY HSTTRK NOW. ; SET20: LDA HSTDSK ;GET NSTRK INDEX MOV C,A MVI B,0 LXI H,NSTRK ;PT AT TABLE DAD B ; THEN AT CORRECT ENTRY MOV A,M ;GET CURRENT TRACK XRI 59H ;WAS DISK EVER ACCESSED? PUSH H ;SAVE TABLE PTR CZ SEEK ;HOME DISK IF 1ST SEEK POP H ;RESTORE TABLE PTR LDA HSTTRK ;GET DESIRED TRACK # CALL SEEK ;SEEK TO HSTTRK ; ; HERE TO POSITION TO SECTOR ZERO WITHIN THE ; CURRENT TRACK. ERROR IS RETURNED BY NON-ZERO ; IF WE CAN'T FIND THE SECTOR AFTER 30 TRIES. ; MVI B,30 ;LOOK AT THIS MANY SECTORS ; POSEC: CALL WAIT1S ;WAIT FOR NEXT SECTOR LDA CCMND+030H ;GET B-STATUS WITH SECTOR # ANI 0FH ;STRIP NON-SECTOR BITS RZ ;OUT IF GOT SECTOR ZERO DCR B ;COUNT OFF IF DIDN'T JNZ POSEC ;GO BACK IF NOT GIVING UP MVI A,1 STA ERFLAG ;SET ERROR FLAG LXI H,SNFMSG CALL DSKERR ;REPORT ERROR XRA A INR A RET ;RETURN NON-ZERO TO CALLER ; ; SEEK TO TRACK SPECIFIED BY ACC. CURRENT PTR INTO ; NSTRK TABLE IS IN HL. ; SEEK: MVI D,LHEX MOV E,A STAX D ;DISPLAY TARGET TRK # MVI D,MHEX MOV E,M STAX D ;DISPLAY SOURCE TRK # MOV C,A ;SAVE TARGET # IN C SUB M ;SEE HOW FAR AWAY WE ARE ; FROM TARGET TRACK MOV M,C ; BUT ALWAYS SET NEW TRACK MVI D,RHEX MOV E,A STAX D ;DISPLAY DIFF RZ ;IF THERE, DONE LXI H,CCMND+1DH ;ASSUME STEPPING IN MOV C,A ;SAVE STEP COUNT JP STEPIN ;BRANCH IF RIGHT CMA ;IF WRONG, NEGATE COUNT INR A MOV C,A ; THEN SAVE THAT MOV E,A STAX D ;SHOW CORRECTED COUNT LDA CCMND+10H ;GET A-STATUS ANI 01H ;ARE WE ON TRACK ZERO? RNZ ;MUST BE DONE IF SO LXI H,CCMND+1CH ;IF NOT, STEPPING OUT ; STEPIN: MOV A,M ;SET STEP DIRECTION ; STEP: LDA CCMND+09H ;SET STEP FLIP-FLOP XTHL ;DELAY AT LEAST 10 USEC XTHL LDA CCMND+08H ; THEN RESET FLIP-FLOP TO PULSE MVI D,2 ;NOW WAIT TWO SECTOR TIMES CALL SCWAIT ; WHILE HEAD MOVES (40 MSEC) LDA CCMND+10H ;GET A-STATUS ANI 01H ;ARE WE AT TRACK ZERO? JZ STEP5 ;PASS IF NOT MVI C,1 ;LAST STEP IF SO ; STEP5: DCR C ;COUNT OFF LAST TRACK JNZ STEPIN ;GO BACK IF MORE TO DO RET ; ELSE RETURN TO CALLER ; ; SECTOR WAIT. ON ENTRY, # SECTORS TO WAIT IS IN D. ; ON EXIT, D=0 AND ACC=GARBAGE. CALL WAIT1S TO WAIT ; ONE SECTOR TIME. ; WAIT1S: MVI D,1 ;WAIT ONE SECTOR TIME ; SCWAIT: LDA CCMND+14H ;RESET SECTOR FLAG SCW5: LDA CCMND+90H ;GET A-STATUS AND KICK MOTORS ANI 80H ;CHECK SECTOR FLAG JZ SCW5 ;WAIT FOR IT IF NOT UP DCR D ;COUNT DOWN WAIT COUNTER RZ ;RETURN IF DONE COUNTING JMP SCWAIT ; ELSE GO COUNT MORE ; ; BLOCK - BLOCK MOVE (Z80 LDIR REGISTER USAGE) ; BLOCK: MOV A,M ;GET BYTE STAX D ;STORE IT INX H ;BOP PTRS INX D DCX B ;COUNT OFF BYTE MOV A,B ;CHECK FOR DONE ORA C JNZ BLOCK ;GO BACK IF NOT RET ; ; COLD BOOT ENTRY. SET UP FIRST-TIME BIOS STUFF. ; COLD: LXI SP,80H ;SET SP TO SCRATCH AREA LXI H,CCP ;WHERE TO START CP/M PUSH H JMP CPMLD ;GO LOAD CCP/BDOS ; ; WARM BOOT ENTRY. LOAD CCP/BDOS AND INITIALIZE ; WARM: LDA 4 ;GET CURRENT DEFAULT DISK MOV B,A ;SAVE IT ANI 0F0H ;GET USER # MOV C,A ;SAVE THAT MOV A,B ANI 00FH ;ISOLATE DISK # CPI NDRVS ;IS IT LEGAL? JC WRMOK ;GO ON IF SO XRA A ;BACK TO DRIVE ZERO IF NOT MOV C,A ;USER # PROB BAD TOO WRMOK: ORA C ;COMBINE WITH USER # STA DFIMG ;PUT TO BASE PAGE IMAGE LXI SP,80H ;SET SP TO SCRATCH RAM LXI H,CCP+3 ;CP/M WARM START ADDR PUSH H ; ; MERGE HERE FROM COLD BOOT ; CPMLD: LDA IOBYTE ;GET CURRENT IOBYTE STA IOIMG ; INTO BASE PAGE IMAGE LXI B,8 ;MOVE ZERO PAGE STUFF LXI D,0 ; DOWN TO ZERO LXI H,BSIMG CALL BLOCK LXI H,05959H ;FORCE HOME OF DRIVES SHLD NSTRK ; A, B MOV A,H ;MAKE SURE NEW DISK SELECTED STA CURDSK XRA A ;DRIVE ZERO VALUE STA HSTDSK STA HSTACT ;HOST BUFFER INACTIVE STA HSTWRT ;NO HOST WRITE PENDING STA UNACNT ;CLEAR UNALLOC COUNT LXI H,CCP ;CP/M CCP ADDRESS SHLD HSTADR ;READ INTO THERE INR A ;GET 1 IN ACC STA HSTTRK ;READ FROM TRACK ONE CALL WRMRD ; RIGHT INTO MEMORY LXI H,CCP+HSTSIZ ;NEXT CHUNK SHLD HSTADR MVI A,2 ; OFF OF TRACK TWO STA HSTTRK CALL WRMRD ;READ IT LXI H,HSTBUF ;NOW READ AND WRITE SHLD HSTADR ; USING DEBLOCK BUFFER XRA A ;READING TRACK ZERO STA HSTTRK CALL WRMRD ;READ IT LXI H,HSTBUF+256 ;MOVE A SECTOR OF BDOS LXI D,CCP+(HSTSIZ*2); TO HERE LXI B,256 CALL BLOCK LXI H,HSTBUF+(256*9);LAST BDOS SECTOR LXI D,CCP+(HSTSIZ*2)+256 LXI B,256 CALL BLOCK LDA DFIMG ;RETRIEVE LAST USED DRIVE MOV C,A ; FOR BDOS RET ; THEN GO TO CP/M ; WRMRD: CALL READHST ;READ HOST TRACK LDA ERFLAG ;CHECK FOR ERROR ORA A RZ ;RETURN IF NONE LXI H,MSGLE ;GET ERROR MESSAGE CALL MSGOT ;TYPE IT HLT ; THEN GIVE UP ; ; DISK ERROR MESSAGES ; WPEMSG: DB 'Protec','t'+80H RERMSG: DB 'CR','C'+80H SNFMSG: DB 'Secto','r'+80H SYEMSG: DB 'Syn','c'+80H ; MSGLE: DB CR,LF,'Boot er','r'+80H ; ; NORTH STAR SD DISK PARAMETER BLOCK ; DPBNSS: DW 20 ;SECTORS PER TRACK DB 3 ;BLOCK SHIFT FACTOR BLKMSK: DB 07H ;BLOCK MASK DB 0 ;NULL MASK DW 80-1 ;DISK SIZE - 1 DW 63 ;DIRECTORY MAX DB 11000000B ;ALLOC 0 DB 0 ;ALLOC 1 DW 16 ;CHECK SIZE DW 3 ;TRACK OFFSET ; ; DRIVE PARAMETER HEADER AREA ; D0DPH: DW 0 ;SECTOR TRAN TBL (NONE) DW 0 ;SCRATCH DW 0 ;SCRATCH DW 0 ;SCRATCH DW DIRBF ;DIRECTORY BUFFER DW DPBNSS ;DRIVE PARAM BLK DW D0CHK ;DRIVE CHANGE BLK DW D0ALL ;DRIVE ALLOCATION ; D1DPH: DW 0,0,0,0,DIRBF,DPBNSS,D1CHK,D1ALL ; ; ZERO PAGE IMAGE -- BLOCK MOVED TO BASE PAGE ; BSIMG: JMP BIOS+03H ;WARM BOOT VECTOR IOIMG: DS 1 ;IOBYTE SET BY CPMLD DFIMG: DB 0 ;DEFAULT DISK -- ZERO ; AFTER COLD BOOT JMP BDOS+06H ;BDOS CALL VECTOR ; LASTG EQU $-1 ;LAST GENNED-IN BYTE ; ; BDOS DIRECTORY BUFFER ; DIRBF: EQU USER+200H ;ALLOCATED ABOVE USER ROUTINES ; ; SCRATCH RAM FOR BDOS ; D0ALL: EQU DIRBF+SECSZ ;A: ALLOCATION BUF D0CHK: EQU D0ALL+12 ;A: CHECK BUF D1ALL: EQU D0CHK+16 ;B: ALLOCATION BUF D1CHK: EQU D1ALL+12 ;B: CHECK BUF ; ; BIOS VARIABLE STORAGE ; SEKDSK: EQU D1CHK+16 ;DRIVE NUMBER SEKTRK: EQU SEKDSK+1 ;TRACK NUMBER SEKSEC: EQU SEKTRK+1 ;SECTOR NUMBER CURDSK: EQU SEKSEC+1 ;CURRENT ACTIVE DISK, ; GENNED-IN FORCE SELECT ERSEC: EQU CURDSK+1 ;SECTOR IN ERROR HSTADR: EQU ERSEC+1 ;HOST BUFFER ADDRESS, NORMALLY ; PTS TO HSTBUF UNLESS BOOTING ; ; HSTDSK MUST BE IMMEDIATELY FOLLOWED BY HSTTRK ; FOR ERROR REPORTING, SO THEY CAN BE LOADED WITH ; A SINGLE LHLD. ; HSTDSK: EQU HSTADR+2 ;HOST DISK NUMBER HSTTRK: EQU HSTDSK+1 ;HOST TRACK NUMBER HSTACT: EQU HSTTRK+1 ;HOST ACTIVE FLAG HSTWRT: EQU HSTACT+1 ;HOST WRITTEN FLAG ERFLAG: EQU HSTWRT+1 ;ERROR REPORTING RTCNT: EQU ERFLAG+1 ;ERROR RETRY COUNTER RSFLAG: EQU RTCNT+1 ;READ SECTOR FLAG READOP: EQU RSFLAG+1 ;1 IF READ OPERATION WRTYPE: EQU READOP+1 ;WRITE OPERATION TYPE DMAADR: EQU WRTYPE+1 ;LAST DMA ADDRESS ; UNACNT: EQU DMAADR+2 ;UNALLOC REC CNT UNADSK: EQU UNACNT+1 ;LAST UNALLOC DISK UNATRK: EQU UNADSK+1 ;LAST UNALLOC TRACK UNASEC: EQU UNATRK+1 ;LAST UNALLOC SECTOR ; ; NORTH STAR CURRENT TRACK TABLE ; NSTRK: EQU UNASEC+1 ;NO CURRENT TRACK YET NSTRK1: EQU NSTRK+1 ;EACH ENTRY CONTAINS ; THE LAST TRACK POSITION ; FOR THE UNIT (1 OR 2) ; ; NORTH STAR HOST SECTOR BUFFER ; HSTBUF: DS HSTSIZ ;HOST BUFFER ; LAST EQU $-1 ;LAST USED BYTE IN MEM ; END