Page Zero Locations
BIOS Jump Vector Adresses
I/O Status Byte Organization/Meaning
:Page Zero Locations
     Locations (hex)	Meaning/Explanation

     0,1,2		Set to JMP WBOOT in BIOS. e.g., C3 03 E8 - JMP E803
     3			IOBYTE (See Section re: I/O Status Byte)
     4			Current default drive/user (drive 0=A, 15=P, etc.)
			High nibble=user no.  Low nibble=drive no.
			ie, user|drive=0000|0001=user0|drive B
     5,6,7		BDOS entry point. e.g., C3 06 DA - JMP DA06
     08-27		Interrupt locations 1 through 5 not used
      * 20		 * RTOKFG sign-on reentry flag from reentry to PBBS
			   from CP/M. (PBBS, BYE)
      * 21		 * LOGST ASCII logon time 8 bytes (PBBS)
      * 2C		 * USREC User record No. 2 bytes (PBBS)
     30-37		Interrupt location 6, not currently used. Reserved
     38-3A		Restart7; contians a jump instruction into DDT or SID
			program when running in debug mode for programmed break
			points, but is not otherwise used by CP/M.
~
     Locations (hex)	Meaning/Explanation

     3B-3F		Not currently used. Reserved.
      * 3B		 * KILBEL  Bell Toggle (BYE, CHAT, PBBS)
      * 3C		 * MSPEED (BYE, KMD, PBBS)
      * 3D		 * Maximum Drive Number (ZCMD, BYE, PBBS, KMD)
      * 3E		 * Wheel Byte (ZCMD, BYE, PBBS, KMD) 0=Remote User
      * 3F		 * Maximum User Number (ZCMD, BYE, PBBS, KMD)
     40-4F		A 16 byte area reserved for scratch by CBIOS, but is
			not used for any other purpose by CP/M.
      * 40		 * Fraction of a second 1/62th
      * 41		 * Seconds
      * 42		 * Minutes
      * 43		 * Hours
      * 44		 * Month
      * 45		 * Day
      * 46		 * Year
      * 4E		 * Mode byte for floppy disk
~
     Locations (hex)	Meaning/Explanation

     50-5B		Not currently used. Reserved
      * 54		 * Count of uploads (KMD, PBBS)
      * 55		 * Count of downloads (KMD, PBBS)
     5C-7C		Default file control block produced for a transient
			program by the Console Command Processor.
     7D-7F		Optional default random record position
     80-FF		Default 128-byte disk buffer which is also filled with
			the command line when a transient is loaded under CCP.
:BIOS Jump Vector Addresses
     Th� followin� i� � tabl� representin� th� entr� point� int� th� CP/� �
BIOS of the major routines accessable to the user:

     Routine   Actual Address      Comment

     BOOT         E800H            Cold Start (Start of CBIOS)
     WBOOT        E803H            Warm Start (WBOOTE)
     CONST        E806H            Console Status
                                    Reg A = 00 if no char ready
                                    Reg A = FF if char ready
     CONIN        E809H            Console char in (Reg A)
     CONOUT       E80CH            Console char out (Reg C)
     LIST         E80FH            List out (Reg C)
     PUNCH        E812H            Punch out (Reg C)
     READER       E815H            Reader in (Reg A)
~
     Routine   Actual Address      Comment

     HOME         E818H            Move to track 00
     SELDSK       E81BH            Select disk given by Reg C (A=0,B=1,...)
     SETTRˠ      E81EȠ           Se�� trac� addres� give� b�� Re� � 
                                      (0...76)
     SETSEà      E821Ƞ           Se�� secto� addres� give� b�� Re� � 
                                      (1...26)
     SETDMA       E824H            Set subsequent DMA address (RP B&C)
     READ         E827H            Read track/sector (block)
     WRITE        E82AH            Write track/sector (block)
     LISTST       E82DH            List Device Status
                                    Reg A = 00 if no char ready
                                    Reg A = FF if char ready
     SECTRAΠ     E830�            Translat�  secto� numbe� i� Re� à usin� �
                                    tabl� pointe� t� b� DE� physica� secto� �
                                    number returned in Reg L
:I/O Status Byte Organization/Meaning
	       Most Significant           Least Significant
     Bits      Bits 6,7    Bits 4,5    Bits 2,3    Bits 0,1
     Device    LIST        PUNCH       READER      CONSOLE

     Value
       00      TTY:        TTY:        TTY:        TTY:
       01      CRT:        PTP:        PTR:        CRT:
       10      LPT:        UP1:        UR1:        BAT:
       11      UL1:        UP2:        UR2:        UC1:

BAT = batch mode.  use the READER as the CONSOLE input, and the LIST
      device as the CONSOLE output
CRT = Console CRT device
LPT = List is the printer device
PTP = Punch is a high speed punch device
PTR = Reader is the high speed reader device
TTY = Printer teletype device
UC1 = User defined console device
UL1 = User defined list device
UPn = User definced punch
URn = User defined reader

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