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- The following has been taken direct from the ZPM3 source and is
- provided as a reference. No guarantees are made with regard to
- its accuracy. The only SCB entries that you should manipulate in
- CP/M 3.0 are the ones published by its authors.
-
-
- ;-------------------------------------------------------------------------------
- ;68 TRAPS FOR WARM BOOT and CONSOLE FUNCTIONS
- ;-------------------------------------------------------------------------------
- ; This table allows you to replace certain BIOS functions with new ones in the
- ; TPA. Because of the banked nature of CP/M 3, simply changing the BIOS
- ; vector could cause a problem as some BIOS functions need to be in the
- ; system bank. If you redirect any of these functions, you should replace
- ; the first jump (0c3h) in each group with a LD HL, (21h). When restoring
- ; the jumps check first that the BIOS vectors you are restoring are in
- ; fact to the BIOS and not to another redirection. To do this, make sure
- ; that the BIOS jumps are pointing above themselves, not down into TPA.
-
- ; For ZPM, the need for the traps has been eliminated.
- ; Because pre-ZPM programs may attempt to write to the first byte of each
- ; trap, these bytes can only be used for other things with some caution!
-
- ; Warm boot trap
- jp ?wboot ;68
- jp dotpa ;6b
- ; Console status trap
- jp ?const ;6e
- jp dotpa ;71
- ; Console input trap
- jp ?conin ;74
- jp dotpa ;77
- ; Console output trap
- jp ?conout ;7a
- jp dotpa ;7d
-
- ;;; List output trap
- ;; jp ?list ;80
- ;; jp dotpa ;83
-
-
- db 0c3h ;80 This first byte should not be used as it
- ; could get changed by programs which attempt to
- ; redirect the printer
-
- db 0 ;81 Not used yet
-
- db 0 ;82 Function 59 load user number. Normally
- ; function 59 loads from the current user
- ; however by setting this byte to a user
- ; number + 1, function 59 will load from
- ; that user area instead (only works with
- ; the ZCCP loader RSX). 0=current user number.
-
- dw 0 ; -19 83
- ; This word is set to the address of the
- ; ZCPR system environment. If it is 0000h
- ; the BDOS assumes that the normal CP/M 3
- ; CCP system is running. Otherwise, the BDOS
- ; will perform certain functions differently.
- ; For example function 152 will use named
- ; directories if available, function 10
- ; will the use message buffers for CCP running
- ; flag and wheel protection of files is enabled.
-
- ; Note that Z3PLUS users can set this word
- ; once Z3PLUS is installed to enable the
- ; extra functions. ZCCP users need not worry
- ; as it will be done automatically.
-
- db 0 ; -17 85
- ; This byte holds control flags for various ZPM3
- ; functions.
- ; bit 7: Setting this bit will clear the function
- ; 10 history buffer. Write only.
- ; bit 6: Controls enabling of the function 10 AUTO
- ; COMMAND facility. If set, control-Q toggles
- ; the facility on and off. If clear, control-Q
- ; has no effect. Read/Write.
- ; bit 5: After function 152 has been called, if a DU:
- ; D:,U: or DIR: spec has been found, this
- ; bit is set and the drive and user is
- ; set in the FCB.
- ; bit 4: This flag is for system use only. It is
- ; set after a function 55 call, but is reset
- ; after any other call.
- ; bit 3: After function 152 has been called, if a
- ; DIR: spec has been parsed, this bit is set
- ; and the user and drive is set in the FCB.
- ; bits 2-0: Not used yet
- ;-------------------------------------------------------------------------------
- ; SYSTEM CONTROL BLOCK (unofficial)
- ;-------------------------------------------------------------------------------
- ; None of these is accessed by the resident BDOS or the user
- dw 0 ; -16 86
- dw 0 ; -14 88
- dw 0 ; -12 8a
- dw 0 ; -10 8c
- dw 0 ; -e 8e
-
- dw 0 ; Bit mapped vector of drives -c 90
- ; with open files since last warm boot.
- dw 0 ; Bit mapped vector of drives -a 92
- ; accessed since last warm boot.
-
- dw 0 ; -8 94
- dw 07h ; -6 96
- dw base+6 ; This word is the address -4 98
- ; of the entry to the BDOS.
- ; It can be used to find the
- ; actual BDOS as opposed to
- ; the top of TPA.
- db 0 ; -2 9a
- db 0 ; -1 9b
- ;------------------------------------------------------------------------------
- ;9c SYSTEM CONTROL BLOCK
- ;------------------------------------------------------------------------------
- ; The official system control block starts here. In reality, the control block
- ; begins before this point, but this is the data section that we are
- ; told about in the DRI literature
- ; In this section, a code is used to signify which sections of the code
- ; access the bytes: a * means that that user may read and write the bytes
- ; a + means that the resident portion of the BDOS accesses the bytes
- ; a ~ means the banked portion of the BDOS accesses the bytes
- ; a ~~ means the banked portion of ZPM3 accesses the bytes, but CPM doesn't
- scb:
- db 0 ;+ Reserved 0 9c
- dw 0 ;+ Reserved 1 9d
- db 0 ; Reserved 3 9f
- db 0 ; Reserved 4 a0
-
- db 31h ; BDOS version number (in BCD) 5 a1
-
- ; The following four bytes may be used for any purpose.
- ; Note that CCP104 used 8 and 9. ZCCP and ZPM3 do not
- ; affect these bytes at all.
- db 0 ;* Reserved for user 6 a2
- db 0 ;* Reserved for user 7 a3
- db 0 ;* Reserved for user 8 a4
- db 0 ;* Reserved for user 9 a5
-
- db 0 ; Reserved 0a a6
- db 0 ; Reserved 0b a7
- db 0 ; Reserved 0c a8
- db 0 ; Reserved 0d a9
- db 0 ; Reserved 0e aa
- db 0 ; Reserved 0f ab
-
- dw 0 ;* Program Error Return Code. 10 ac
- ; This 2-byte field can be used by a program to pass
- ; an error code or value to chained programs. CP/M 3's
- ; conditional command facility also uses this field to
- ; determine if a program executes successfuly. The
- ; BDOS Function 108 (Get/SET Program Return Code) is
- ; used to get/set this value
-
- ; Following byte holds the base page of the top
- ; multiple command RSX (only used by CCP).
- db 0 ; Reserved 12 ae
-
- ; The following bytes are the default disk and user
- ; of the CCP. When the CCP is run, the disk and user
- ; is restored to these values unless flagged not to
- ; by the chain command.
- db 0 ; CCP disk 13 af
- db 0 ; CCP user number 14 b0
-
- ; The following word holds the address of the next
- ; command to get if running multiple commands or
- ; shells. It should not be set by the user.
-
- dw 0 ; Multiple command pointer. CCP 15 b1
-
- db 0 ; System flag CCP use 17 b3
- ; This byte is bit mapped as follows:
- ; Bit 0 Submit flag (set if a file beginning with '$'
- ; is found, cleared by CCP)
- ; 1 RSX flag (set by loader when it loads a null
- ; file with RSXs attached (indicates to CCP
- ; not to attempt to remove the RSXs until the
- ; second warm boot). May be set by RSXs
- ; 2-5 unknown (probably used by utilities)
- ; 6 Change default DU to last program's DU
- ; when chaining.
- ; 7 Chain flag. Set to indicate to CCP that
- ; there is a command to chain to at 080h.
-
- db 0 ; System flag CCP use 18 b4
- ; This byte is bit mapped as follows:
- ; Bit 0 Display command flag
- ; 1 Display command flag
- ; 2 Unknown
- ; 3 File type search order
- ; 4 File type search order
- ; 5 Reset disk system
- ; 6 "GET" RSX flag (set if GET RSX is redirecting)
- ; 7 CCP running flag
- ; Bit 7 is the only one used by the BDOS (in function 10)
-
- db 0 ; System flag CCP use 19 b5
- ; This byte is bit mapped as follows:
- ; Bit 0 Unknown
- ; 1 Cold boot flag
- ; 2-7 Unknown
-
- db 0 ;* Console Width 1a b6
- ; This byte contains the number of columns
- ; (characters) per line on your console relative
- ; to zero. Most systems default this value to
- ; 79. You can set this default value by using
- ; GENCPM or the DEVICE utility. The console width
- ; value is used by CP/M 3 in BDOS function 10. It
- ; is not used by ZPM3. Typing a character into the
- ; last position of the screen, as specified by the
- ; Console Width field, must not cause the terminal
- ; to advance to the next line.
-
- db 0 ; Console Column Position 1b b7
- ; This byte contains the current console column postion
-
- db 0 ;* Console Page Length 1c b8
- ; This byte contains the number of lines (rows) on your
- ; console relative to zero. Most systems default this
- ; value to 23. This default value may be changed by
- ; using GENCPM or the DEVICE utility.
-
- db 0 ; Reserved 1d b9
- ; The following word is used by function 10 and points
- ; to the next character to get in an initialised
- ; function 10 buffer. If a ^C termination occurs or
- ; if a null terminator is found before a CR or LF,
- ; this word is set 0. By setting DE NZ and pointing
- ; this word to a buffer before calling it, you
- ; can have it initialize buffers other than
- ; the default DMA.
-
- dw 0 ;+~Reserved 1e ba
- ; The following word is used by multiple commands and
- ; shells. When function 10 retrieves information from
- ; an initialised buffer, it stores the next character
- ; position at offset 1e and here at 20. If a ^C
- ; termination occurs, 1e is set to 00, but 20 is left
- ; as it was so that the next command can be retrieved.
- ; Therefore, if 1e is 00 and 20 is NZ it means that
- ; a ^C termination happened
-
- dw 0 ;~ Reserved 20 bc
-
-
- ; Redirection flags (following) for each of the five
- ; logical character devices. If your system's BIOS
- ; supports assignment of logical devices to physical
- ; devices, you can direct each of the five logical
- ; character devices to any combination of up to 12
- ; physical devices. The 16 bit word for each device
- ; represents the following:
- ;
- ; Each bit represents a physical device where bit 15
- ; corresponds to device zero and bit 4 corresponds to
- ; device 11. Bits zero through 3 are reserved for
- ; system use and are used for redirection to disk files.
- ;
- dw 0 ;* CONIN Redirection Flag 22 be
- dw 0 ;* CONOUT Redirection Flag 24 c0
- dw 0 ;* AUXIN Redirection Flag 26 c2
- dw 0 ;* AUXOUT Redirection Flag 28 c4
- dw 0 ;* LIST Redirection Flag 2a c6
-
- db 0 ;* Page Mode 2c c8
- ; If this byte is set to zero, some CP/M 3 utilities
- ; and CCP built in commands display one page of data
- ; at a time; you display the next page by pressing
- ; any key. If this byte is not set to zero, the system
- ; displays data on the screen without stopping. To
- ; stop and start the display, you can press CTRL-S and
- ; CTRL-Q respectively.
-
- db 0 ; Default page mode 2d c9
-
- db 0 ;* ~~ 2e ca
- ; Determines if CTRL-H is interpreted as a rub/del
- ; character. If this byte is set to 0, then CTRL-H is
- ; a backspace character (moves back and deletes). If
- ; this byte is set to 0ffh, then CTRL-H is a rub/del
- ; character, echoes the deleted character.
- ; Under ZPM3, the byte has no effect. It should not
- ; be used however as it may be written to by
- ; applications.
-
- db 0 ;* 2f cb
- ; Determines if rub/del is interpreted as CTRL-H
- ; character. If this byte is set to 0, then rub/del
- ; echoes the deleted character. If this byte is
- ; set to 0ffh, then rub/del is interpreted as a
- ; CTRL-H character (moves back and deletes).
- ; Under ZPM3, the byte has no effect. It should not
- ; be used however as it may be written to by
- ; applications.
-
- db 0 ;~ Reserved 30 cc
-
- ; Following two bytes are probably used by CP/M3 utilities
- db 0 ; Reserved 31 cd
- db 0 ; Reserved 32 ce
-
- dw 0 ;*+ Console Mode 33 cf
- ; This is a 16 bit system parameter that determines
- ; the action of certain BDOS Console I/O functions.
-
- dw bnkbuf ; Address of 128 byte buffer 35 d1
-
- db '$' ;*+ Output delimiter character. 37 d3
- ; The default output delimiter character is $, but
- ; you can change this value by using the BDOS Function
- ; 110 Get/Set Output Delimiter.
-
- db 0 ;* List Output Flag 38 d4
- ; If this byte is reset to 0, console output is not
- ; echoed to the list device. If this byte is set
- ; to 1, console output is echoed to the list device.
-
- db 0 ; Scroll flag 39 d5
- ; Following bits set when in system bank and:
- ; Bit 7 is set when function 11 is checking the status.
- ; Bit 6 is set when function 2 is checking input.
- ; Note that raw input (function 6 and function 2 raw)
- ; will not set these bits.
-
- dw scb ; Holds the address of the SCB 3a d6
-
- dw 0080h ;+ Current DMA Address. 3c d8
- ; This address can be set by BDOS Function 26. The
- ; CCP initializes this value to 0080h. BDOS Function
- ; 13, Reset Disk System also sets the DMA address to
- ; 0080h.
-
- db 0 ; Current Disk. 3e da
- ; This byte contains the currently selected default
- ; disk number. This value ranges from 0-15
- ; corresponding to drives a-p, respectively. BDOS
- ; Function 24, Return Current Disk, can be used to
- ; determine the current disk value.
-
- dw 0 ; BDOS variable 'INFO' 3f db
- ; This word is used by the banked portion of the
- ; BDOS. It is normally an entry parameter.
-
- db 0 ; FCB flag 41 dd
- ; If this byte = 0ffh, the word at 03fh is a valid
- ; FCB address.
-
- db 0 ; Same drive flag 42 de
-
- db 0 ;+ BDOS function for error 43 df
-
- db 0 ; Current User Number. 44 e0
- ; This byte contains the current user number. This
- ; value ranges from 0-15. BDOS Function 32,
- ; Get/Set User Code can change or interrogate
- ; the currently active user number. Under ZPM3 you may
- ; change the currently active user number directly
- ; by writing to this byte.
-
- dw 0 ;+ Reserved 45 e1
- ; Holds the current directory entry number. Lower
- ; two bits are the search return code.
-
- dw 0 ;+ Search FCB address 47 e3
- ; Holds the FCB address of the last search for
- ; first/next operation.
-
- db 0 ;+ Search type flag 49 e5
- ; 0=? in drive code search.
- ; 0fh=normal search.
-
- db 01 ;* BDOS Multi-Sector Count. 4a e6
- ; This field is set by BDOS Function 44, Set Multi-
- ; Sector Count.
-
- db 0 ;* BDOS Error Mode. 4b e7
- ; This field is set by BDOS Function 45, Set BDOS
- ; Error Mode. If this byte is set to 0ffh, the
- ; system returns to the current program without
- ; displaying any error messages.
-
-
- db 0 ;* Drive Search Chain 1 4c e8
- db 0ffh ;* Drive Search Chain 2 4d e9
- db 0ffh ;* Drive Search Chain 3 4e ea
- db 0ffh ;* Drive Search Chain 4 4f eb
-
- db 0 ;* Temporary File Drive 50 ec
-
- db 0 ; Error Drive. 51 ed
- ; This byte contains the drive number of the selected
- ; drive when the last physical or extended error
- ; occured.
-
- db 0 ; Reserved 52 ee
- db 0 ; Reserved 53 ef
-
- db 0 ; Media Flag 54 f0
- ; This flag may be set by the BIOS to indicate that
- ; a drive door has opened thus signalling the BDOS
- ; to relog the drive if required.
- db 0 ; Reserved 55 f1
- db 0 ; Reserved 56 f2
-
- db 080h ; BDOS Flags. 57 f3
- ; bit 7= expanded error messages
- ; 6= single byte allocation vectors
-
- dw 0ffffh ;* Date in days in binary since 1 Jan 78 58 f4
- db 0ffh ;* Hour in BCD 5a f6
- db 0ffh ;* Minutes in BCD 5b f7
- db 0ffh ;* Seconds in BCD 5c f8
-
- COMBASE:
- dw 0 ; Common Memory Base address 5d f9
- ; This value is zero for nonbanked systems, and
- ; nonzero for banked systems. Because the base
- ; address must reside on a page boundary, the
- ; first byte will always be 0. The second byte
- ; is the important one being the common memory
- ; base page.
-
- jp bnkdos2 ; Pointer to second entry in banked DOS 5f fb
- ; This entry handles the displaying of errors to
- ; the user
-
- dw start ; Top of user TPA 62 fe
- ; This word always reflects the top of TPA and
- ; should be the same as the word at 0006h unless a
- ; transient changes (0006h) without knowing about
- ; this word
