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So far, this list covers CP/M 1, 2 and 3. "CP/M 3 and above" means:
To make a BDOS call in an 8-bit CP/M, use:
LD DE,parameter LD C,function CALL 5and in a 16-bit CP/M, use:
MOV DX,parameter MOV CL,function INT 0E0hValues are returned in BA = HL (8-bit) / AX = BX (16-bit). is supported in DR Multiuser DOS.
The information in this list overlaps with the Interrupt List section on INT E0h to some extent.
Note that DOS + is a CP/M extended BDOS. For information on "DOSPLUS 1.2" and "Personal CP/M-86 v2.0/2" see those sections marked "CP/M-86 v4" (the underlying BDOS is version 4.1 in both cases).
If you have detailed information on MP/M, CP/Net, DOS Plus v2.1, CP/M-86 or Concurrent CP/M - let me know!
Entered with C=0. Does not return.
Quit the current program, return to command prompt. This call is hardly
ever used since the RST 0 instruction does the same thing and saves
four bytes.
Entered with CL=0, DL=0 or 1. Does not return.
Quit the current program, return to command prompt. If DL is 0, the memory used by the program is deallocated; if DL is 1, it remains resident.
Entered with C=1. Returns A=L=character.
Wait for a character from the keyboard; then echo it to the screen and return it.
Entered with C=2, E=ASCII character.
Send the character in E to the screen. Tabs are expanded to spaces. Output can be paused with ^S and restarted with ^Q (or any key under versions prior to CP/M 3). While the output is paused, the program can be terminated with ^C.
Entered with C=3. Returns A=L=ASCII character
Note that this call can hang if the auxiliary input never sends data.
Entered with C=4, E=ASCII character.
If the device is permanently not ready, this call can hang.
Entered with C=2, E=ASCII character.
If the printer is permanently offline or busy, this call can hang.
Entered with C=6, E=code. Returned values (in A) vary.
Values of E not supported on a particular system will output the character. Under CP/M 2 and lower, direct console functions may interact undesirably with non-direct ones, since certain buffers may be bypassed. Do not mix them.
Entered with C=7. Returns I/O byte.
Here's a description of how the IOBYTE works.
Entered with C=7. Returns A=0 or 0FFh.
0FFh is returned if the Auxiliary Input device has a character ready; otherwise 0 is returned.
Entered with C=8, E=I/O byte.
Here's a description of how the IOBYTE works.
Entered with C=8. Returns A=0 or 0FFh.
0FFh is returned if the Auxiliary Output device is ready for characters; otherwise 0 is returned.
Entered with C=9, DE=address of string.
Display a string of ASCII characters, terminated with the $ character.
Thus the string may not contain $ characters - so, for example, the VT52
cursor positioning command ESC Y y+32 x+32 will not be able to
use row 4.
Under CP/M 3 and above, the terminating character can be changed using BDOS function 110.
Entered with C=0Ah, DE=address or zero.
This function reads characters from the keyboard into a memory buffer until RETURN is pressed. The Delete key is handled correctly. In later versions, more features can be used at this point; ZPM3 includes a full line editor with recall of previous lines typed.
On entry, DE is the address of a buffer. If DE=0 (in CP/M-86 versions DX=0FFFFh), the DMA address is used (CP/M 3 and later) and the buffer already contains data:
DE=address: DE=0 / DX=0FFFFh: buffer: DEFB size buffer: DEFB size DEFB ? DEFB len DEFB bytes DEFB bytesThe value at buffer+0 is the amount of bytes available in the buffer. Once the limit has been reached, no more can be added, although the line editor can still be used.
If DE=0 (in 16-bit versions, DX=0FFFFh) the next byte contains the number of bytes already in the buffer; otherwise this is ignored. On return from the function, it contains the number of bytes present in the buffer.
The bytes typed then follow. There is no end marker.
Entered with C=0Bh. Returns A=L=status
Returns A=0 if no characters are waiting, nonzero if a character is waiting.
Entered with C=0Ch. Returns HL=0
Has no effect except to return HL=0.
Entered with C=0Ch. Returns B=H=system type, A=L=version number.
The system type is subdivided into a machine type and a CP/M type. The machine type occupies the high nibble of the byte; the CP/M type is a bitmapped field stored in the low nibble.
Machine types: CP/M types: Version numbers:
0 - 8080 Bit 0 set for MP/M 00h - Version 1 (see Lift Head above)
1 - 8086 Bit 1 set for CP/Net 20h - Version 2.0
(ie:network present) 21h - Version 2.1
Bit 2 set in 16-bit 22h - Version 2.2
multi-user OSes 25h - Version 2.5 (DOS +)
28h - Version 2.8 (Personal CP/M-80)
For plain CP/M, 30h - Version 3.0
the CP/M type is 0. 31h - Version 3.1
41h - Version 4.1 (DOSPLUS 1)
60h - Version 6.0 (DOSPLUS 2)
Confusingly, CP/M-86 v1.1 returns 0022h (ie, "8080 CP/M v2.2").
It is interesting to note that the version numbers returned by DRDOS and Novell DOS follow this system; DRDOS 5 is version 6.5, DRDOS 6 is version 6.7, Novell DOS 7 is version 7.2 and DR-OpenDOS is version 7.3.
Entered with C=0Dh. Returned values vary.
Resets disc drives. Logs out all discs and empties disc buffers. Sets the currently selected drive to A:. Any drives set to Read-Only in software become Read-Write; replacement BDOSses tend to leave them Read-Only.
In versions 1 and 2, logs in drive A: and returns 0FFh if there is a file present whose name begins with a $, otherwise 0. Replacement BDOSses may modify this behaviour.
Entered with C=0Eh, E=drive number. Returns L=A=0 or 0FFh.
The drive number passed to this routine is 0 for A:, 1 for B: up to 15 for P:.
Sets the currently selected drive to the drive in A; logs in the disc. Returns 0 if successful or 0FFh if error. Under CP/M 3 and later, H can contain a physical error number.
Entered with C=0Fh, DE=FCB address. Returns error codes in BA and HL.
This function opens a file to read or read/write. The FCB is a 36-byte data structure, most of which is maintained by CP/M. Look here for details.
The FCB should have its DR, Fn and Tn fields filled in, and the four fields EX, S1, S2 and RC set to zero. Under CP/M 3 and later, if CR is set to 0FFh then on return CR will contain the last record byte count. Note that CR should normally be reset to zero if sequential access is to be used.
Under CP/M 3 and later, a password can be supplied to this function by pointing the DMA address at the password.
On return from this function, A is 0FFh for error, or 0-3 for success. Some versions (including CP/M 3) always return zero; others return 0-3 to indicate that an image of the directory entry is to be found at (80h+20h*A).
If A=0FFh, CP/M 3 returns a hardware error in H and B. It also sets some bits in the FCB:
Entered with C=0Fh, DE=FCB address. Returns error codes in BA and HL.
This function is called with bit 7 of the FCB drive byte set, to distinguish it from a normal Open File call.
Byte 0Ch (Extent) of the FCB holds a subfunction code, 0-3:
Entered with C=10h, DE=FCB address. Returns error codes in BA and HL.
This function closes a file, and writes any pending data. This function should always be used when a file has been written to.
On return from this function, A is 0FFh for error, or 0-3 for success. Some versions always return zero; others return 0-3 to indicate that an image of the directory entry is to be found at (80h+20h*A).
Under CP/M 3, if F5' is set to 1 then the pending data are written and the file is made consistent, but it remains open.
If A=0FFh, CP/M 3 returns a hardware error in H and B.
Entered with C=10h, DE=FCB address. Returns error codes in BA and HL.
This function is called with bit 7 of the FCB drive byte set, to distinguish it from a normal Close File call.
This sets the current directory on the specified drive to the root directory.
Entered with C=11h, DE=address of FCB. Returns error codes in BA and HL.
Search for the first occurrence of the specified file; the filename should be stored in the supplied FCB. The filename can include ? marks, which match anything on disc. If the first byte of the FCB is ?, then any directory entry (including disc labels, date stamps etc.) will match. The EX byte is also checked; normally it should be set to zero, but if it is set to ? then all suitable extents are matched.
Returns A=0FFh if error (CP/M 3 returns a hardware error in H and B), or A=0-3 if successful. The value returned can be used to calculate the address of a memory image of the directory entry; it is to be found at DMA+A*32.
Under CP/M-86 v4, if the first byte of the FCB is '?' or bit 7 of the byte is set, subdirectories as well as files will be returned by this search.
Entered with C=12h, (DE=address of FCB)?. Returns error codes in BA and HL.
This function should only be executed immediately after function 17 or another invocation of function 18. No other disc access functions should have been used.
Function 18 behaves exactly as number 17, but finds the next occurrence of the specified file after the one returned last time. The FCB parameter is not documented, but Jim Lopushinsky states in LD301.DOC:
In none of the official Programmer's Guides for any version of CP/M does it say that an FCB is required for Search Next (function 18). However, if the FCB passed to Search First contains an unambiguous file reference (i.e. no question marks), then the Search Next function requires an FCB passed in reg DE (for CP/M-80) or DX (for CP/M-86).
Entered with C=13h, DE=address of FCB. Returns error codes in BA and HL.
Deletes all directory entries matching the specified filename. The name can contain ? marks. Returns A=0FFh if error, otherwise 0-3 (CP/M 3 returns a hardware error in H and B).
Under CP/M 3, if bit F5' is set to 1, the file remains but any password protection is removed. If the file has any password protection at all, the DMA address must be pointing at the password when this function is called.
Entered with C=13h, DE=address of FCB. Returns error codes in BA and HL.
This function is called with bit 7 of the FCB drive byte set, to distinguish it from a normal Delete File call.
If the specified subdirectory exists and is empty, removes it.
Entered with C=14h, DE=address of FCB. Returns error codes in BA and HL.
Load a record (normally 128 bytes, but under CP/M 3 this can be a multiple of 128 bytes) at the previously specified DMA address. Values returned in A are:
Entered with C=15h, DE=address of FCB. Returns error codes in BA and HL.
Write a record (normally 128 bytes, but can be a multiple of 128 bytes) to be found at previously specified DMA address. Values returned in A are:
Entered with C=16h, DE=address of FCB. Returns error codes in BA and HL.
Creates the file specified. Returns A=0FFh if the directory is full.
If the file exists already, then the default action is to return to the command prompt, but CP/M 3 may return a hardware error instead. Under CP/M 3, set F6' to create the file with a password; the DMA address should point at a 9-byte buffer:
DEFS 8 ;Password DEFB 1 ;Password mode
Entered with C=16h, DE=address of FCB. Returns error codes in BA and HL.
This function is called with bit 7 of the FCB drive byte set, to distinguish it from a normal Create File call.
Creates a new subdirectory in the current directory, with the given name.
Entered with C=17h, DE=address of FCB. Returns error codes in BA and HL.
Renames the file specified to the new name, stored at FCB+16. This function cannot rename across drives so the "drive" bytes of both filenames should be identical. Returns A=0-3 if successful; A=0FFh if error. Under CP/M 3, if H is zero then the file could not be found; if it is nonzero it contains a hardware error number.
Entered with C=18h. Returns bitmap in HL.
Bit 7 of H corresponds to P: while bit 0 of L corresponds to A:. A bit is set if the corresponding drive is logged in.
Entered with C=19h. Returns drive in A. Returns currently selected drive. 0 => A:, 1 => B: etc.
Entered with C=1Ah, DE=address.
Set the Direct Memory Access address; a pointer to where CP/M should read or write data. Initially used for the transfer of 128-byte records between memory and disc, but over the years has gained many more functions.
Entered with C=1Bh. Returns address in HL.
Return the address of the allocation bitmap (which blocks are used and which are free) in HL. Under banked CP/M 3, this will be an address in bank 0 (the system bank) and not easily accessible.
Under previous versions, the format of the bitmap is a sequence of bytes, with bit 7 of the byte representing the lowest-numbered block on disc, and counting starting at block 0 (the directory). A bit is set if the corresponding block is in use.
Under CP/M 3, the allocation vector may be of this form (single-bit) or allocate two bits to each block (double-bit). This information is stored in the SCB.
Entered with C=1Ch.
Temporarily set current drive to be read-only; attempts to write to it will fail. Under genuine CP/M systems, this continues until either call 13 (disc reset) or call 37 (selective disc reset) is called; in practice, this means that whenever a program returns to the command prompt, all drives are reset to read/write. Newer BDOS replacements only reset the drive when function 37 is called.
Entered with C=1Dh. Returns bitmap in HL.
Bit 7 of H corresponds to P: while bit 0 of L corresponds to A:. A bit is set if the corresponding drive is set to read-only in software.
Entered with C=1Eh, DE=address of FCB. Returns error codes in BA and HL.
Set and reset the bits required. Standard CP/M versions allow the bits F1', F2', F3', F4', T1' (read-only), T2' (system) and T3' (archive) to be changed. Some alternative BDOSses allow F5', F6', F7' and F8' to be set, but this is not to be encouraged since setting these bits can cause CP/M 3 to behave differently.
Under CP/M 3, the Last Record Byte Count is set by storing the required value at FCB+32 (FCB+20h) and setting the F6' bit.
The code returned in A is 0-3 if the operation was successful, or 0FFh if there was an error. Under CP/M 3, if A is 0FFh and H is nonzero, H contains a hardware error.
Entered with C=1Fh. Returns address in HL.
Returns the address of the Disc Parameter Block for the current drive. See the formats listing for details of the DPBs under various CP/M versions.
Entered with C=20h, E=number. If E=0FFh, returns number in A.
Set current user number. E should be 0-15, or 255 to retrieve the current user number into A. Some versions can use user areas 16-31, but these should be avoided for compatibility reasons.
DOS+ returns the number set in A.
Entered with C=21h, DE=FCB address. Returns error codes in BA and HL.
Read the record specified in the random record count area of the FCB, at the DMA address. The pointers in the FCB will be updated so that the next record to read using the sequential I/O calls will be the record just read. Error numbers returned are:
Entered with C=22h, DE=FCB address. Returns error codes in BA and HL.
Write the record specified in the random record count area of the FCB, at the DMA address. The pointers in the FCB will be updated so that the next record to write using the sequential I/O calls will be the record just written. Error numbers returned are:
Entered with C=23h, DE=FCB address. Returns error codes in BA and HL.
Set the random record count bytes of the FCB to the number of 128-byte records in the file. Returns A=0FFh if error (file not found, or CP/M 3 hardware error); otherwise A=0.
Entered with C=24h, DE=FCB address.
Set the random record count bytes of the FCB to the number of the last record read/written by the sequential I/O calls.
Entered with C=25h, DE=bitmap of drives to reset. Returns A=0.
Bit 7 of D corresponds to P: while bit 0 of E corresponds to A:. A bit is set if the corresponding drive should be reset. Resetting a drive removes its software read-only status.
Locks one or more disc drives. Processes attempting to use these drives will be blocked.
From the description, it would seem that DE holds a drive bitmap.
Releases locks on disc drives.
Entered with C=28h, DE=FCB address. Returns error codes in BA and HL.
As function 34, but if the write is to a newly allocated disc block the remainder of the block is filled with zeroes.
Entered with C=2Ch, E=number of records. Returns A=0 or 0FFh.
Sets the number of records that functions 14, 15, 31, 32 and 40 should attempt to read at once. E should be 1-127. Returns A=0 if E was valid, 0FFh otherwise. The random access counters still operate with 128 bytes/record.
Entered with C=2Dh, E=action.
Instructs CP/M 3 what action to take if there is a hardware error:
Entered with C=2Eh, E=drive. Returns error codes in BA and HL.
Sets the three bytes at the DMA address to the number of free 128-byte records on the disc, low byte first. E is the drive (0 for A:, 1 for B: etc.). If on return A=0FFh, there is a hardware error in H.
Entered with C=2Fh, E=chain flag. Does not return.
Execute the command line at 80h. The error return code is not changed, so the new program can discover the status returned by the previous one.
If E=255, then the currently set drive and user (as set by calls 25 and 32) become those used by the CCP; otherwise the CCP drive and user remain the same.
Entered with C=30h, E=flag. Returns error codes in BA and HL.
Forces all pending disc writes to be executed. If E=255, then all disc read buffers are emptied as well (so that information must be read from the disc - used by file verification programs).
Returns A=0FFh if there is a hardware error in H.
Entered with C=31h, DE=address of parameter area. Returned values vary.
The SCB is a 100-byte area of memory (officially) used for storing system settings. The parameter area is formed:
pb+0: DB offset ;0-99
pb+1: DB command ;0 => Read byte at offset into A,
; and word at offset into HL.
;0FEh => Write word at pb+2 to SCB at
; offset and offset+1
;0FFh => Write byte at pb+2 to SCB at offset
Entered with CL=31h. Returns address in ES:BX.
More information on the System variables area in CP/M-86.
Entered with CL=31h, DX=address of parameter area. Returned values vary.
The BDOS 4.1 system variables contain various system settings. The parameter area is formed:
pb+0: DB system variable ;0-5 pb+1: DB command ;0 => Read the specified variable into AL ;0FFh => Write data at pb+2 to specified variable.Variables are:
Number Length Description 0 1 screen width-1 1 1 screen height-1 2 1 page mode - 0 if programs like TYPE should give paged output 3 1 system clock speed in Hz. Cannot be changed. 4 1 temporary file drive, 0 for current or 1-16 for A: to P: 5 5 date and time DW day count, day 1 is 1/1/78 DB BCD hours DB BCD minutes DB BCD seconds
There are also some undocumented variables with numbers between 80h and 92h.
81h 1 Current process ID 82h 26 Data area for current process: DB drive DB user DD DMA DB current BDOS disc function DB ? DD FCB from the last BDOS search call DD ? DB Error mode (set by function 45). DB Multi-record count (set by function 44). DS 8 ;? 84h 1 Set if process is running in the background 86h 255 CCP settings area: DB CCP drive DB CCP user DB Cold start flag (0 if CCP has not run yet) DW Address of next command in CCP data segment DB Chained command flag (nonzero if a command is waiting) DB ? DB Search order (0=CMD 1=CMD,SUB 2=SUB,CMD) DB Program name display flag (1=yes 2=no) DS 7 ;? DB pending command? 87h 4 List of drives to search, set by SETDEF. 8Ah 1 Value set by SLICE - time slice to give to foreground program. 8Bh 2 BDOS flags. Bit 7 set if ^S is in operation. Bit 9 set if ^P is in operation. 8Ch 1 Flag connected with the numeric coprocessor 8Dh Address of code to run in task switch? 8Eh Pointer to array of 16 near pointers in CP/M data segment - addresses of current directory structures for each drive. 8Fh 5 Multitasker settings DW comsize ;Memory to give to COM files DW addmem ;Memory to give to EXE files DB f8087 ;8087 enabled or disabled? 90h 1 Drive containing COMMAND.COM? 91h 32 DOS 2.x Country Info (see the Interrupt List, INT 21h AH=38h) 92h 1 SwitChar (see the Interrupt List, INT 21h AH=37h). The SwitChar can only be changed this way.
Entered with C=32h, DE=address of parameter area. Returned values vary.
Under CP/M 3, the BIOS should not be directly called, except possibly the character I/O and USERF calls. Instead, this function should be used. The parameter area is formed:
pb+0: DB bios-function ;0-32 pb+1: DB bios-a ;Value for A register pb+2: DB bios-c ;Value for C register pb+3: DB bios-b ;Value for B register pb+4: DB bios-e ;Value for E register pb+5: DB bios-d ;Value for D register pb+6: DB bios-l ;Value for L register pb+7: DB bios-h ;Value for H registerUnder 16-bit versions, this function should be used for all BIOS calls; only character I/O BIOS calls are permitted. The parameter area is formed:
pb+0: DB bios-function pb+1: DB bios-cl pb+2: DB bios-ch pb+3: DB bios-dl pb+4: DB bios-dh
Entered with CL=33h, DX=segment value.
Entered with CL=34h. Returns address in ES:BX.
Entered with CL=35h, DX=address of MCB
Set MCB_EXT to 2 if the memory should remain allocated after program termination. Set MCB_LENGTH to maximum required length.
Returns MCB_EXT=0 if no additional memory is available, 1 if there is. Sets MCB_SEGMENT and MCB_LENGTH to the values for the memory block allocated, which will be less than or equal to the size requested. Returns AX=0 if OK, 0FFFFh if error; CX=error code:
0 OK 2 Illegal call number 3 Out of memory 12 Out of descriptors 43 Bad Parameter
Entered with CL=36h, DX=address of MCB
Set MCB_EXT to 2 if the memory should remain allocated after program termination. Set MCB_LENGTH to maximum required length, and MCB_SEGMENT to the required start paragraph.
Returns MCB_EXT=0 if no additional memory is available, 1 if there is. Sets MCB_SEGMENT and MCB_LENGTH to the values for the memory block allocated, which will be less than or equal to the size requested. Returns AX=0 if OK, 0FFFFh if error; CX=error code.
Entered with C=36h. Returns HL=address of stamp.
This returns the timestamp from the last file used by functions 15, 17 or 18. The format of a Z80DOS timestamp is:
DW creation date DW modification date DB modification time, hours, BCD DB modification time, minutes, BCD DW last access date DB last access time, hours, BCD DW last access time, minutes, BCD
More information on Z80DOS and ZPM3.
Entered with CL=37h, DX=address of MCB
Set MCB_EXT to 2 if the memory should remain allocated after program termination. Set MCB_LENGTH to maximum required length.
Returns MCB_EXT=0 if no additional memory is available, 1 if there is. Sets MCB_SEGMENT and MCB_LENGTH to the values for the memory block allocated, which will be exactly the size requested. Returns AX=0 if OK, 0FFFFh if error; CX=error code.
Entered with C=37h.
The next BDOS call will use the timestamp buffer returned by function 54, rather than the current time. This would normally done before creating or closing the file.
Entered with CL=38h, DX=address of MCB
Set MCB_EXT to 2 if the memory should remain allocated after program termination. Set MCB_LENGTH to maximum required length, and MCB_SEGMENT to the required start paragraph.
Returns MCB_EXT=0 if no additional memory is available, 1 if there is. Sets MCB_SEGMENT and MCB_LENGTH to the values for the memory block allocated, which will be exactly the size requested. Returns AX=0 if OK, 0FFFFh if error; CX=error code.
Entered with CL=39h, DX=address of MCB
Set MCB_SEGMENT to start of area, MCB_LENGTH to length. It is not possible to deallocate the middle or start of an area which was allocated as one piece. Set MCB_EXT to 0 to free the specified MCB, or 0FFh to free all this program's memory. Returns AX=0 if OK, 0FFFFh if error; CX=error code.
Entered with CL=3Ah. This function is obsolete in CP/M-86 v4. In CP/M-86 v1.1, it is called by the CCP to empty memory before a new program is loaded.
Entered with C=3Bh, DE=FCB address. Returns error code in A.
Load a program or RSX. The FCB should have been opened before making this call; the load address should be stored at FCB+21h. If the program is a PRL (Paged Relocatable), the original CP/M loader will relocate it; some replacement loaders, such as that in CCP+ need a special flag set to indicate this.
If DE=0, the Loader will not load anything, but it will remove from the RSX chain any RSXs marked as due for deletion.
Returns A=0 if OK, 0FEh if there was an error, or 0FFh if the Loader is not present.
Entered with C=3Ch, DE=RSXPB address
This call is provided for programs to communicate with Resident System Extensions. There is a separate list of functions provided by specific RSXs. The format of the RSXPB is:
DEFB function, 0-127 ;(128-255 used internally by CP/M) DEFB numwords ;Number of parameter words passed to RSX. DEFW parametersA popular convention is for the first parameter word to point to a copy within the program of the name of the intended RSX; for example:
RSXPB: DEFB 100 ;Function DEFB 1 ;1 Parameter DEFW RNAME ;RSX name RNAME: DEFB 'GETERL 'This call returns BA=HL=00FFh if the requested RSX is not resident; otherwise, the values are those returned by the RSX.
Entered with C=62h. Returns A=0 if OK, 0FFh if current drive is invalid
This function is called by the CCP when a program terminates. Open files are closed; buffered data are not written, so files opened for writing may be destroyed if not properly closed.
Entered with C=63h, DE=FCB address. Returns error codes in BA and HL.
Set the random record count of the FCB to the required file size in records. If the file is password protected, point the DMA address at the password. Returns A=0-3 for success, 0FFh for failure; H may contain a hardware error code.
Entered with C=64h, DE=FCB. Returns error codes in BA and HL.
The EX byte (FCB+0Ch) of the FCB should contain a flags byte:
Bit Meaning if set ---------------------------------------- 7 Passwords enabled 6 Stamp on access 5 Stamp on update 4 Stamp on creation 0 Assign password at DMA+8 to label.This function may need a password at the DMA address, if there is a label on the disc which has a password.
This function returns A=0 if OK, 0FFh for failure. H may contain a hardware error code.
Entered with C=65h, E=drive. Returns A=byte
The byte returned has the following bits set:
Bit Meaning if set ---------------------------------------- 7 Passwords enabled 6 Stamp on access 5 Stamp on update 4 Stamp on creation 0 Directory label existsIf bit 0 is zero, the other bits are meaningless.
If a label does exist, it can be found using functions 17 and 18 with the first 13 bytes of the FCB set to "?", and checking for a file whose user number is 32.
Entered with C=66h, DE=FCB address. Returns error codes in BA and HL.
Gets the file date and time stamps, and the password mode. The stamps end up at FCB+18h (create or access), FCB+1Ch (update); the password mode ends up at FCB+0Ch. This returns A=0-3 for success, or 0FFh for failure. To tell whether a stamp is for creation or access, check the directory label byte.
For information on the format of date and time stamps, see the date and time calls. The password mode is documented in the next function.
Entered with C=67h, DE=FCB address. Returns error codes in BA and HL.
Sets file password and protection mode. Set FCB+0Ch to the required password mode, and point the DMA address at the current password. The password mode byte should have the following bits set:
Bit Meaning if set ---------------------------------------- 7 Reading requires password 6 Writing requires password 5 Deletion requires password 0 Assign password at DMA+8 to file.
Entered with C=68h, DE=address of time stamp.
The format of the time stamp is:
DW day ;Day 1 is 1 January 1978 DB hour ;Packed BCD DB minute ;Packed BCD [ DB second ;Packed BCD; only on Z80DOS and DOS+ ]Under CP/M 3, the "seconds" counter will be reset to zero when this function is called. Under Z80DOS and DOS+, the "seconds" counter will be set from the time stamp.
Entered with C=69h, DE=address of time stamp. Returns A=seconds (packed BCD).
The format of the time stamp is:
DW day ;Day 1 is 1 January 1978 DB hour ;Packed BCD DB minute ;Packed BCD [ DB second ;Packed BCD - only in Z80DOS and DOS+]Under CP/M 3, the "seconds" value will be returned in A.
Entered with C=6Ah, DE=address of password.
Sets the default password, used for all file operations requiring passwords when no password is given explicitly.
Entered with C=6Bh, DE=address of buffer.
Stores a 6-byte serial number at the address given by DE. Usually this number will be printable ASCII.
Entered with C=6Ch, DE=code. Returns HL=code.
If DE=0FFFFh, then the current code is returned in HL. Otherwise, it is set to the value in DE. Allowable values are:
If the error code is 0FF00h or above, and the next command begins with the
character : then it will not be run.
Entered with C=6Dh, DE=mode or 0FFFFh. Returns HL=mode. The mode is a bitmapped value. Under CP/M 3, the significant bits are:
0 If set, function 11 detects only ^C.
1 If set, ^S does not pause screen output.
2 If set, output does not expand tabs, nor is it echoed to the printer even
if ^P was pressed.
3 If set, ^C does not cause the program to terminate.
4 Behaves like bit 2. The BDOS source comments imply it also signifies
"escape sequence decoding" but whatever this is, it is not implemented in
the CP/M 3 BDOS.
8 } These form a 2-bit number controlling GET and SUBMIT:
9 }
0 Return "conditional" status to function 11.
Programs using function 11 to test for interruption (eg SID) are
not interrupted, but those using it to test for input do get the
input. It does this by returning "false", then "true".
1 Function 11 always returns "true".
2 Function 11 always returns "false".
3 Temporarily disable GET/SUBMIT, input comes from keyboard.
Under Personal CP/M, only one bit is used:
4 If set, tab expansion, ^S and ^P are disabled during screen output.
Entered with C=6Eh, DE=0FFFFh or ASCII value. Returns ASCII value in A.
This function gets or sets the string delimiter (used in function 9 to mark the end of the string to print). If DE=0FFFFh, this gets the current ASCII value into A; otherwise it sets the delimiter to the value in E.
Entered with C=6Fh, DE=address of character control block.
For 8-bit CP/M, the character control block is formed:
DW text_begin DW text_lengthFor 16-bit CP/M, it is formed:
DW text_begin_offset DW text_begin_segment DW text_length
Entered with C=70h, DE=address of character control block.
Format of character control block
This function is passed straight to the BIOS.
Entered with C=73h, DE=parameter block address.
Follow this link for more information on the GSX calls.
Entered with CL=74h, DX=FCB address. Returns AX=BX=error code.
The required stamps should be put at the DMA address. Returns AL = 0-3 for success, or 0FFh for failure.
Entered with CL=75h, DX=PB address. Returns AX=BX=error code.
This appears to make a call to the disc drivers; INT 13h calls are routed through this function. The parameter block is:
DB 0 to read, 1 to write (2 to verify?) DB drive DB no. of sectors DB head DB sector (0 based) DB cylinder DD address of data
This call is passed directly to the BIOS.
This call is passed directly to the BIOS.
Entered with C=8Dh, DE=no. of ticks to wait.
Delays calling process out for DE ticks of the system clock (system dependent; usually 50Hz or 60Hz). Returns A=0FFh if this function is unsupported.
Entered with C=8Eh.
Relinquishes the CPU. The process restarts when its next time slice falls due. Returns A=0FFh if this function is unsupported.
Entered with C=8Fh.
As function 0.
Entered with C=92h.
Blocks the calling process until the system console is available. This is automatically called if any console I/O function is used while the current process is not attached to the console.
Entered with C=93h.
The program is disconnected from the screen and keyboard and must run in the background.
Under CP/M-86 v4, attempting to use the keyboard will cause the program to
be terminated. Note that backgrounded programs cannot use the
INT 2nh DOS-like calls, only the
INT E0h CP/M calls.
Limited screen output can be achieved using XIOS function 8 (write to status
line).
Under MP/M and CCP/M, attempting to output to the screen will cause function 146 to be invoked.
Entered with C=98h, DE=address of PFCB. Returns codes in HL.
This parses an ASCII filename to a FCB. The format of the PFCB is:
DEFW ascii-address DEFW fcb-addressThe value returned in HL is 0FFFFh if the ASCII filename was invalid; 0 if the ASCII filename was terminated with a zero or a carriage return; and otherwise the address of the next character after the filename.
The filename can be of any form up to the full d:filename.typ;password (password only under CP/M 3 and above). When the filename is parsed, the password is copied to FCB+10h, with its length at FCB+1Ah.
Under ZPM3, the filename may be of the form du:filename.typ;password; FCB+0Dh will be 0 if no user number was specified, or 1+number otherwise. If a Z-System is loaded, ZPM3 can also parse filenames of the form dir:filename.typ;password.
BUG: ZPM3 (version N10) puts the password at FCB+0Ch rather than FCB+10h, overwriting the user number stored at FCB+0Dh. It does not zero the last four bytes of the FCB, while CP/M does.
The filename can be terminated by any of:
space tab cr nul ; = > < . : , [ ] / | .
Entered with C=9Ah. Returns HL (or ES:BX) = system data address.
Entered with C=9Eh.
Blocks the calling process until the default printer is available. This is automatically called if any printer function is used while the current process is not attached to the printer.
Entered with C=9Fh.
Detach this process from the printer,
This has the same functionality under P2DOS as function 105 does under Z80DOS and DOS+.
Used by P2DOS, SUPRBDOS, NovaDOS.
This has the same functionality under P2DOS as function 104 does under Z80DOS and DOS+.
Used by P2DOS, SUPRBDOS, NovaDOS.
Entered with C=0D2h, E=number, 0-5. Returns values in BA and HL.
Suitable arguments are:
0. Return base address for BDOS module. Used for dynamic reconfiguration. 1. Return the current DMA setting. 2. Flush any console input pending, emptying all buffers. Returns 0. 3. Returns list device status (ready/not ready) 4. Returns punch " " " 5. Returns reader " " "
Arguments 3 to 5 represent ready as 0ffh, not ready as 0. If no custom installation for punch/reader device status has been made their status is returned 0 (not ready). Other arguments return 0.
Entered with C=0D3h, DE=decimal number.
Outputs the number as an unsigned 16-bit integer, with leading zero suppression.