Using CP/M

CP/M Quick Reference 
Control key commands
 
 
 
CTRL + C
Restarts CP/M by initiating a warm start
CTRL + E
Forces the cursor to the next line of the screen for continued command line input.
CTRL + H
Moves the cursor one space to the left in the same manner as the BS key.
CTRL + I
Inputs a tab code (same as the TAB key)
CTRL + P
Turns on or off the printer echo function. When the printer echo function is turned on, data displayed on the LCD screen is output to the printer (or other device assigned to LST:) each time the RETURN key is pressed. The printer echo function is turned on by pressing CTRL + P once and is turned off when CTRL + P is pressed a second time. (Make sure the printer is connected properly before using this command.)
CTRL + R
Redisplays the contents of the current command line.
CTRL + S
Momentarily stops processing currently being performed (same as the PAUSE key). Processing can be resumed by inputting this command again.
CTRL + U
Cancels the current command line and moves the cursor to the next line on the screen for input of a different command.
CTRL + X
Erases the current command line and moves the cursor back to the beginning of the line.
CTRL + Z
Terminates input from the keyboard (used in combination with certain CP/M transient commands).
Commands
d: - A drive letter
filematch - an exact filename, or a wildcard match for files.
Items such as 
[item] are optional, ones such as 
<item> are compulsory.
DIR [d:][filematch]
Display a list of files in the specified, or current drive.
ERA [d:]<filematch>
Erase specified files. filematch *.* can be used to match all files in the current drive.
REN [d:]newname.ext = oldname.ext
Change the name of a disk file from oldname.ext to newname.ext
SAVE n [d:]filename.ext
Save the specified n number of pages of the transient program area to disk under the specified file name.
TYPE [d:]filename.ext
Display the contents of the specified file on the display screen. Display is only meaningful if the file contents was ASCII text.
USER n
Switches to the specified user area in a disk drive.
A user area is a physical area on a disk which has its own directory and which is managed separately from the rest of the disk. Data cannot be read from or written to any user area other than that in which CP/M is currently operating. A disk can be divided up into a maximum of 16 user areas.
PIP
Copy 
FOO.TXT to console (print).
C:PIP CON:=A:FOO.TXT
Write to file from terminal (
CTRL-Z to 
EOF, 
CTRL-M+J for new line):
C:PIP FOO.TXT=CON:
Copy file from current drive to 
A:
C:PIP A:UPLOAD.COM=UPLOAD.COM
ED
http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch2.htm 
Commands mode
#a
load all lines from file (given as arg to the command) to memory
10a
load 10 lines from file
b#t
go to beginning, print all lines
b
go to beginning
n or 
-n
move n lines ahead/behind and print
t
print current line
k
kill current line
i
insert before current line
e
save and exit
o
discard changes
In insert mode
CTRL + H
backspace one char
CTRL + Z
exit insert mode
ASM
http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch3.htm#Section_3.6
Compile and run 
example program:
c:asm example
c:load example
example
Show compiled program listing:
type example.prn
Compiler output line markers
S
syntax error
L
bad label
E
bad expression
R
bad register
Y
bad value
API
https://www.seasip.info/Cpm/bdos.html
https://obsolescence.wixsite.com/obsolescence/cpm-internals
http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch5.htm
Entry point: 
05h (
CALL 05h).
Memory map
File Control Block
FCB start: 
5Ch (not 
60h as in the picture).
Address
Field
Definition
FCB+00h
dr
drive code (0-16)
0 = use default drive for file
1 = auto disk select drive A,
2 = auto disk select drive B,
    ...
16 = auto disk select drive P.
FCB+01h
f1...f8
contain the filename in ASCII upper-case, with high bit = 0
FCB+09h
t1,t2,t3
contain the filetype in ASCII upper-case, with high bit = 0. t1', t2', and t3' denote the bit of these positions,
t1' = 1 = Read-Only file,
t2' = 1 = SYS file, no DIR list
FCB+0Ch
ex
contains the current extent number, normally set to 00 by the user, but in range 0-31 during file I/O
FCB+0Dh
s1
reserved for internal system use
FCB+0Eh
s2
reserved for internal system use, set to zero on call to OPEN, MAKE, SEARCH
FCB+0Fh
rc
record count for extent ex; takes on values from 0-127; Set this to 0 when opening a file
FCB+10h
d0...dn
filled in by CP/M; reserved for system use
FCB+20h
cr
current record to read or write in a sequential file operation; normally set to zero by user after opening file
FCB+21h
r0,r1,r2
optional random record number in the range 0- 65535, with overflow to r2, r0, r1 constitute a 16-bit value with low byte r0, and high byte r1
File Buffer start: 
80h (128 bytes long).
Notes
When running command in CP/M with file path as first argument the drive number and file name are set in default FCB automatically before program runs.
When two arguments are given another drive number and file name are set starting from absolute 
6Ch. It will be overwritten by file operations.
If no arguments are given the FCB file name is all blank/space characters (
 )
Command line arguments are also available from 
80h (File Buffer).
Useful constants:
FCB       EQU  5Ch     ; File Control Block
FCBFNAME  EQU  FCB+01h ; FCB File Name
FCBEX     EQU  FCB+0Ch ; FCB Excent Number
FCBRC     EQU  FCB+0Fh ; FCB Record Count
FCBCR     EQU  FCB+20h ; FCB Current Record
FB        EQU  80h     ; File Buffer
CP/M procedures
Function
Number
Function
Name
Input
Output
Dec
Hex
0
0
System Reset
none
none
1
1
Console Input
none
A = ASCII char
2
2
Console Output
E = char
none
3
3
Reader Input
none
A = ASCII char
4
4
Punch Output
E = char
none
5
5
List Output
E = char
none
6
6
Direct Console I/O
E = 0FFH (input)
A = char
E = 0FEH (status)
A = status
E = char
none
7
7
Get I/O Byte
none
A = I/O byte value
8
8
Set I/O Byte
E = I/O byte
none
9
9
Print String
DE = Buffer Address
none
10
A
Read Console String
DE = Buffer
Console characters in Buffer
11
B
Get Console Status
none
A = 00/non zero
12
C
Return Version #
none
HL = Version #
13
D
Reset Disk System
none
none
14
E
Select Disk
E = Disk #
none
15
F
Open File
DE = FCB address
A = FF if not found
16
10
Close File
DE = FCB address
A = FF if not found
17
11
Search For First
DE = FCB address
A = Directory Code
18
12
Search For Next
none
A = Directory Code
19
13
Delete File
DE = FCB address
A = none
20
14
Read Sequential
DE = FCB address
A = Error Code
21
15
Write Sequential
DE = FCB Address
A = Error Code
22
16
Make File
DE = FCB address
A = FF if no DIR Space
23
17
Rename File
DE = FCB address
A = FF if not found
24
18
Return Login Vector
none
HL = Login Vector*
25
19
Return Current Disk
none
A = Current Disk Number
26
1A
Set DMA Address
DE = DMA address
none
27
1B
Get ADDR (ALLOC)
none
HL = ALLOC address*
28
1C
Write Protect Disk
none
none
29
1D
Get Read/only Vector
none
HL = ALLOC address*
30
1E
Set File Attributes
DE = FCB address
A = none
31
1F
Get ADDR (Disk Parms)
none
HL = DPB address
32
20
Set/Get User Code
E = 0FFH for Get
A = User Number
E = 00 to 0FH for Set
none
33
21
Read Random
DE = FCB address
A = Error
34
22
Write Random
DE = FCB address
A = Error Code
35
23
Compute File Size
DE = FCB address
r0, r1, r2
36
24
Set Random Record
DE = FCB address
r0, r1, r2
37
25
Reset Drive
DE = Drive Vector
A = 0
38
26
Access Drive
not supported
39
27
Free Drive
not supported
40
28
Write Random w/Fill
DE = FCB
A = error code
Reading file
Given file name in the arguments one can first check if argument was given by checking for space character in 
FCBFNAME (
FBC + 01h).
If file name is filled we can open the file:
     XOR  A
     LD   (FCBEX),A   ; select 0'th extent
     LD   (FCBRC),A   ; clear
     LD   (FCBCR),A   ; clear
     LD   C,FOPE      ; open file
     LD   DE,FCB      ; use default FCB
     CALL BDOS
Set EX, RC and CR to 
0 and call File Open (
0Fh). A will contain 
FFh if file was not found.
Next file can be read:
     XOR  A
     LD   (FCBCR),A ; start from beginning
     LD   C,FRED    ; read file
     LD   DE,FCB    ; use default FCB
     CALL BDOS
Set CR to 
0 to start reading from beginning of the file and call Read Sequential (
14h). A is set to 
0 if read was successful.
128 bytes was read to FB (starting at 
80h). CR (and EX) will be automatically incremented, so calling Read Sequential again will read next 128 byte of the file to FB.