Date   : Thu, 28 Jan 1993 20:51:00 GMT
From   : pbricker@rdth2.rdth.luc.edu (Preston Bricker)
Subject: BDOS calls

I cannot find who requested it, but here are CP/M BDOS functions
as best as I can read Sol Libes' pocket guide.

Func #                 Value Passed              Value Returned
in C reg               in DE or E reg            in A or HL reg

Peripheral I/O
 0 00 system reset           --                    --
 1 01 console read           --                    char
 2 02 console write          E=char                --
 3 03 reader read            --                    char
 4 04 punch write            E=char                --
 5 05 list write             E=char                --
 6 06 direct con IO (V2.x)   E=FFh (input)         char
                             E=char (output)       0=not ready
 7 07 get IOBYTE             --                    IOBYTE
 8 08 set IOBYTE             E=IOBYTE         
 9 09 print string           string addr           --
10 0A read console buffer    addr of data buffer   --
11 0B get console status     --                    00h=not ready
                                                   FFh=ready
Disk I/O
12 0C lift head (V1.x)       --                    --
      get version (V2.x)     --                    HL=vers no.
13 0D reset disk**           E=drive no.           --
14 0E select disk            E=drive no.           --
15 0F open file              -                     --
16 10 close file              |-FCB addr
17 11 search for file        -                      -dir
18 12 search for next         |  --               -| 00h valid, FFh not found
19 13 delete file             |                     -*
20 14 read next record        |-FCB addr
21 15 write next record       |
22 16 create file            -                     dir; FFh=disk full
23 17 rename file            old file FCB addr     dir; FFh=disk full
24 18 get login vector       -- (V1.4)             HL=drive code
25 19 get disk number        --                    A=cdn
26 1A set DMS addr.          DMA addr              --
27 1B get alloc. vector      --                    HL=alloc vector

V2.x only
28 1C write protect          --                    --
29 1D get R/O vector         --                    HL=R/O vector
30 1E set file attrib.       FCB addr              dir code
31 1F get addr. disk parms.  --                    HL=disk parm blk addr
32 20 get/set user code      E=FFh (get)           current code
                             E=user code (set)     --
33 21 read random                                  error code***
34 22 write random           -|FCB addr            error code***
35 23 compute file size      -|r0,r1,r2 fmt        random record field set
36 24 set random record                            random record field set

V2.2 & later
37 25 reset drive            drive vector          0
40 28 write random zero fill FCB addr              return code

not used
38 26
39 27

*   V1.4 none
**  V1.4 initializes system and selects A drive
*** error codes 01 - reading unwritten data
                03 - cannot close current extent
                04 - seek to unwritten extent
                05 - directory overflow (write only)
                06 - seek past physical end of disk
char=character
addr=address
dir =directory code
cdn =current drive number (A=0)
dpba=disk parameter block address

pbricker@rdth2.rdth.luc.edu