ZNOS BDOS Function Calls
                                ========================

On entry:  C=function,  DE=parameters
On exit:   All registers changed except IX, IY, A=L and B=H
           If call unsupported, A=0, HL=0

Some standard CP/M calls are modified to indicate that ZNOS is the BDOS.

Filenames are translated back and foreward between CP/M "filename.ext" and NetFS
"ext.filename". That is, CP/M files are stored on the host filing system in
subdirectories of the CP/M extension. The CP/M file attributes are [not yet
investigated].


                             ZNOS BDOS Function Call Summary
                             ===============================

HEX DEC FUNCTION                    ENTRY              RETURNED
-------------------------------------------------------------------------------------------
&40 64 Network Transmit             IX=>...
&41 65 Poll Transmit
&42 66 Open Receive Block
&43 67 Poll Receive
&44 68 Delete Receive Block
&45 69 Read Argument Block
&46 70 Read/Write NetFS Info
&47 71 Make Net_FSOp call
&48 72 OSCLI                        DE=>command line   A=0 ok, A<>0 error, HL=>error string
&49 73 ROFF                         -
&4A 74 Return ZNOS version string   -                  HL=>version string
&4B 75 Delete all receive blocks    E=action           A=status
&4C 76 Unsupported                  -                  A=0, HL=0
&4D 77 Unsupported                  -                  A=0, HL=0
&4E 78 Unsupported                  -                  A=0, HL=0
&4F 79 Unsupported                  -                  A=0, HL=0
&50 80 Unsupported                  -                  A=0, HL=0
&51 81 Unsupported                  -                  A=0, HL=0
&52 82 Unsupported                  -                  A=0, HL=0
&53 83 Unsupported                  -                  A=0, HL=0
&54 84 Unsupported                  -                  A=0, HL=0
&55 85 Unsupported                  -                  A=0, HL=0
&56 86 Unsupported                  -                  A=0, HL=0
&57 87 Unsupported                  -                  A=0, HL=0
&58 88 Something with a FCB         IX=>...
&59 89 Save whole file              DE=>FCB, DMA=addr  A=0 ok, A<0 error
                                    IX=length/128      HL=end addr
&5A 90 Load whole file              DE=>FCB, DMA=addr  A=0 ok, A<0 error
-------------------------------------------------------------------------------------------


                             ZNOS BDOS Function Call Details
                             ===============================

ZNOS call &40 - Network transmit
ZNOS call &41 - Poll Transmit
ZNOS call &42 - Open Receive Block
ZNOS call &43 - Poll Receive
ZNOS call &44 - Delete Receive Block
ZNOS call &45 - Read Argument Block
ZNOS call &46 - Read/Write NetFS Info


ZNOS call &47 - Make Net_FSOp call
----------------------------------
This sends a FSOp command to the current file server.


ZNOS call &48 - Make non-intercepted OSCLI call
-----------------------------------------------
On entry, DE =>command line
On exit,  A  =&00 ok, <>&00 error, HL=>error string, terminated with <CR>

This ensures NetFS is selected, sets up an error handler, and passes the command line
at DE to OSCLI. If no error occurs, A is returns holding &00; if an error occurs, A
is returned holding the error number, and HL points to the CR=terminated error string.


ZNOS call &49 - Disconnect remote connection
--------------------------------------------
This disconnects any remote connection by calling OSBYTE &33, the same as *ROFF.


ZNOS call &4A - Return ZNOS version string
------------------------------------------
On exit,  A = &00
          HL=>version string, terminated with '$'


ZNOS call &4B - Delete all receive blocks
-----------------------------------------


ZNOS call &58
-------------


ZNOS call &59 - Save whole file
-------------------------------
On entry, DE =>FCB
          DMA=address to save from
          IX =number of 128-byte blocks
          Flags in FCB:

On exit,  A  =&00 loaded ok
          HL =address after end of file
          A  =&FF file not found

This attempts to save the whole file specified in the FCB from memory starting at the DMA
address, with the length in 128-byte blocks specified in IX. Errors are trapped and returned.


ZNOS call &5A - Load whole file
-------------------------------
On entry, DE =>FCB
          DMA=address to load to
          Flags in FCB:

On exit,  A  =&00 loaded ok
          HL =address after end of file
          A  =&FF file not found

This attempts to load the whole file specified in the FCB into memory at the DMA address.
Errors are trapped and returned.


                         ZNOS-Specific CP/M Function Call Details
                         ========================================

Select Drive
Open
Close
Search First
Search Next
Delete
Read Sequential
Write Sequential
Make File
Rename File
Get Allocation Vector
Set File Attributes
Get Disk Parameter Block
Read Random
Write Random
Compute File Size
Set Random Record
Write Random with Zero Fill