Mac65 Code to watchdog a modem

[rickcollette]

I am attempting to write some mac65 code that will watch a modem to find the state.
Use case: BBS program where a user unceremoniously hangs up; or if a program crashes and there is no recent activity on the modem because of that.
The idea is to run this as a TSR; and if the modem goes into a non-active state, execute a BASIC program.

My code does not work.  It compiles to an OBJ file, and I can execute it - but as soon as I try to take a peek at the memory location to see what the state is froma BASIC program, the system crashes nastily.

 

1000 START:
1010     JSR OPEN_RS232
1020     JSR MONITOR_STATUS
1030     JSR CLOSE_RS232
1040     JMP END_PROGRAM
2000 OPEN_RS232:
2020     RTS 
3000 CLOSE_RS232:
3020     RTS 
4000 MONITOR_STATUS:
4010     LDX #2
4020     LDA #7
4030     STA IOCB2+2
4040     JSR XIO_COMMAND
4050     LDA $02EA
4060     STA STATUS_BYTE
4070     RTS 
5000 XIO_COMMAND:
5010     JSR XIO_ENTRY
5020     LDA IOCB2+4
5030     CMP #0
5040     BNE HANDLE_ERROR
5050     RTS 
6000 HANDLE_ERROR:
6010     LDX # <ERROR_MSG
6020     LDY # >ERROR_MSG
6030     JSR PRINT_STRING
6040     RTS 
7000 PRINT_STRING:
7010     LDA #9
7020     STA IOCB2
7030     LDY #0
7040     JSR CIOV
7050     RTS 
8000 ERROR_MSG:
8010     .BYTE "ERROR OCCURRED",$9B,0
9000 END_PROGRAM:
9020     RTS 
10000 IOCB2 = $0350
10010 XIO_ENTRY = $E456
10020 CIOV = $E456
10030 STATUS_BYTE = $0680
11000    .END 

 

[TGB1718]

Shouldn't the X register hold the IOCB number * 16

from your code, the X register is holding the value 2 instead of 32 ($20)

[phaeron]

Several problems:

• MONITOR_STATUS passes X=2 to CIOV. This is an invalid value; X should be set to $10*IOCB#, so for IOCB#2 it would be X=$20.
• IOCB#2 isn't opened to any device before the status command is issued. You can do this by an "implied OPEN", but it requires pointing ICBAL,X and ICBAH,X to the device name (presumably R:).
• IOCB2 actually points to IOCB #1. IOCB#0 starts at $0340, IOCB#1 at $0350, and IOCB#2 at $0360.
• XIO_COMMAND is trying to read the buffer address low byte (ICBAL) instead of result status (ICSTA), and treats all non-zero status values as errors. Success is indicated by a positive number with $01 in most cases, with a few other values occasionally ($03 in particular from DOS).
• PRINT_STRING writes the $09 command byte into the device ID byte of IOCB#1 instead of the command byte of IOCB#0, and sets Y=0 instead of X=0 to select IOCB#0.
• HANDLE_ERROR doesn't write its string address into the ICBAL/ICBAH fields that would be necessary to tell CIO the address of the buffer to write.
• You have to set a maximum buffer length for the PUT RECORD command ($09) in ICBLL/ICBLH. CIO stops either after the EOL or at the end of the buffer, whichever comes first.

[rickcollette]

awesome - I am digging in using you folks comments.
I have applied some - and I'm getting freezing, but it does seem to get past some of the earlier issues.

 

[rickcollette]

I think im gonna step away from this. Super far out of my element.
Really - I just want a way to make sure a modem is working properly and still connected while loading and unload basic programs.

If it could be extended to also hold some string values i can read via USR/PEEK, that would be excellent.  

However, this is just so far outside my skillset - I think Ill try to find another approach

Appreciated the help here.

 

[TGB1718]

1 hour ago, rickcollette said:

However, this is just so far outside my skillset - I think Ill try to find another approach

@rickcollette

Could try this from BASIC, you can do what you wanted before but using PEEK and POKE plus a USR call

have a look at this listing, not tried it as I don't have an "R:" device, but I think the basics (excuse the pun) are there.

 

1 REM SIMPLE BASIC PROGRAM TO OPEN
2 REM R: DEVICE, THEN SET PARAMETERS
3 REM WITH POKES, THEN USE USR ROUTINE
4 REM TO CALL CIO
5 REM USR=PLA PLA PLA TAX JSR E456 RTS
10 DIM A$(8):RESTORE 1000
15 REM USR ROUTINE TO CALL CIO
20 FOR I=1 TO 8:REM INSERT INTO A$
30 READ A:A$(I,I)=CHR$(A)
40 NEXT I
50 CLOSE #2:REM JUST IN CASE IT'S OPEN
60 OPEN #2,12,0,"R:":REM OPEN R/W
70 REM POKE PARAMETERS INTO IOCB2
80 REM ADDRESS 864 TO 879
90 REM THEN USE:-
100 REM X=USR(ADR(A$),32)
110 REM TO CALL CIOV
120 REM YOU CAN THEN PEEK(746) FOR
130 REM THE STATUS BYTE (DVSTAT)
900 CLOSE #2:REM REMEMBER TO CLOSE
999 REM USR DATA
1000 DATA 104,104,104,170,32,86,228,96

 

[rickcollette]

this is perfect - I just need a way to create a persisted set of data across loading various programs.

ex: run program1.bas
  - this would load in a config file, stuff some values into peekaboo memory
  - provide a menu the user can select from
    - assume user selects "program2.bas"
program2.bas
  - Reads data from memory locations set by program1
  - maybe update those locations with its own information
  - user can return to program1
program3.bas
  - same thing as 2.. and so on.

use case: with a bbs, AMP and MOE did this - however the source to those is unavailable, and if it were, I don't think "we" have permission to mod and use it.
So - id like a startup program that reads and sets info to memory locations.
  - launch additional programs that use that data
  - information that would need to persist without having to recode everything to read a drop file or some such thing
    - I *COULD* use drop files that contain the data.. but what a PITA to have to rewrite all that code for each additional program...