OpenEuphoria

Re: External Modem Emulator

• Posted by Ben Logan <wbljr79 at HOTMAIL.COM> Jan 27, 2000
• 581 views

>From: JJProg at CYBERBURY.NET
>Reply-To: Euphoria Programming for MS-DOS <EUPHORIA at LISTSERV.MUOHIO.EDU>
>To: EUPHORIA at LISTSERV.MUOHIO.EDU
>Subject: Re: External Modem Emulator
>Date: Wed, 26 Jan 2000 19:00:46 EST
>
>EU>--Modem emulator...fools computer on other end of serial cable, into
>EU>thinking
>EU>--it owns an external modem.
>
>EU>--Anything that comes in com2 is sent out com1, and anything that comes
>in
>EU>--com1 is sent out com2.
>EU>--Some concepts are taken from E-TERM.EX--Thanks to PJB Systems
>EU>--Pressing any key breaks out of the program.
>
>EU>without type_check
>
>EU>include serial.e
>
>EU>integer key,data,rcnt
>EU>sequence rBuffer    rBuffer = {}
>
>EU>clear_screen()
>EU>puts(1,"Modem Emulator in operation...press a key to terminate...")
>
>EU>SetPortBPDS(1,19200,0,8,1)  --Configure the ports
>EU>SetPortBPDS(2,19200,0,8,1)
>
>EU>rcnt = 0
>EU>key = -1
>EU>while key < 0 do
>EU>    data = GetSerialByte(2)  --See if modem has sent any data
>EU>    if data > 0 then
>EU>        rBuffer &= data  --Yes, so put it in buffer
>EU>        rcnt = 200   --This must be 200 in order not to lose data
>EU>    else
>EU>        rcnt = rcnt -1
>EU>    end if
>EU>    if rcnt < 1 then
>EU>        rcnt = 0
>EU>        key = get_key()   --If user has pressed a key, then exit prog
>EU>        if length(rBuffer) > 0 then   --If there's anything in buffer,
>EU>            for i = 1 to length(rBuffer) do --Send it out
>EU>                SendSerialByte(1,rBuffer[i]) --com1
>EU>            end for
>EU>            rBuffer = {}  --Empty the buffer
>EU>        end if
>EU>        data = GetSerialByte(1) --Get data from com1 (remote 'puter)
>EU>        if data > 0 then    --If any data was waiting,
>EU>            SendSerialByte(2,data) --send it to modem
>EU>        end if
>EU>    end if
>EU>end while
>EU>puts(1,"\n\nDone.\n")
>EU>-------------------------------------------------
>
>EU>Thanks in advance,
>
>EU>Ben
>
>EU>______________________________________________________
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>
>Try writing as much in assembly as possible, so that it goes faster.
>For example, try this:
>
>push edx        ; Save the registers
>push eax
>mov dx, 765     ; COM2 data ready
>in al, dx
>and al, 1
>cmp al, 0       ; Is data ready?
>je noMoreData   ; No
>mov dx, 760     ; COM2 input
>in al, dx
>mov dx, 1016    ; COM1 output
>out dx, al
>noMoreData:
>pop eax         ; Restore registers and return
>pop edx
>ret
>
>I haven't tested it, though.
>
>Jeff

Looks like it will work, but I'm not sure how to implement it in Euphoria.
In particular, how do I know what address to poke in for a label when I
don't know where it will be loaded into memory.  I looked at Pete's asm.e,
but will it resolve the addresses?

Also, do you think that the assembly language code will be fast enough, that
I can eliminate the buffer?  If not, how do I add a byte to the sequence
(rBuffer in the above code) from the asm routine?

Thanks again,

Ben
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