🚀 go-pugleaf

   I'm trying to use the ROM-BIOS service to control the printer port.
Basically I just want to send out a streem of characters at high
speed. I'm trying to use the interrupt call 17H to send out my bytes -
but it dosen't work properly. My test program looks like this :


code  segment
      assume cs:code

start:  mov  ah,01h    ;+ Initializing printer.
        int  17h       ;-
        mov  ah,00h    ;+ Send out one byte.
        mov  al,34h
        int  17h       ;-
        mov  ah,00     ;+ Send out one more byte ..
        mov  al,44h    
        int  17h       ;-
        mov  ah,4ch    ;+ Terminate program.
        int  21h

code    ends

        end  start


  I'm compiling this program using IBM's macro assembler and then
using IBM's linker. Everything seems fine - and when I load the
program into the debugger the program is there all right. I can then
step trough the program or run the program in the debugger without any
problems - it's working just fine (I'm monitoring the port with a
logic analyzer). But when I'm running the COM file or the EXE file
from the DOS shell nothing happens - I get the control back without
any problems though. When I compile other programs using other BIOS
calls I have no problems !! 

  I've tryed to poll the printer status after sending a byte out, I've
tryed to insert delay's after sending a byte - It dosen't help.

  I'm using an IBM system/2, model 50.

  I would be very greatful if anybody could direct me to what I'm
doing wrong - and/or suggest any other method. It is my impression
that using the DOS printer output function (21H - AH=05H) is much more
slow, and I need speed.

                                         Thanks in advance,
                                                            Rolf.

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Rolf Toft.
Display Development Grp.
Sony Corporation.
6-7-35 Kitashinagawa, Shinagawa-ku,
Tokyo 141 Japan.
Tel : 81-3-3448-7952.  Fax: 81-3-3448-4249.  Email:toft@ddg.sony.co.jp
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