Stuart's MDOS TIPI Browser for Geneve - MDOS Mode

+9640News · February 20, 2023

Stuart Conner's Web Browser for the TI-99/4A and MDOS
=====================================================

MDOS Version: 9.4g Assembly Date 2/18/2023

Stuart released his web browser for the TI-99/4A and TIPI over a year ago. I
made an inquiry with Stuart about the possibility of converting his web browser
source code to work with the Geneve 9640. Stuart had previously shared an
earlier version of his soure code for a RS232 telnet based access. When he had
posted he was working on a TIPI version, I waited until I had free time to work
on the project.

Stuart was gracious and was willing to share his source code. After 4 weeks of
reviewing over 4,000 lines of code, I have to my knowledge, converted his
program to run under MDOS.

To give an idea of what was required, the easiest was modifying the video
routines to use the Geneve's video port addresses in MDOS. Next, was modifying
the KSCAN (Keyscan) routines to use the MDOS KEYBOARD XOP. All keyboard
mapping for the TI-99/4A required modification to pass into variable labels I
added. The next modification and updates required adding memory mapping and
then fragmenting the code around the TIPI interface.

With the TIPI interface, use of the actual code in the TIPI DSR while in MDOS
mode can not be used. Rather, as had been previously learned when developing
code for MDOS to work with the Geneve, the send and receive message routines
needed to be in the MDOS code itself rather than running the code from the
eprom directly. This is not clearly understood why, but is a requirement.

Finally, the most complex section of code needing to be modified was the DSR
routines. With the TI-99/4A, the PABS are written to VDP prior to calling the
DSRLNK code. With the Geneve 9640 in MDOS mode, PABS are in CPU RAM. While
this may not seem all too complex, to accomplish what Stuart needed with the
limited memory of the TI-99/4A, the use of overlapping PABS for several files
he uses in the code required time to convert.

With the browser, Stuart maintains an equivalent character definition in the
FONTS file at TIP1.BROWSER. I have embedded the contents of this file into the
MDOS version as each page update would result in reloading the file as the
browser tags allow character redefinition for various graphics. The COOKIES
file maintains definition credentials for use such as on the myti99.com
website.

The FAVS file maintains a list of favorites accessible from a keyboard keypress
for a webpage you can define. The most complex file was the LINKS file. This
file maintains a list of records on the currently displayed page. As html tags
such as input and submit process, these records for the content contained in
the LINKS file is modified. It was truly an ingenious way of handling complex
code. Stuart deserves a lot of credit for his accomplishment.

Requirements
============

The MDOS version will use a USB TIPI mouse. If a USB TIPI mouse is not
available, then one may use the keyboard. The joystick routines were removed
following the conversion to the MDOS version.
.
On the TIPI, you must have a folder named BROWSER. You can either copy the
program image files to that folder and keep everything contained, or place the
browser files at another location. You will need Stuart's files he distributed
including COOKIES, FAVS, LINKS, and FONTS to be installed in the same folder.
Stuart's original INTERNET file, an EA#3 file, can also be run on the Geneve in
GPL mode using the ROMPAGE.

Future Updates.
==============

I have an idea or two about future updates, however I do not know if Stuart
will continue development of the TI-99/4A version. I am very hesitant to
utilize the higher graphic mode environments of the 9938 video chip on the
Geneve. I say this because this would likely render incompatibilies with the
TI-99/4A webpage displays.

Recognition
===========

Again, I would like to recognize Stuart for his accomplishment and trust to
allow me to convert his program to be used in MDOS mode on the Geneve. While I
believe I created no bugs, thus far, everything tested responds as predicted on
the Geneve. If there is a reproducible issue found where code does not behave
the same between Stuart's release for the TI-99/4A and the MDOS version, please
let me know.

Beery Miller
Beery@USWingNuts.com
9640News on Atariage

2/19/2023