H E R C U L E S
---------------

This .ARC file contains two sets of information:


- HERCULES.PRG is a memo from Bob Morse and a note from me
explaining the programming parameters for the Hercules (and
clone) graphics board. His information is especially useful
because he lists the internal parameters which must be
programmed into the 6845 chip to get graphics mode to work
correctly. Please report any problems with this information to
me at DECWET::BROWN or Bob at LEWS2::MORSE.

HERCDEMO.COM (source included as HERCDEMO.ASM) is a quick and
dirty demo program I wrote to help me understand the way the
HERCULES card works, and use graphics character generation.


- HERCBIOS.COM plus support sofware. HERCBIOS.COM is a terminate-
and-stay-resident program which takes over some functions from
ROM BIOS INT 10h, providing IBM-compatible graphics modes 6 (640
by 200) and 7 (monochrome text) and adding mode 8: Hercules
graphics (720 by 348). Other functions are just passed through
to the existing ROM BIOS.

HERCBIOS was written by Dave Tutelman at AT&T in New Jersey, and
the software came to me via net.micro.pc, hot off the wire two
days ago. I've included his note and banner as HERCBIOS.AUT.

HERCBIOS.DOC explains the operation of the program in detail.

HCHARSET.ASM is a simple test program to demonstate IBM and
HERCULES modes.

There is also a C program which gives a more extended demo of
the facility: TESTPIX.C. TESTPIX must be linked with another C
module, HERCPIXL, which provides the actual linkages to INT 10h.
Since system calls are implementation specific, there are two
versions of this module: HERCPIXL.DC and HERCPIXL.LC.
HERCPIXL.DC is DeSmet C compatible and HERCPIXL.LC is Lattice C
compatible. I've included TESTPIX.EXE (build with Lattice) so
you can test the software if you don't have C.

Finally, there are two make files: HERCMAKE.ATT and
HERCMAKE.LCM. HERCMAKE.ATT is a make file for a make program
which looks UNIX compatible, so I called it ".ATT".
HERCMAKE.LCM is a make file for the Larry Campbell MAKE program
I use. In either case, you will have to use the -f switch
invocation of MAKE. E.g: MAKE -f HERCMAKE.LCM HERCBIOS.COM.

HERCBIOS.COM seems to work quite nicely as advertised, but I
must warn you that there are some functions which are not yet
implemented -- scrolling in graphics mode, for one. I'm sure
Dave will continue to enhance it and hope to get future updates.
In the meantime, if anyone gets brave and tackles scrolling, put
the updates on PAR5!


-Reid Brown
6-Sep-1986
DECWET::BROWN