I have watched you polluting various newsgroups with your infantile garbage.
I'll tell you this in the hope you will go away and learn to do something
worthwhile and cease spewing your anti-other_than_FM crap.

FM on the SB cards was implemented by using the Yamaha OPL2 and OPL3 chips.
The drivers merely wrote various values to the chips to achieve their
sounds.
To program an FM driver therefore, you will need a copy of the manual for
the relevant Yamaha chip plus a copy of this book:
"FM Theory and Applications by Musicians for Musicians". author Dr John
Chowning and David Bristow.
This is the classic work on FM by its inventor Dr Chowning.
As you may or may not know, Dr Chowning licensed his FM tech to Yamaha,
which is why Yamaha had the monopoly on FM-style synthesis for a long time
(which didn't stop imitators such as Casio).

If you had ever heard an SB16, you would know the Yamaha OPL chips don't do
any anti-aliasing, and thus higher frequencies sound terrible. The SB cards
get away with this to a certain extent by implementing rather severe high
and low-pass filters, giving rise to the classic SB sound G
If you intend to program your own FM soft synth, you will thus need to learn
about anti-aliasing.

Despite your strident assertions, FM does not and never did rule.
For a short period, owing to the ascendancy of the DX7 it was in the
limelight. But it was always meant to be a low-cost method of generating
sounds, which fit the 80's perfectly.
FM is best at generating new sounds, and rather hopeless at imitating real
world sounds, with the exception of bells.
FM is also rather good at deep growly basses, especially when layered.
But there are numerous spectrums of sounds for which FM is totally
inadequate at expressing.

FWIW, I still have my original SB 16 ASP ISA card with Waveblaster add-on,
and I _always_ preferred the sound of the WaveBlaster to that of the tinny
FM sounds in the SB16.
Although I don't have a DX7, I have several Yammie synths, a DX11 and YS200.
Unlike the SoundBlasters, these synths were FM done right. No (or minimal)
aliasing and very quiet ( very low noise floor ).

HTH