CLSX.C Notes -- M. M. Peritsky 3/28/96

This program is an enhancement to the program CLS.C by James Hall. CLSX now
tests for the presence of ANSI.SYS, and uses the BIOS if ANSI.SYS is not
loaded. It attempts to make reasonable accomodations based on hardware
limitations; eg, the IBM Monochrome Display Adapter doesn't support colors
(obviously!), the IBM Color Graphics Adapter doesn't support underlining, etc.
Also, the BIOS doesn't maintain a "current attribute" in the way that ANSI.SYS
does, so the /s switch is ignored if the BIOS is being used.

CLSX uses some bios.h function calls provided in Power C by Mix Software:

clrscrn - clear the screen
clrscrn2 - ditto, with attribute specified
curscol - get cursor column
cursrow - get cursor row
getvmode - get video mode
setvmode - set video mode

These are all simple interrupt-10h calls, so it should be straightforward to
port the program to another C compiler. Only the first two (clrscrn and 
clrscrn2) are tricky; to clear the screen using int-10h, use the "scroll up"
function, with the AL register set to 0 to scroll the whole screen.

An improvement I'd like to make someday (or someone less lazy than I am can
make it, hint, hint!):
Multiple attributes, so I can say CLSX BLINKING BRIGHT WHITE ON RED.

M.M.P.