INT 14 - I1541 - INSTALLATION CHECK                                             
	AX = 4000h
Return: AX = 1541h if installed
	    BH = I1541 major version (BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits.  Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.)
	    BL = I1541 minor version (BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits.  Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.)
	    CX = 0000h