NAME
	dbf - convert FFP dual-binary number to FFP format

   SYNOPSIS
	fnum = dbf(exp, mant);

   FUNCTION
	Accepts a dual-binary format (described below) floating point
	number and converts it to an FFP format floating point number.
	The dual-binary format is defined as:

		exp bit  16	= sign (0=>positive, 1=>negative)
		exp bits 15-0	= binary integer representing the base
					  ten (10) exponent
		man		= binary integer mantissa

   INPUTS
	exp - binary integer representing sign and exponent
	mant - binary integer representing the mantissa

   RESULT
	fnum - converted FFP floating point format number

   BUGS
	None