public static BigFloat infinity(int fracbits, int expbits, int sign) {
		return new BigFloat(fracbits, expbits, FloatKind.INFINITE, sign,
			BigInteger.ONE.shiftLeft(fracbits - 1), (1 << (expbits - 1)) - 1);
	}
@param fracbits number of fractional bits
@param expbits number of bits in the exponent
@param sign +1 or -1
@return +inf or -inf
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcode/floatformat/BigFloat.java