private BigInteger extractFractionalCode(BigInteger x) {
		BigInteger mask = BigInteger.ONE.shiftLeft(frac_size).subtract(BigInteger.ONE);
		return x.shiftRight(frac_pos).and(mask);
	}
Get the minimum finite subnormal {@link BigFloat} value for this format

@return minimum finite subnormal {@link BigFloat} value
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcode/floatformat/FloatFormat.java