protected static long signExtend(long val, int bits) {
		int slam = 64 - bits;
		return (val << slam) >> slam;
	}
Sign extend a number of the given size in bits, to a full long

@param val the value to extend
@param bits the number of bits to take (right-to-left)
@return the sign-extended value as a long
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/expr/MaskedLong.java