private long getInstructionBytes(ParserWalker walker) throws MemoryAccessException {
		long res = 0;
		long tmp;
		int size, tmpsize;
		int bs = bytestart;

		size = byteend - bytestart + 1;
		tmpsize = size;
		while (tmpsize >= 4) {
			tmp = walker.getInstructionBytes(bs, 4);
			res = res << 32;
			res |= (tmp & 0xffffffffl);
			bs += 4;
			tmpsize -= 4;
		}
		if (tmpsize > 0) {
			tmp = walker.getInstructionBytes(bs, tmpsize);
			res = res << (8 * tmpsize);
			res |= (tmp & 0xffffffffl);
		}
		if (!bigendian) {
			res = byteSwap(res, size);
		}
		return res;
	}
Build a long from the instruction bytes at the current point in the parse
@param walker is the instruction parse state
@return the recovered value
@throws MemoryAccessException for problems reading the bytes
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/processors/sleigh/expression/TokenField.java