private DWARFLineProgramInstruction stepInstr() throws IOException {
		if (state == null) {
			state = new DWARFLineProgramState(defaultIsStatement);
		}

		long instrOffset = reader.getPointerIndex();

		int opcode = reader.readNextUnsignedByte();

		if (opcode == 0) {
			return executeExtended(instrOffset);
		}
		else if (opcode >= opcodeBase) {
			return executeSpecial(instrOffset, opcode);
		}
		else {
			return executeStandard(instrOffset, opcode);
		}
	}
Read the next instruction and executes it

@return 
@throws IOException if an i/o error occurs
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/line/DWARFLineProgramExecutor.java