@Override
	public Instruction getPrevious() {
		if (block != null && !block.getStartAddress().equals(address)) {
			// Attempt to get previous instruction if block available
			// There is no guarantee that getPrevious will work.
			// This is done to support the method for certain languages:
			// ParallelInstructionLanguageHelper.executesInParallelWithPreviousInstruction
			// Such languages are responsible for keeping parallel instructions
			// within a single disassembly block.
			Address addr = address.previous();
			if (addr != null) {
				Instruction instr = block.findFirstIntersectingInstruction(addr, addr);
				if (instr != null) {
					return instr;
				}
			}
		}
		if (program == null) {
			return null;
		}
		return program.getListing().getInstructionBefore(address);
	}
Return the byte value repeated for all bytes within this instruction or null
if byte values vary.
@return repeated byte value or null if bytes vary
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/util/PseudoInstruction.java