public boolean isZero() {
		if (!isFullMask()) {
			return false;
		}
		for (byte val : vals) {
			if (val != 0) {
				return false;
			}
		}
		return true;
	}
Check if all bits are 0 bits

@return true if all are 0, false otherwise
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/sem/AssemblyPatternBlock.java