void setValueAt(Instruction instr, BigInteger newValue, boolean valueAssumed) {
		if (instr == null || newValue == null) {
			throw new IllegalArgumentException("instr and newValue required");
		}
		setAddr = valueAssumed ? instr.getMinAddress() : instr.getFallThrough();
		if (setAddr != null) {
			value = newValue;
			if (mask != null) {
				value = value.and(mask);
			}
		}
	}
Set the point at which the register value has changed.
If the previous value setting should be saved, the writeValue
method should be invoked first.
@param instr set instruction or first instruction of range.
@param newValue register value
@param valueAssumed if false the value set point will be at the fall-through
address of the current instruction (normal set operation), if true the value
assumed at the start of the specified instr.  If false and instr does not
have a fall-through, this method has not affect.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/analysis/RegisterContextBuilder.java