@Override
	public RegisterValue getRegisterValue(Register register) {
		Varnode regVnode = trans.getVarnode(register);
		Varnode value = this.getValue(regVnode, false, null);
		if (isConstant(value)) {
			return new RegisterValue(register, BigInteger.valueOf(value.getOffset()));
		}
		return null;
	}
Extend a constant value if it can be extended.

@param out varnode to extend into (for size)
@param in varnode value to extend the size
@return new sign extended varnode
Ghidra/Features/Base/src/main/java/ghidra/program/util/VarnodeContext.java