According to the Korean publication ET News, Samsung is in the process of designing their own processor, which will use a customized version of the standard ARM architecture, similar to Qualcomm's Snapdragon processors.
You're probably thinking, “but Samsung already makes its own processors,” and you're not wrong. Here's the thing. All the ARM-based processors use the ARM architecture provided by ARM (a British company), but companies like Apple and Qualcomm obtain an “architecture license” and take the default ARM design and tweak it to create versions of their own (users of dedicated GPUs on PCs can relate this to how companies like ASUS and XFX make custom versions of NVIDIA's GeForce cards, increasing clock speeds, component arrangement, and the like).
This has advantages, such as being able to get higher performance, better power efficiency, and basically improve on the reference design. As a company that has been making processors that have constantly beaten other processors in performance, Samsung is no doubt looking to take it one step further by going with a customized ARM architecture, as powerful competition like Qualcomm's Snapdragon 800 and (to some extent) the NVIDIA Tegra 4 emerges in the coming months.
We'll be waiting with bated breath to see what Samsung is able to do, though we'll have to wait till the first/second half of 2014 to see products using the new processor (the Galaxy S5 will likely use it), according to an anonymous employee quoted by ET News.