I doubt OS X contains much if any code that Apple doesn't have the source to. This isn't so much speculation as common sense.
Apple as a company is the very embodiment of control. Ever since Jobs took the reigns back they have held the entire production pipeline of their products in an iron grip. I wouldn't imagine software, especially driver code that has such a massive impact on user experience to be any different.
GPU vendors allow game engine developers of a reasonable size access to the source of their drivers, why do you think that a company much more powerful (and actually a customer) would be denied the same access?
The implication they probably (re)wrote most if it themselves wouldn't surprise me much either. They have already shown that low level engineering is neither beneath them or beyond their capability. They produced their own ARM chips well ahead of the other vendors (even beating out veterans in that space like Qualcomm) and have continued to show they want to control everything except maybe the fab.
So lets be honest, the only thing that is likely to be true is they have access to everything and probably influence development of PowerVR hardware significantly.
Apple as a company is the very embodiment of control. Ever since Jobs took the reigns back they have held the entire production pipeline of their products in an iron grip. I wouldn't imagine software, especially driver code that has such a massive impact on user experience to be any different.
GPU vendors allow game engine developers of a reasonable size access to the source of their drivers, why do you think that a company much more powerful (and actually a customer) would be denied the same access?
The implication they probably (re)wrote most if it themselves wouldn't surprise me much either. They have already shown that low level engineering is neither beneath them or beyond their capability. They produced their own ARM chips well ahead of the other vendors (even beating out veterans in that space like Qualcomm) and have continued to show they want to control everything except maybe the fab.
So lets be honest, the only thing that is likely to be true is they have access to everything and probably influence development of PowerVR hardware significantly.