In fact, the term CPU used for these devices is actually a powerful ARM microcontroller (not a computer-like CPU), which has many capabilities despite its small size. These microcontrollers with their 2-bit processor are far more powerful than 2-bit AVR processors and therefore, they can act as a powerful CPU for gadgets like tablets, advanced mobile phones and more. The ARM series microcontrollers are a prototype of their previous generation, the AVR.
For AVR programming such as Bascom, Codevision, Aver Studio etc … IAR Embedded Workbench for ARM software is one of the best coding, compiling, and debugging ARM microcontrollers available.
