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Hi,
When I read about Thumb2 instructions, I have such a question: How many states for a Coretx A8? I know it has ARM and Thumb states. Thumb2 instruction is belong to Thumb state? Then does A8 have a pure Thumb instruction besides Thumb2 set?
Thanks,
It really depends on what you mean by states! One could say that anything described in the program status register is a state
Cortex-A8 Technical Reference Manual: 2.14. The program status registers
As far as instruction sets are concerned ARM mode and Thumb-2 mode are the major ones. ThumbEE is a variant of Thumb for implementing languages like Java more easily but it is being phased out, and Jazelle had support for Java byte codes but that has been abandoned and just has a trivial implementation in Cortex A8.
Thumb-2 is an extension of Thumb instruction set, it is not a separate state. A couple of tweaks were made in Thumb-2 to fix problems in Thumb but you can't get a version of Thumb without the Thumb-2 extensions on Cortex A8.