hi, expert
i study ArmV8 architecture.
On taking an exception to a higher Exception level, the Execution state either:
• Remains unchanged.
• Changes from AArch32 state to AArch64 state.
i konw that When an higher exception occurs, the execute state is changed from A32 to A64 state.
I wonder Remains unchanged and changed(from AArch32 state to AArch64) state conditions.
In ARMv7, Arm or Thum bit changes 16 bit/ 32 bit, in ARMv8 is there same decision bit?
> I wonder Remains unchanged and changed(from AArch32 state to AArch64) state conditions.
The state which is switch to / restored follows the same semantics as ARMv7 - the program status registers carry all of the state.
> In ARMv7, Arm or Thum bit changes 16 bit/ 32 bit, in ARMv8 is there same decision bit?
No; there is no equivalent on Thumb in the 64-bit ARMv8; there is a single 32-bit fixed width instruction set.