When are A32 state and A64 state determined?

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?

Parents
  • On system start, execution begins at the highest allowed exception level (often EL3 with AArch64 execution state). When switching down to a lower exception level using an exception return, the code at the higher level sets the desired execution state - this is where the choice happens. When taking an exception back to the higher level, the execution state of the higher level is restored.

Reply
  • On system start, execution begins at the highest allowed exception level (often EL3 with AArch64 execution state). When switching down to a lower exception level using an exception return, the code at the higher level sets the desired execution state - this is where the choice happens. When taking an exception back to the higher level, the execution state of the higher level is restored.

Children
No data
More questions in this forum