Question

Difference between CPSR and SPSR

Answer 1

SPSR – Saved Program Status Register

All processor modes except system and user mode have an SPSR.Records the pre-exception value of the CPSR.Upon taking an exception, the CPSR is copied to the SPSR of the processor mode the exception is taken to.This is useful because the exception handler is able to restore the CPSR to the value prior to taking the exception, as well as being able to examine the CPSR in general.

CPSR – Current Program Status Register

Current instruction set stateExecution state bits for the Thumb If-Then (IT) instruction (RAZ in the 3DS ARM processors; not capable of executing IT).Current endianness (E bit, bit 9)Current processor mode (bits 0 - 4)Interrupt and asynchronous abort disable bits

Answer 2

Answer:

The main difference between SPSR and CPSR is Saved Program Status Register (SPSR) and Current Program Status Register (CPSR).

Explanation:

Saved Program Status Register (SPSR) An SPSR is present in every processor mode other than system and user mode. records the CPSR's pre-exception value. The CPSR is copied to the SPSR of the processor mode the exception is taken to once it has been taken. This is advantageous because the exception handler can both investigate the CPSR in general and restore the CPSR to the value it had before the exception was raised. Current Program Status Register (CPSR) current condition of the instruction set State bits for the thumb's execution Instruction in if-then (IT) (RAZ in the 3DS ARM processors; not capable of executing IT). present-day endianness (E bit, bit 9) Processor mode at the moment (bits 0 - 4) Disable bits for interrupts and asynchronous aborts.

Hence , The main difference between SPSR and CPSR is Saved Program Status Register (SPSR) and Current Program Status Register (CPSR).

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