What is meant by Cpsr?

The Current Program Status Register (CPSR) holds processor status and control information. More…

What is Cpsr and Spsr in ARM?

The SPSR is used to store the current value of the CPSR when an exception is taken so that it can be restored after handling the exception. Each exception handling mode can access its own SPSR. User mode and System mode do not have an SPSR because they are not exception handling modes.

What is the use of Cpsr register in ARM register bank?

Current Program Status Register The ARM core uses the cpsr to monitor and control internal operations. The cpsr is a dedicated 32-bit register and resides in the register file. Figure 2.3 shows the basic layout of a generic program status register.

Which is the current program status register ( CPSR )?

Current Program Status Register (CPSR)¶. The status register bits. N. Is set to bit 31 of the result of the instruction. If this result is regarded as a two’s complement signed integer, then N = 1. If the result is negative and N = 0 if it is positive or zero.

What are the status registers in an ARM processor?

Current Program Status Registers in Traditional ARM Processors. Status registers are used to test for various conditions in an operation, such as ‘is the result negative’, ‘is the result zero’, and so on. The two status registers have 16 bits and are called the instruction pointer (IP) and the flag register (F):

How does the ARM instruction set control a PSR?

The ARM instruction set provides two instructions to directly control a program status register (psr ). The MRS instruction transfers the contents of either the cpsr or spsr into a register; in the reverse direction, the MSR instruction transfers the contents of a register into the cpsr or spsr.

What are the four bits of the CPSR?

ARM v6/v7 maintains a status register called the CPSR (current program status register) that holds four status bits, negative (N), zero (Z), carry (C), and overflow (O). These bits can be used for conditional execution of subsequent instructions.