ARM stands for Advanced RISC Machine. It is work on reduces instruction set computer.
ARM architecture uses load-store architecture to perform different operations.
It is a 32bit processor, the word length is 32bit. i.e the size of the register is 32bit.
ARM architecture uses a 32-bit address to access memory i.e it can uses 2^32 up to 4GB memory data time.
ARM ARCHITECTURE Diagram
In the above diagram, there are 37 registers in ARM processor 7 special registers are there from out of 37 registers and 30 general-purpose registers.
Special register’s are R15, CPSR, SPSR-FIQ, SPSR-SVC, SPSR-IRQ, SPSR-ABT, SPSR-Und.
In user mode the ARM processor user R0 to R15 and CPSR to perform the user program execution.
The ARM processor operates in 6 different modes, they are:-
- User/System mode
- First inter
- SVC mode
- IRQ mode
- Abort mode
- Undefined mode
Expect the user mode the ARM Processor used of special-purpose register and the linked register to perform a system-related operation that is the other 5mode is used for system purpose.
The R13 and R14 are used as a link register and instruction register. R14 is known as the stack pointer.
CPSR:-
It is a special-purpose register use to store the condition of the ARM processor after the logical and arithmetical operation.
It consists of different to flags:-
| S Sign | Z Zero | C Carry | V Our flow | I interrupt | T Thumb | Pro CPSR mode |
SPSR:-
This Register is used only by the ARM processor when the system-related operation is made.
It is used in privilege made.