ARM is an Advanced RISC Machine,.
It is a RISC not CISC processor. It is basically a LOAD-STORE architecture, where data processing operations are only between registers and does not involve any memory operations.
It is a 32 bit processor and also has variants of 16 bit and 8 bit architecture, so a word is 32 bits, not 16 bits.
It got auto-increment and auto decremented addressing modes to optimize program loops, which is not very common with RISC processors.
It has a very good speed vs power consumption ratio which makes it suitable for embedded system.
It has 3 stages pipe-line: Fetch, Decode and Execute.
7 sounds a lucky number for ARM:
It has 7 operating modes: Supervisor mode; User Mode, System Mode, Fast Interrupt Mode, Interrupt Mode, Undefined mode and abort Mode.
It has 7 interrupts/exceptions, Reset, Undefined, Pre-fetch abort, data abort, software interrupt, FIQ and IRQ, make ARM enter 5 modes, User Mode and System Mode do not need interrupt to enter,
It has 7 addressing modes: immediate mode, index mode, indirect mode, absolute (Direct) mode register mode, displacement mode and Auto-increment/Auto'decrement mode.
No comments:
Post a Comment