ARM INTRODUCTION.ppt that hepls to unnderstand arm
- 2. ARM History
- 3. Introduction ARM is a family of instruction set architectures for computer processors based on a reduced instruction set computing (RISC). The ARM core uses a RISC architecture. The ARM processor core is a key component of many successful 32-bit embedded systems. ARM cores are widely used in mobile phones, handheld organizers, and a multitude of every portable consumer devices.
- 4. Introduction RISC is a design aimed at delivering simple but powerful instructions that execute within a single cycle at a high clock speed. The RISC concentrates on reducing the complexity of instructions performed by the hardware because it is easier to provide greater flexibility and intelligence in software rather than hardware. As a result, a RISC design places greater demands on the compiler.
- 5. Introduction In contrast, the traditional complex instruction set computer (CISC) relies more on the hardware for instruction functionality, and consequently the CISC instructions are more complicated.
- 6. RISCDesignPhilosophy The RISC is implemented with four major design rules: Instructions— RISC processors have a reduced number of instruction classes. These classes provide simple operations that can each execute in a single cycle. Each instruction is a fixed length to allow the pipeline Pipelines— The processing of instructions is broken down into smaller units that can be executed in parallel by pipelines.
- 7. RISCDesignPhilosophy Registers— RISC machines have a large general-purpose register set. Any register can contain either data or an address. Load-store architecture — The processor operates on data held in registers. Separate load and store instructions transfer data between the register bank and external memory. Memory accesses are costly, CISC design the data processing operations can act on memory directly. These design rules allow a RISC processor to be simpler, and thus the core can operate at higher clock frequencies.
- 9. ARM DesignPhilosophy There are a number of features that driven the ARM processor design: Reduce power consumption High code density Price sensitive and use low-cost memory devices Reduce the area of the die Hardware debug technology Instruction Set for Embedded Systems Variable cycle execution for certain instructions Inline barrel shifter leading to more complex instructions Thumb 16-bit instruction set Conditional execution Enhanced instructions