ARM architecture analysis

In the mid-1980s, a small team at Acorn needed to select a suitable processor for their next-generation computer. According to the technical requirements they provided, they could not find a suitable processor on the market at that time, so Acorn decided to design a processor themselves (really bold). A small team completed the entire process from design to implementation in just 18 months. This is a computer with a RISC instruction set, called Acorn RISC Machine (ARM for short). Later, Acorn declined, and the processor design department was separated to form a new company.

ARM mainly designs ARM series AISC processor cores. It does not produce chips, but only provides IP cores. Let's first explain the architecture, core, processor and chip with an example: S3C2440, which is a SoC chip. Note that it is not a CPU. 2440 is somewhat similar to the 51 microcontroller we are familiar with. Both are embedded. The development of embedded has gone through three stages, namely SCM, MCU, and SoC. 51 belongs to SCM or MCU, while 2440 belongs to SoC. Let's first look at the internal structure of the 51 microcontroller.

Its internal structure can be simply divided into two parts: CPU and peripherals. Let's look at 2440:

 

The arm920t in the middle is its processor. In my opinion, processor and core are the same concept here, but one is a hard concept and the other is a soft concept. The 920t here is both a processor and a core. What Samsung does is other things besides this CPU.

 What about the architecture? Let's look at another picture.


The left side is the architecture, and the right side is the processor, also called the core. ARM's first and most successful CPU is ARM7TDMI, which is based on ARMv4. The ARM architecture includes the following RISC features:

ARM naming convention: