MIPS Architecture

What is MIPS Architecture?

The MIPS architecture refers to the microprocessors introduced in 1985 and developed by MIPS Technologies. These processors are designed to be used in embedded systems.

Technically, these specific types of processors use a Reduced Instruction Set Computer or RISC.

There is a specialized version of MIPS processors called the MIPS-X that are also designed to be used in small embedded systems such as DVD players.

Understanding MIPS Architecture

What is MIPS Architecture

MIPS is a particular kind of Microprocessor without Interlocked Pipeline Stages, which is also the full form of it.

Though this is not commonly known among the general public, it is very common in the engineering fields.

Typically, this is a load/store architecture, which is also referred to as a register-register architecture, with the exception of the load/store instructions used to access the memory and all instructions typically function on the registers.

The good thing about the MIPS processor architecture is that a lot of complicated functions are removed.

This, in turn, helps in enhancing the raw processing power of the CPU.

The fundamental idea of developing the MIPS architecture is to increase the operational speed of the Central Processing Unit without it being interrupted by the additional functionalities.

Therefore, it is not surprising that the microprocessors with MIPS architecture have so fast whittled down to the basics.

Several manufacturers of embedded systems realized that these specific types of chips could be used in their systems very easily with very little or no modification required for it.

The MIPS architectures earlier came only in 32-bit version, but, later on, 64-bit versions were also developed.

You will find different versions of it with diverse features and capabilities available, along with a few other optional, application-specific extensions as well.

The different versions of the MIPS architecture are:

There are also a few other Application Specific Extensions available that are based on the MIPS 32 and MIPS 64 architectures and are collectively called the ASEs.

These ASEs come with features that enhance the performance and efficiency of the processors while handling specific types of workloads, such as digital signal processing, for example.

Some of the ASEs are:

MIPS MCU – These ASEs are developed for microcontroller applications with additional support for the interrupt controller. It enhances I/O peripheral control functions and reduces the interrupt latency, two major requirements of a microcontroller system design.

MIPS16 – These ASEs are extensions for MIPS I to V and reduce the size of the application by as much as 40% since they use 16-bit instead of 32-bit instructions.

They also enhance the hit rate of the instruction cache and power efficiency offering a performance that is equivalent to the base architecture.

MIPS Digital Signal Processing (DSP) – These ASEs come with newer instruction sets that help in expediting a wide range of media applications, especially those related to audio and video.

With a state in the integer pipeline, the DSP module needs negligible additional logic for the MIPS processor cores to function.

MIPS SIMD architecture (MSA) – These ASEs also come with several instruction sets and features that accelerate multimedia.

MIPS virtualization – This ASE supports virtualization technology with appropriate hardware.

MIPS multi-threading – This ASE enhances the performance of those applications that need more fine-grained thread processing. Each core in it can support as many as two Virtual Processing Elements or VPEs sharing a single pipeline and other hardware resources.

They also allow allocating processor cycles to the threads and sets the priorities of the relative threads with a discretionary QoS or Quality of Service manager block.

SmartMIPS – This ASE is supported only by MIPS 32 and improves the performance of the processor and at the same time reduces consumption of memory for smart card software.

MIPS Digital Media eXtension (MDMX) – Just as the name implies, this ASE accelerates multimedia applications common in the RISC and CISC systems.

MIPS-3D – This ASE improves the performance of the applications that involve 3D graphics with the additional instructions.

Where is MIPS Used?

Though the MIPS chips were used extensively in the personal desktop computers, workstation, and server computers in the 1980s, these basic RISC systems found a prominent place in the embedded systems later on.

Apart from that, the features of this specific type of architecture and the design of the MIPS chips allow them to be used in the embedded systems that come with small computers built in them.

It helps them to run more sophisticated devices and gadgets such as:

The most significant reason that the MIPS came to an unexpected and sudden halt and moved into the embedded systems is the announcement of Microsoft that their operating system would not support a large range of RISC chips any more.

However, other operating systems continued to support RISC chips, which is why the MIPS migrated to embedded systems.

Is MIPS a Programming Language?

Literally, the term MIPS is an architecture and an acronym for Microprocessor without Interlocked Pipeline Stages but, technically, it also refers to the assembly language of the processor.

However, this language needs a deeper understanding of the operation of the systems at a lower level before creating MIPS assembly language code.

It needs a very good IDE or Integrated Development Environment. This will help in compiling and executing the MIPS assembly language code.

The general structure of a typical program created in MIPS assembly language has two basic parts such as:

Data declaration section:

This is the section where the variables are created and defined that are to be used in the program. This is also the section where storage is assigned to the Random Access Memory or RAM.

The different variables declared by the MIPS assembly language program are:

Code section:

This is where the instructions are written that are to be carried out by the program. The code section has a starting point and an ending point marked with the labels “main” and “exit” system call.

This specific section involves two specific functions, namely the manipulation of registers and the performance of arithmetic operations.

In the manipulation of registers, there are three basic concepts utilized such as:

Performance of arithmetic operations:

There are three operands used in most arithmetic operations in the MIPS assembly language and all of these are registers and their size is a word.

The general format of the arithmetic operations in this language are:

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The most common arithmetic operations in the MIPS assembly language are:

Is MIPS Better Than X86?

Though x86 is a bit more straightforward and offers better register usage, there is nothing to whine about it.

In fact, considering its other features, MIPS is certainly better than x86 in spite of the fact that it is more popular and there are a lot of online resources available.

The main reasons for the MIPS architecture to have a slight edge over the x86 architecture are:

Do Modern Computers Use MIPS?

Yes, modern computers still use MIPS processors, especially in smaller computing devices such as routers, modems and others, apart from the smaller home computing systems.

The proof that the MIPS is still used today is the fact that newer versions of processors based on this specific architecture are being designed and launched.

Several companies still use the MIPS architecture in designing their modern low-cost microcontrollers that are targeted for the consumer products and supercomputers.

What are the Characteristics of MIPS?

The most significant characteristic of the MIPS architecture is its larger number of registers. Also, it is able to deliver higher performance per square millimeter for the IP cores and higher levels of power efficiency for the System on Chip or SoC design.

Some other notable characteristics of the Microprocessor without Interlocked Pipeline Stages architecture are:

All these attributes have helped the MIPS architecture to bring a proper balance between performance and cost making it a reliable choice for the CPU users.

Is MIPS a RISC or CISC?

Typically, the MIPS is a RISC or Reduced Instruction Set Computer processor architecture that supports much simpler and fewer instructions as compared to the CISC counterparts.

Conforming to the RISC architecture, the MIPS architecture is much faster at completing the instruction cycles as compared to the CISC architecture.

The main reason for this is its simpler design and, as said earlier, its fewer instruction sets.

Just as the RISC processors are more efficient these days, the MIPS architecture is also equally efficient, giving it that significant edge over the CISC processors.

Moreover, it is normally accepted that even the most popular CISC processors that are available, such as the Intel Pentium, translate the CISC instructions internally into RISC instructions before they are carried out.

In addition to that, another good reason to say that the MIPS architecture conforms to the RISC processor architecture is that they both characteristically have a load-store architecture design.

This means that there are generally two instructions for accessing the memory. These are:

Apart from that, it also means that the memory cannot be accessed directly by any of the other instructions.

Technically, this signifies that, if there is an instruction given such as “add this byte from memory to register 1,” in the case of a CISC instruction set, it will essentially need two specific instructions of load and store in a load-store architecture.

These two specific types of instructions would be as follows:

Another significant difference between the CISC processor architecture and the RISC processor architecture, and also subsequently the MIPS processor architecture, is that the CISC architecture offers several different addressing modes.

On the contrary, the MIPS processor architecture only allows for a single and simple addressing mode.

In order to spell out an address, you will need to specify both a register as well as a constant.

Ideally, in the RISC and MIPS architectures, you will need four instructions rather than one as well as an additional register, r4.

The same can be done with only a single instruction is typically CISC architecture.

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However, in spite of all these requirements, the internal circuitry of the Reduced Instruction Set Computer processor architecture is much simpler, just as that of the MIPS processor architecture. That is why it can be made very fast.

However, how this can be made is a completely different topic and beyond the scope of this article.

MIPS vs ARM

Conclusion

As you can see from this article, the Microprocessor without Interlocked Pipeline Stages architecture is quite useful in increasing the raw processing power of a CPU.

Add to that, being a simpler architecture, it is quite efficient as compared to the CISC processors, which is why different variants of it are so popular.