Types of Microprocessor Systems
Microprocessors are a critical component of most modern computers. These tiny chips operate at incredibly fast speeds and can process millions of instructions per second. They are also portable and require minimal power, so they can be used in a variety of applications.
CPUs use general-purpose registers to store arbitrary data. These registers are accessed by programmers through 3-operand instructions. Doubling the number of programmer-visible registers requires more bits to select them, and increases the size of each instruction.
CMOS 65816
The CMOS 65816 is an enhanced microprocessor from the Western Design Center (WDC) which was used by the Apple IIGS and later, in modified form, the Super Nintendo Entertainment System. It is a CMOS enhancement of the venerable 6502 NMOS MPU and offers many features over its forerunner. In addition to the standard CMOS instructions the 65816 adds a number of new features that are not available on the 6502.
The most important new feature is the ability to change register sizes with two instructions. This allows the accumulator to be either 8 or 16 bits while the XY index registers may be eight or sixteen bit wide. This makes a significant difference in performance as it eliminates the need to resort to zero page addressing.
Several other enhancements include an improved interrupt handler. The BRK flag is now handled by the hardware vector instead of being set and cleared via an IRQ. A new phx instruction pushes the program bank register byte onto stack and a plx instruction pulls a byte off the stack into the data bank register.
Another new instruction, stz, stores a zero byte to the destination address. This is a useful alternative to the JMP long instruction. It is also possible to use it in place of an absolute indirect long jump.
RISC
RISC is an instruction set architecture that aims to improve CPU performance by reducing the number of instructions required to perform a task. It also AC converter reduces the time it takes for those instructions to execute by implementing a pipelining technique. Its simpler instructions also allow for more memory registers to be used, reducing the need for repeated instructions to access data in memory. This means that a RISC processor can complete most commands in one machine cycle.
Unlike traditional CISC CPUs, RISC processors have smaller sets of simplified instructions and do away with microcode altogether. This enables them to run faster, and can even execute multiple instructions simultaneously using a process called pipelining. This is especially useful for executing complex instructions that require a lot of steps to complete.
Additionally, RISC processors have larger registers and support more complex addressing modes than their CISC counterparts, which can result in more efficient use of memory. This can be beneficial for battery operated devices where power usage is an important consideration. RISC processors also have simpler instruction decoding logic, which can make them more efficient.
As a result of these advantages, RISC processors have become an increasingly common choice for manufacturers. They can be found in a variety of devices, from laptops to desktop computers. The world’s fastest supercomputer, Summit, runs on a RISC-based processor.
CISC
CISC is an acronym for Complex Instruction Set Computer, and is a type of microprocessor architecture that makes use of general purpose hardware to carry out commands. CISC chips are simple to program and make efficient use of memory. In contrast, RISC microprocessors are more complex to program and require more memory to store instructions. However, CISC processors are less expensive and have better performance than RISC processors.
The CISC microprocessor architecture has a wide range of commands, including the ability to manipulate operands directly within memory. This allows for the execution of intricate tasks with a single command, which reduces the number of instructions required and reduces the risk of errors. This feature is also useful when addressing multiple data types. CISC processors also support a variety of addressing modes to increase flexibility.
CISC processors are designed to perform a smaller number of types of computer instructions, which means that they can operate at higher speeds. They can also execute instructions in a shorter time than RISC processors, which can save time and money. In addition, they have a fixed length of instructions and simple addressing modes. They can also access the memory using a LOAD and STORE instruction, which eliminates the need to translate high-level programs or statements into machine code. However, CISC processors can take longer to process complex and interdependent instructions than RISC processors.
ARM
The ARM processor architecture is one of the most popular for mobile devices and is used in many different types of embedded systems. It is based on an instruction set known as reduced instruction set computing (RISC). Compared to CISC computers, Delay Lines component the ARM architecture uses smaller transistors. This means that it can deliver faster performance with less power. ARM chips are also designed to support multiprocessing, which allows them to run multiple applications simultaneously.
ARM also offers a non-intrusive method of extending its instruction set by using coprocessors. These coprocessors have their own state and execute a subset of the ARM instruction set. For example, the ARM7TDMI processor uses a Thumb instruction set to reduce its memory footprint. This feature is especially useful in high-density applications.
In addition to supporting multiprocessing, ARM chips offer a number of other features that make them suitable for use in IoT and other embedded systems. For example, the Cortex-M series includes a digital signal processor (DSP) that can respond to and manage analog signals for applications such as voice recognition or sound synthesis.
Another benefit of ARM is that it can help streamline the process of validating, verifying and certifying safety-critical software. This can save time and money by allowing developers to validate, verify and certify code in the context of their actual hardware.