MIPS X-Ray: A plug-in to MARS simulator for datapath visualization

This paper presents the design and implementation of a Microprocessor without Interlocked Pipeline Stages (MIPS) pipelined simulator build on top of the MIPS Assembler and Runtime Simulator (MARS) as a plug-in. The MARS Simulator is a lightweight interactive development environment (IDE) for programming in MIPS assembly language, intended for education-level use. This plug-in called "Pipelined Simulator and Branch Explainer (PBSE)" provides the MARS users with the ability to simulate a pipelined processor execution of MIPS assembly instruction which the original MARS simulator does not support. The tool also provides additional functionality as such Branch Prediction. With the use of the plug-in, MARS users can better analyze the assembly codes executed in a pipelined processor with branch prediction and improve their understanding of Computer Architecture.

This paper presents the design and implementation of a pipelined 9-bit RISC Processor. The various blocks include the Fetch, Decode, Execute and Store result to implement 4 stage pipelining. Harvard Architecture is used which has distinct program memory space and data memory space. The only load and store is used to communicate with data memory. RISC using pipeline makes CPI as 1 and improves speed of execution. Verilog Language is used for coding purpose. The proposed architecture is then simulated using Modelsim. Reduced Instruction Set Computers (RISCs) are now use for all type of computational tasks. In the area of scientific computing, RISC workstations are being increasingly used for compute task such as DSP, DIP etc. RISC concepts help to achieve given levels of performance at significantly lower cost than other systems. Pipelined RISC improves speed and cost effectiveness over the ease of hardware description language programming and conservation of memory and RISC based designs will continue to grow in speed and ability. The main features of RISC processor are the instruction set can be hardwired to speed instruction execution. In the present work, the design of a 4-bit data width Reduced Instruction Set Computer (RISC) processor is presented. It has a complete instruction set, program and data memories, general purpose registers and a simple Arithmetical Logical Unit (ALU) for basic operations. In this design, most instructions are of uniform length and similar structure, arithmetic operations are restricted to CPU registers and only separate load and store instructions access memory. The architecture supports 8 instructions to support Arithmetic, Logical, Shifting, and load -store operations. Verilog HDL has evolved as a standard hardware description language. A hardware descriptive language is a language used to describe a digital system. HDL's allows the design to be simulated earlier in the design cycle in order to correct errors or experiment with different architectures. Designs described in HDL are technology- independent, easy to design and debug, and are usually more readable than schematics, particularly for large circuits. More recently Verilog is used as an input for synthesis programs which will generate a gate-level description for the circuit. The simulator which is used for the language is Xilinx ISE and Modelsim. Verilog is capable of describing simple behaviour. Machine cycle instructions allow the processor to handle several instructions at the same time. The processor can work at a high clock frequency and thus yields higher speed. This paper is about design of a simple RISC processor and synthesizing it. The RISC architecture follows single-cycle instruction execution.

Chapter 6 - MIPS Exception Handling

Research motivation. When developing microcontrollers, manufacturers try to include as many different types of peripherals as possible in order to increase the marketing attractiveness of their products. On the one hand, with a large assortment of various peripheral modules, it is very difficult to implement several devices of the same type in the microcontroller: manufacturers are mainly limited to 1-2 instances, in rare cases 4 modules of the same type are included. On the other hand, most software projects do not use all the peripherals of modern microcontrollers and many devices are left unused, while there may be a shortage of other types of modules. Another problem that has become especially noticeable for microcontrollers used in the field of IoT is the cryptographic protection of data that is transmitted through built-in information exchange interfaces. The main efforts of researchers and developers of cryptographic data protection methods were aimed at reducing energy-intensive operations, memory access iterations and speeding up encryption processes while maintaining a high level of cryptographic protection and enabling efficient data distribution within IoT devices networks. Research results. This paper presents an alternative approach to the manufacture of peripheral modules as part of microcontrollers. The authors propose to use a configurable software processor module based on the MIPS architecture with a reduced instruction set and limited capabilities. Conclusions. This approach would make it possible to dynamically change the functionality of peripheral modules in accordance with the requirements of the developed software solution, which in turn will increase the efficiency of the microcontroller chips capabilities utilization. In addition, the transfer of data stream encryption functions to the reconfigurable core of the peripheral module will provide fast and transparent cryptographic protection, as well as allow offloading the microcontroller core and increasing the energy efficiency of chips while reducing their production cost.

Reduced Instruction Set Computing (RISC) processors have wide selection of applications performance on speed and better cache memory. The advanced RISC microprocessors are extensively used for many of the complicated systems. Reduced Instruction set Computing (RISC) is a CPU (Central Processing Unit) design mechanism that displays fundamental instruction set and performs better after comparison with the other microprocessor architecture and has the ability to perform commands per instruction through microprocessor cycles. The proposed processor is designed using Harvard architecture, having separate instruction and data memory. Building of a fully synthesizable 32-bit RISC processor with Fetching unit, Decoding unit, Data and instruction memory, and Execution unit. The RISC Processor design is synthesized and implemented using Xilinx ISE Tool and simulated using I-sim. A 32-bit RISC is simulated and checked through VIO IP cores. We can use debug feature to drive and monitor signals that are present on the real hardware. This work is intended with Verilog HDL and implemented with the help of development board using Artix-7 FPGA device. The outcomes of performance are evaluated in terms of area, timing performance and maximum frequency of operation. The RISC processor compares earlier comparable architecture with efficient developments.

Register array processor

Omega - A RISC Architecture for Real-Time Applications

The evolution of computer architecture has given rise to two main approaches: RISC (Reduced Instruction Set Computer) and CISC (Complex Instruction Set Computer). These architectures differ significantly in terms of instruction design, efficiency, and performance. This study aims to analyze the performance and efficiency of RISC and CISC in the context of computer architecture organization. The methodology includes a literature review, comparative analysis, and performance evaluation based on parameters such as processing speed, power consumption, and design complexity. The results indicate that RISC tends to be more efficient in terms of power consumption and execution speed for simple instructions, while CISC excels in handling complex instructions with fewer lines of code. The findings of this study can serve as a reference for the development of modern computer architectures that balance performance and efficiency.

To the present day, the performance of microprocessors has progressed dramatically. Recently, almost all computer systems use reduced instruction set computer (RISC) architectures. However, about 30 years ago, complex instruction set computer (CISC) architectures were widely used for almost all computer systems. The advantages and successes of RISC architectures are attributable to their simplified structures. Conventional complex instruction set computer (CISC) architectures invariably included various and numerous instruction sets. Each instruction was able to execute a complicated multi-step operation. For that reason, the CISC architectures were useful in assembler-based programming environments and in systems with small amounts of memory. However, such complicated architectures prevent increases in clock frequency or a processor’s processing power. Therefore, RISC architectures—which use simple architectures based on single-step instruction sets—have been developed. The RISC architectures present advantages in terms of higher clock frequency, smaller implementation area, and lower power consumption than conventional complex instruction set computer (CISC) architectures. Observation of many examples reveals that, in circuit implementations, a simple structure is best to increase the overall performance. That principle is also applicable to programmable devices. If clock-by-clock reconfigurable devices are used, even a single instruction set computer (SISC) can be implemented onto them. A single instruction set computer is one in which a processor has only a single instruction. During production, various single instruction set computers are prepared: a single instruction set computer with an AND logic function, a single instruction set computer with an adder function, and so on. These processor units are implemented at necessary times and at necessary places of a programmable device. In CISC and RISC architectures, the hardware is fixed. Its operations are switched using software commands, as portrayed in Fig. 1(a). In contrast, in a single instruction set computer, the operation changes are executed by hardware reconfigurations, as shown in Figs. 1(b) and 1(c). Therefore, in a single instruction set computer, a processor with a certain function itself can be reconfigured to another processor with another function. The implementation of such single instruction set computers provides the following advantages under programmable device implementations. A single instruction set computer with the simplest architecture can operate at the highest clock frequency among all processor architectures. In RISC architectures, many selectors to change functions are implemented; such selectors have a certain delay. However, single instruction set computers

A comparison of conventional single-chip on high-density printed wiring board (PWB) packaging with both ceramic and silicon-substrate multichip module (MCM) strategies is presented. Both approaches are assessed given current state-of-the-art manufacturing capabilities and projections for the foreseeable future. The computer system used as the basis to investigate the relative impact of these packaging approaches is representative of a current workstation with a reduced instruction set computing (RISC) architecture. This study was conducted with AUDiT Version 4.2, an innovative simulation tool for evaluating the physical design of electronic systems. It is demonstrated that the maximum efficiency of the conventional single-chip PGA module on PWB packaging of state-of-the-art RISC workstations, such as the IBM RS/6000, is only about 14%. The addition of signal layers may improve speed performance for a given PWB design rule, but not beyond the PGA package tiling limit constraint. Introduction of multichip packaging greatly increases processor speed and dramatically reduces the overall system size. >

This paper presents the design of multi-cycle 32-bit Reduced Instruction Set Computer (RISC) processor for better performance and higher speed of operation. The processor is capable of executing more number of instructions with simple design and less critical path delay. The designed processor was simulated and synthesized using Xilinx 14.7 ISE design suite. The processor executes each and every instruction in more than one cycle that's why the term multi-cycle. Each instruction is divided into three main states namely the Fetch state, the Decode state and the Execution state. The first two sates remain the same for all the instruction the last state, however depends on the type of operation performed in that instruction.

Hardware software co-design plays a crucial part in the embedded processor development especially with the current advancement of reconfigurable platforms. The reconfigurability features offered by platforms such as Field Programmable Gate Array (FPGA) has permitted the modification of the internal processor architecture with lower cost and higher performance. While the hardware architecture could be changed through various methods, the modifications need to be complemented with a compatible assembler that suits the amended architecture. This paper presents a two-pass assembler design technique that adapts to any instruction set architecture (ISA) modifications being applied on a reconfigurable processor. A Reduced Instruction Set Computer (RISC) processor core, which is described in Verilog Hardware Description Language (HDL), is used as the testing platform whereby its ISA is expanded to include new instruction sets. The assembler is developed based on two-pass approach and the assembling process would generate a coefficient file that is used as initialization files during the FPGA implementation of the processor core. The assemblers have been successfully developed with correct output format and verified during the FPGA implementation using Xilinx Spartan-3AN board.

The embedded systems have received increasing research interest in recent years due to its wide usage. This paper presents system on programmable chip (SOPC), a new technology in the embedded systems, to support the development of design projects for undergraduate students in their electrical and computer engineering curriculum. FPGA-based SOPC development board with reduced instruction set computer (RISC) processor cores, a top-down design approach with FPGA computer-aided design tools, a C compiler for the RISC soft-processor core and a large FPGA with on-chip memory are used for a wide variety of student design projects. The course, which includes both software and hardware, can meet the different needs of students from different professional backgrounds and contribute to a better understanding between electrical engineering and computer science and therefore can increase the competitiveness of students.

At the Fox Chase Cancer Center a Hospital Information System (HIS) has been developed which presents images from CT and MRI along with other patient information at more than 75 locations in the hospital. X-terminals are used to display these images along with text and plots of other clinical data, such as radiology and pathology reports, progress notes, clinical laboratory results, and patient orders. The X-terminals are located in the clinic, at nursing stations, physician offices, and in radiology. The HIS is implemented on a distributed client-server local area network (LAN) of Reduced Instruction Set Computer (RISC) workstations. The CT and MRI scanners, as well as the film printers, are also configured as network nodes. Whenever possible, nonproprietary software and hardware standards are used (e.g., Unix operating system, “C” programming language, OSF Motif X-Windows toolkit, ACR-NEMA image protocol). In the Picture Archiving and Communication System (PACS) developed at Fox Chase, image data is transferred from the scanners to image management RISC workstations where radiology technicians perform image modifications (e.g., window and level setting, zoom). The workstation image data is then queued over the network to the film printers. Images are also archived (using digital audio tape) at the image management workstations. The images can be displayed on the many X-terminals on the LAN, located throughout the institution. Physicians can review the CT and MRI images at the X-terminals while simultaneously accessing additional relevant clinical information. Additionally, radiologists in the reading area can view images at remote X-terminals while a patient is still being scanned, and thereby communicate any needed study modifications to the technicians. We will present the details of our system’s design and implementation, and the experiences of the past two years during which it has been in daily use by our medical staff.

This research paper presents design & simulation of a high performance five stage pipelined 8 bit or 16-bit Microprocessor without Interlocked Pipeline Stages (MIPS), which is a Reduced Instruction Set Computing (RISC) architecture based processor. The purpose of RISC microprocessor is to execute a minuscule batch of instructions, with the intention of proliferating the celerity of the processor. This processor was designed with 5 phases of pipeline in particular Instruction Fetch (IF), Instruction Decode & Register Fetch (ID), Execution & Address Calculation (EX), Memory Access (MEM) and Write Back (WB) modules. The designing process was done using a myriad of modules which are the ALU, Control Unit, Program Counter, MUX, Instruction Memory, Data Memory, CPU, Register File, and Sign Extension. The Proposed design is developed by Verilog HDL and Simulated by Modelsim 6.4 c and Synthesized by Xilinx tool and proposed system implemented in FPGA Spartan 3 XC3S 200 TQ-144.