Instruction Set Architecture 1 CHAPTER 2 01 16 19 Topics for Discussion 2 Review of Chapter 1 introduction What is computer organization What will you learn in this course Motherboard CPU microprocessor Memory Instruction set architecture Stored program computer Interface between software and hardware Instructions Design principles Instructions registers and memory Simple instructions types and formats 01 16 19 Computer Organization 3 Is the study of major components of a modern digital computer their organization and assembly and the architecture and inner workings of these components It also deals with design principles for a good performance 01 16 19 What will you learn in this course 4 How are high level language HLL translated to the language of the hardware How does hardware execute instructions What is the interface between hardware and software How does the software instruct or control the hardware to perform the needed function What determines the performance of a program How can a program improve performance Original program its translation effectiveness of the hardware other special techniques such as pipelining What techniques can by hardware designers to improve performance 01 16 19 Mother Board 5 Figure 1 10 Contains packages of integrated circuit chips IC chips including a processor cache several memory DRAM connections for IO devices networks disks 01 16 19 Central Processing Unit CPU 6 See Fig 1 9 Example Intel 80386 80486 Pentium Main components of a CPU are datapath and control unit Datapath is the component of the processor that performs arithmetic operations Control is the component of the processor that commands the datapath memory IO device according to instruction of the program Cache provides but fast memory that acts as a buffer for slower larger memory outside the chip 01 16 19 IC chip manufacturing process 7 Lets discuss Fig 1 14 and 1 15 Silicon is a semiconductor by adding appropriate elements it can be turned into a conductor insulator or can be made to switch between the two 01 16 19 Instruction set Architecture 8 An important abstraction between hardware and software Lets discuss this concept Computer operation is historically called an instruction Instructions stored similar to data in a memory give rise to an important foundational concept called the stored program computer 01 16 19 C to MIPS instruction 9 Design principle 1 simplicity favors regularity In the above example all instructions have 3 operands 01 16 19 Register set 10 Where do the data get stored in the CPU Named locations called registers How many Typical small compared to memory sizes Registers MIPS 32 has 32 register Denoted by s0 s1 etc s0 s5 Temporary registers are denoted by t0 t1 01 16 19 C to MIPS instruction Take 2 with registers 11 Design principle 2 Smaller is faster Memory available as registers is 32 in number 01 16 19 Memory Operations 12 Data and instructions are stored in memory outside the CPU Data is loaded from memory and stored in memory Load word lw Store word sw 32 resgiters 230 words or 232 addressable locations or bytes 01 16 19 C language to Memory instructions 13 Base register concept base register is s3 and Offset of 32 for 8 words and offset of 48 for 12 words 01 16 19 Instruction Types 14 add and sub lw and sw Now lets see how we can deal with a constant value data Consider C language statement x x 4 Too complex lw t0 AddrConst s1 add s3 s3 t0 Instead how about addi s3 s3 4 Summary is in Fig 2 4 Design principle 3 Make the common case fast Example addi instead of add an constant from memory 01 16 19 Instruction format R type 15 Can we use the same format for addi and add Then we will Have only 11 bit constant 01 16 19 Instruction format I type 16 Design principle 4 good design demands good compromise Keep instruction length same needing different formats I and R type are examples 01 16 19 Summary 17 Figure 2 7 very nicely summarizes all we learned so far MIPS operands MIPS memory MIPS Assembly language MIPS instructions type and formats And of course the four design principles 01 16 19