Presentation on theme: "Microprocessor and Assembly Language. History of Microprocessor A microprocessor (sometimes abbreviated µP) is a digital electronic component with transistors."— Presentation transcript:
Microprocessor and Assembly Language
History of Microprocessor A microprocessor (sometimes abbreviated µP) is a digital electronic component with transistors on a single semiconductor integrated circuit (IC). A Central processing unit (CPU) in a computer system or handheld device consists of one or more microprocessors.
A Microprocessor is essentially a set of switches. Using photographic technology a massive set of electronic switches is superimposed onto a very small piece of silicon. Through the use of binary language, which consists of only two states; one and zero (on and off), these can be used to store information and perform operations on it.
A bit refers to one binary digit; a zero or one. In computer memory and processing this refers to the state of one switch. The transistors are arranged into groups in order to represent complex numbers and instructions
The very first microprocessor is considered to be the Intel 4004. It was released in 1971 and was a 4 Bit processor. Then the 8 bit 8008 microprocessor. It was developed by Intel in 1972 The first multi-chip 16 bit processor was released by National Semiconductor in 1973 Intel upgraded the 8008 into a 16 bit version they called the 8086. It was the first of the x86 family by which many modern PCs are powered.
32 bit designs didn't require much to improve performance since it has double the size of instructions as well as the amount of addressable memory. 68000 by Motorola was one of the first microprocessors developed to 32 bit architectures. It was released in 1979 and continued to be in use today.
Most of today's computers are turning to 64 bit designs to handle dealing with very large amounts of data. This is needed especially as demand for 3D Graphics and fast video has risen. E.g. AMD Athlon, Pentium i5/i7 processors.
Microprocessors are classified into different types on the basis of the bit of operation. Based on bit of operation at a time, the following are the types of microprocessors: ==> 4 bit. e.g. Intel 4004 ==> 8 bit. e.g. Intel 8085, 8088, Zilog Z80, Z180 ==> 16 bit. e.g. Intel 8086, 80186, 80286, 80386, ==> 32 bit. e.g. Intel Pentium, Celeron, AMD Sempron ==> 64 bit. e.g. AMD Athlon. Based on the instruction set microprocessors are classified into: RISC Reduced Instruction Set Computing. These types of processors are commonly used in ovens, air conditioners, etc. CISC Complex Instruction Set Computing. The types of processors are used in desktops, laptops and servers.
Microcomputer Block Diagram
Basic Block Diagram of Microprocessor Arithmetic and Logic Unit (ALU) Register Array Timing and Control unit ALU – Performs all arithmetic and logical operations Register array – Holds the data temporarily for processing Control Unit – It supervises/ monitors all the operations carried out in the computer
The 8085 Microprocessor The 8085 microprocessor was introduced by Intel in the year 1976. This microprocessor is an update of 8080 microprocessor. The 8080 processor was updated with Enable/Disable instruction pins and Interrupt pins to form the 8085 microprocessor. It is an 8-bit microprocessor with a 40 pin dual in line package
Pin Diagram of a Basic 8085 Microprocessor
Flag Reg Instruction Reg Instruction decoder Address Buffer A8-A15 BCBC DEDE HLHL Stack Pointer Program Counter Incrementer/ Decrementer Address latch Data/address Buffer AD0-AD7 Temp. Reg Accumulator Arithmetic and Logic Unit Timing and Control unit RAM memory 8-bit_Internal_databus Intel 8085 Microprocessor Architecture 8- bit External Data bus ReadWriteClock
The 8085 has a set of registers for performing various operations. The various registers include: Accumulator – 8 bit register which holds the latest result from ALU B, C, D, E, H and L are general purpose registers HL pair can be used for indirect addressing as well Program counter – 16 bit register which holds the address of the next instruction to be executed Instruction register – It holds the instruction that is currently being processed. Stack pointer is used during subroutine calling and execution. Address Latch – It increments/ decrements the address before sent to the address buffer
Various Flags Sign Flag:If the result of the latest arithmetic operation is having MSB ( most- significant byte) 1 (meaning it is a negative number), then the sign flag is set. Otherwise, it is reset to 0 which means it is a positive number. Zero flag: If the result of the latest operation is zero, then zero flag will be set; otherwise it be reset. Auxiliary Carry Flag: This flag is not accessible to programmer. This flag will be used by the system during BCD ( binary-coded decimal) operations. Parity Flag: If the result of the latest operation is having even number of 1s, then this flag will be set. Otherwise this will be reset to 0. This is used for error checking. Carry Flag: If the result of the latest operations exceeds 8-bits then this flag will be set. Otherwise it be reset.
An example assembly language program Address Instruction 202AMVIA, 21;Copies 21 into accumulator 202CMVIB, 2A;Copies 2A into B register 202EADDB;Adds B reg content with Acc and stores the result in Acc. 202FSTA41 FF; Stores the Acc (the sum) into the memory location 41 FF. 2032HLT; Stops the program
Memory storage of the Assembly language AddressInstruction/Data 202AMVIA, 202B21 202CMVIB, 202D2A 202EADDB 202FSTA 2030FF 2031 41 2032HLT
Another example assembly language program Address Instruction 2020MVIB, 24;Copies 24 into accumulator 2022INRB;Increment B reg content by 1 2023MOVA, B;Copies B register into Acc. 2024SUBB;Subtracts B reg content from Acc and stores the result in Acc. 2025STA5F FF; Stores the Acc content into the memory location 5F FF. 2028HLT; Stops the program