6 Step of Program Execution

1.      (Instruction Making)

The first step , the PC contains the numbers 300. where the 300 numbers come from the first address given command of the memory . Then , the command in hexadecimal form (1940 ) entered and stored in the IR so that the value of IR into 1940 .

2.      (Instruction Execution)

In the 2nd Step, after IR contains the value 1940, it resulted in the AC must be filled with the value at address 940. Why 940 choosen ? Not another address such as 450 , 560 or another , it happens because the value of the AC is to be filled using the value of the IR itself. In other words , the value of the AC will adjust the value contained in the IR because we will take 3 hexadecimal digits contained in the IR . In this example the value of the IR 1940, then the existing values ​​are taken at address 1940 ( 940 ).

3.      (Instruction Making)

After the contents of the PC plus one (incremented) So that it becomes 301 means that the next instruction to be fetched from memory and executed is located in memory address 301 , the instruction with code 5941. Then , the order of the address stored in the memory 301 so that the value of the IR 5941 and IR -value PC worth 301 .

4.      (Instruction Execution)

The fourth step , the AC will take the value contained at the address 941. However , the AC does not change as the PC and IR , AC will ditambkan with the previous value 0003. So the value of the AC current into 0005 ( 0002 were found in step 3 + 0003 contained in the second step ) . Why not change the absolute AC or added , because the AC own the temporary storage so that its value will be added until the program exits .

5.      (Instruction Making)

After that PC plus one , then it becomes 302 , so that the next instruction is retrieved from memory address 302 is 2941 , then the command in hexadecimal form ( 2941 ) of 302 memory address entered and stored in the IR so that the value of IR into 2941 and the PC.

6.      (Instruction Execution)

The final step is to move the AC value into memory address 941. 2941 mean is the command to copy the contents of the accumulator to memory address 941 .

CISC (Von Neumann) VS RISC (Harvard)

    

          The Instruction set architechture (ISA) is plays an important role in the microprocessors. There are different instruction set architechture microprocessors available in them market, they are:

1.    Complex Programming Instruction Set Computer (CISC)

This was first ISA. In the complex instruction set computer (CISC) instruction set is complex instruction which will take long time to execute. Complex instruction may consist of opcode addressing mode operand etc. The execution speed will be slow. X86 architechture is the example.

2.    Reduced Instruction Set Computer (RISC)

In the reduced instruction set computer (RISC), the instruction set will be small and execution speed will be fast. The implementation is simple and does not require complex architechture. RISC is widely used in embedded applications. SHARC and POWERPC use RISC.

There are some differences between CISC and RISC:

CISC	RISC
Very large instruction sets reaching up to and above three hundred separate instruction.	Small set of instruction.
Performance was improved by allowing the simplification of program compilers, as the range of more advanced instructions available led to less refinements having to be made at the compilation process. However, the complexity of the processor hardware and architecture that resulted can cause such chips to be difficult to understand and program for, and also means they can be expensive to produce.	Simplified and reduced instruction set, numbering one hundred instruction or less. Because of simple instructions, RISC chips requires fewer transistors to produce processors. Also the reduced instruction set means that the processor can execute the instructions more quickly, potentially allowing forgreater speeds. However, only allowing such simple instructions means a greater burden is placed upon the software itself. Less instruction in the instruction set means a greater emphasis on the efficient writing of software with the instructions that are available.
More specialized addressing modes and registers also being implemented, with variable length instruction codes.	Addressing modes are simplified back to four or less, and the length of the codes is fixed in order to allow standardization across the instruction set.
Instruction pipelining can not be implemented easily.	Instruction pipelining can be implemented easily.
Many complex instructions can access memory, such as direct addition between data in two memory locations.	Only LOAD/STORE instructions can access memory.
Mainly used in normal PC’s, workstations and servers.	Mainly used for real time applications.
CISC systems shorten time by reducing the number of instruction per program.	RISC systems shorten execution time by reducing the clock cycles per instruction (i.e. simple instructions take less time to interpret.
Examples of CISC Processors: Intel x86.	Examples of RISC Processors: Atmel AVR, PIC, ARM.

Some differencess between Von-Neumann and Harvard:

VON -NEUMANN	HARVARD
It is named by early computer scientist John Von Neumann.	This name is oridinated by “Harvard Mark I” a relay based old computer.
The computer has single storage system for storing data as well as program to be executed.	The omputer has two separate memories for storing data and program.
Processor needs two clock cycles to complete an instructions is not possible with this architecture.	Procesor can complete an instruction in one cycle if appropriate-pipelining strategies are implemented.
In the first clock cycle the processor gets the instruction from memory and decodes it. In the next clock cycle the required data is taken from memory. For each instruction this cycle repeats and hence needs two cycles to complete an instruction.	In the first stage of pipeline the instruction to be executed can be taken from program memory. In the second stage of pipeline data is taken from the data memory using the decoded instruction or address.
This is a relatively older architecture and was replaced by Harvard architecture.	Most of the modern computing architectures are based on Harvard architecture. But the number of stages in the pipeline varies from system to system.

            There are other architecture like Very Long Instruction word (VLIW) and FUSION of RISC and CISC architecture etc.

            Microprocessor should be choosen according to the application for small application you don’t need CISC. You cannot use RISC for large application. According to the application and peripherals you are using micro processor should be taken.

www.electronicshub.org

https://bookstreet.in

Control Unit (CU)

Control Unit (CU)

A control unit is circuitry that directs operations within the computer's processor by directing the input and output of a computer system. The processor then controls how the rest of the computer operates (giving directions to the other parts and systems). A control unit works by gathering input through a series of commands it receives from instructions in a running programs and then outputs those commands into control signals that the computer and other hardware attached to the computer carry out.

The control unit is basically circuitry inside the CPU, controlling the operations inside the CPU and "directing traffic" in a sense. The functions a control unit performs can depend on the type of CPU, since the varying degrees of architecture between all the different CPUs determine the functions of the control unit.

A CU takes its input from the instruction and status registers. Its rules of operation, or microprogram, are encoded in a programmable logic array (PLA), random logic or read-only memory (ROM).

CU functions are as follows:

• Controls sequential instruction execution
• Interprets instructions
• Guides data flow through different computer areas
• Regulates and controls processor timing
• Sends and receives control signals from other computer devices
• Handles multiple tasks, such as fetching, decoding, execution handling and storing results

CUs are designed in two ways:

• Hardwired control: Design is based on a fixed architecture. The CU is made up of flip-flops, logic gates, digital circuits and encoder and decoder circuits that are wired in a specific and fixed way. When instruction set changes are required, wiring and circuit changes must be made. This is preferred in a reduced instruction set computing (RISC) architecture, which only has a small number of instructions.
• Microprogram control: Microprograms are stored in a special control memory and are based on flowcharts. They are replaceable and ideal because of their simplicity.

http://www.computerhope.com/

http://www.techopedia.com/

Awesome Nature at Surakarta

pagi itu di langit asrama 25 September 2013 :)

 26 Desember 2013

9 Oktober 2013

12 November 2013

gambar ini saya ambil di International Boarding School K.H Mas Mansyur :)

awesome nature at Tawangmangu

Gambar diatas saya ambil ketika saya mengikuti kegiatan Masa Pengakraban (MAKRAB) salah satu UKM di kampus saya tanggal 22 September 2013 :)

Lirik lagu Mine - Petra feat. Ben Sihombing

Girl your heart, girl your face
is so different from them others
I say, you're the only one that I'll adore

Cos everytime you're by my side
My blood rushes through my veins
And my geeky face, blushed so silly oo yeah, oyeah

And I want to make you mine

Reff :
Oh baby I'll take you to the sky
Forever you and I, you and I
And we'll be together till we die
Our love will last forever and forever you'll be mine,
you'll be mine

Girl your smile and your charm
Lingers always on my mind
I'll say, you're the onlyone that I've waited for