How does variable valve timing (VVT) benefit an ICE engine?

Allows for adjustments to when valves open and close for improved performance and efficiency

Has no impact on engine operation

Decreases fuel efficiency and power output

Increases emissions and reduces speed

What is the main function of variable valve timing (VVT) in an ICE engine?

To optimize engine performance at different RPMs

To reduce the overall engine power

To limit the amount of air entering the combustion chamber

What is the role of the camshaft in variable valve timing (VVT) systems in an ICE engine?

To control the timing of valve opening and closing

To regulate the fuel injection process

To monitor the exhaust gas recirculation

To adjust the engine's compression ratio

How does variable valve timing (VVT) contribute to reducing emissions in an ICE engine?

By optimizing air-fuel mixture combustion for cleaner exhaust gases

By decreasing the engine's power output

By increasing engine load and emissions output

By restricting air intake into the combustion chamber

What is the role of the ECU (Engine Control Unit) in managing variable valve timing in an ICE engine?

The ECU adjusts valve timing based on engine parameters to optimize performance

The ECU changes the car's exterior color

The ECU tunes the car stereo system

The ECU controls the air conditioning system

How can variable valve timing in an ICE engine be adjusted?

By changing the phase of the camshaft relative to the crankshaft

By adding more windshield washer fluid

How is the intake valve controlled with variable valve timing in an ICE engine?

By adjusting the camshaft position

By increasing the tire pressure

By adjusting the fuel injection rate

Variable valve timing in ICE engine

Automotive engine variable valve timing

variable valve lift mechanism for ICE engine

Variable valve mechanism for ICE engine

Short Quiz in Math 7 solves linear equation or inequality in one variable involving absolute value

Multiple choice questions on the following : Context: Park A (Sharjah): 120, 122, 121, 119, 118 Park B (Dubai): 90, 130, 150, 110, 120 Both parks have the same mean number of visitors. What is the correct value of the mean? A. 118 B. 119 C. 120 D. 121 Without calculating variance fully, which park is most likely to have the larger population variance? A. Park A, because its values are closer to the mean B. Park B, because its values are more spread out C. Park A, because it has a smaller range D. Park B, because it has more visitors overall The mean number of visitors for both parks is 120. Which value contributes the MOST to the variance of Park B? A. 110 B. 120 C. 130 D. 150 What is the squared deviation of 90 visitors from the mean? A. 30 B. 60 C. 900 D. 30² Why does the value 150 increase the variance more than 130? A. It increases the mean B. Its deviation from the mean is larger before squaring C. It occurs later in the data set D. Variance depends only on the largest value Which statement best describes the visitor pattern in Park A (Sharjah)? A. Highly variable with extreme values B. Random and unpredictable C. Consistent with small deviations from the mean D. Skewed due to an outlier Both parks have the same mean. Why is variance still needed to compare them? A. The mean does not show how spread out the data is B. Variance changes the data values C. Variance affects the mean D. Variance replaces the mean A municipality wants to plan staffing using predictable visitor numbers. Based on variance, which park should be chosen? A. Park B, because it has higher peaks B. Park A, because it has lower variance C. Park B, because it has more visitors D. Either park, since the means are equal A student says: “Park B has greater variation because it has the largest value.” Which response best evaluates this claim? A. Correct, because variance depends only on the maximum value B. Partially correct, because variance depends on all deviations from the mean C. Incorrect, because variance ignores extreme values D. Incorrect, because variance only uses the mean If the value 150 were removed from Park B’s data, what would most likely happen to its variance? A. It would increase B. It would stay the same C. It would decrease D. It would become zero

Introduction to Hedging Instruments: Forwards, Futures, Options, and Swaps Hedging instruments are financial tools used by businesses and investors to mitigate risk. These instruments help protect against adverse price movements in assets such as commodities, currencies, interest rates, or securities. The four main hedging instruments are forwards, futures, options, and swaps. 1. Forwards A forward contract is a customised agreement between two parties to buy or sell an asset at a predetermined price on a specified future date. Key Characteristics: Over-the-counter (OTC): Traded directly between parties, not on an exchange. Customisation: Can be tailored to suit the needs of the parties involved. Settlement: Occurs at the end of the contract, which may involve physical delivery or cash settlement. Risk: Forwards carry counter-party risk, as there is a possibility one party may default. Example: A company that needs to import raw materials in six months may enter into a forward contract to lock in the current price, avoiding the risk of price increases. 2. Futures A futures contract is similar to a forward, but it is standardised and traded on an exchange. This standardisation eliminates counter-party risk. Key Characteristics: Standardised: Contract size, expiration, and other terms are fixed by the exchange. Mark-to-market: Gains and losses are settled daily. Liquidity: Futures are highly liquid because they are traded on exchanges. Regulation: As they are traded on formal exchanges, they are more regulated than forwards. Example: A wheat farmer may sell futures contracts to hedge against a possible decline in wheat prices before harvest. 3. Options Options provide the right, but not the obligation, to buy or sell an asset at a specified price on or before a certain date. There are two types of options: call options and put options. Call Option: Gives the holder the right to buy an asset at a predetermined price. Put Option: Gives the holder the right to sell an asset at a predetermined price. Key Characteristics: Premium: The buyer pays a premium upfront to obtain the option. Limited Risk: The maximum loss is limited to the premium paid. Flexibility: Options can be used for speculative or hedging purposes. Example: An investor holding stocks may buy a put option to protect against potential declines in the stock's price. 4. Swaps A swap is a contract in which two parties agree to exchange cash flows or liabilities over a specific period. The most common types are interest rate swaps and currency swaps. Key Characteristics: Customizable: Like forwards, swaps are often tailored to meet the needs of the parties involved. Counterparty Risk: Swaps are typically OTC instruments, exposing parties to default risk. Common Uses: Used to manage interest rate risk or currency risk. Example: A company with a variablerate loan may enter into an interest rate swap to exchange its variable payments for fixedrate payments, thus locking in stable costs. Hedging instruments are essential for managing financial risk in volatile markets. Each instrument serves different purposes, with varying levels of complexity, risk, and customization. Whether through forwards, futures, options, or swaps, businesses can better plan for the future by reducing exposure to uncertain price fluctuations. Hedging Strategies for Market Risk, Credit Risk, and Currency Risk 1. Hedging Strategies for Market Risk Market risk (also known as systematic risk) arises from fluctuations in asset prices, such as stocks, bonds, commodities, and interest rates, due to economic factors or market volatility. Key Hedging Instruments for Market Risk: Derivatives (Options, Futures, and Forwards): These instruments allow investors to hedge against unfavorable price movements in stocks, commodities, or interest rates. Example: An investor holding a large stock portfolio might buy a put option to protect against a potential market downturn. If the market declines, the put option increases in value, offsetting losses in the portfolio. Short Selling: Investors can sell borrowed assets with the expectation of buying them back at a lower price, profiting from the decline. Example: A fund manager expecting a market decline may short sell stocks to hedge a portfolio against losses. Common Hedging Strategies: Portfolio Diversification: Reducing market risk by spreading investments across various asset classes (stocks, bonds, commodities) and sectors. Using Index Futures: Large portfolios can be hedged using index futures that track the performance of the overall market. If the market declines, profits from the short position in the futures contract will offset losses in the portfolio. Risk Parity: Allocating assets based on the level of risk rather than the dollar amount invested, balancing risk exposure across asset classes. 2. Hedging Strategies for Credit Risk Credit risk refers to the possibility that a borrower will default on a debt obligation. This is especially important for banks, lenders, and institutions dealing with bonds and loans. Key Hedging Instruments for Credit Risk: Credit Default Swaps (CDS): A financial derivative where the buyer of a CDS pays a premium to the seller in exchange for protection against a default on a loan or bond. Example: A bank holding corporate bonds can buy a CDS to ensure they are compensated if the issuing company defaults. Collateralised Debt Obligations (CDOs): These instruments pool together various debt instruments and allow risk to be distributed among multiple investors. Credit Insurance: Companies may use insurance to protect against the risk of a customer defaulting on payments. Common Hedging Strategies: Diversification of Loan Portfolio: Spreading out credit exposures across various industries, geographies, and borrower profiles reduces the overall risk of default. Tightening Lending Standards: Limiting exposure to highrisk borrowers by implementing stringent credit assessments. AssetBacked Securities: Banks can sell loans or bonds packaged as assetbacked securities to reduce their exposure to credit risk. 3. Hedging Strategies for Currency Risk Currency risk (or exchange rate risk) arises from fluctuations in foreign exchange rates, which can affect companies involved in international trade or with investments in foreign countries. Key Hedging Instruments for Currency Risk: Forward Contracts: A firm agrees to exchange a specified amount of currency at a predetermined exchange rate on a future date. Example: A U.S. exporter expecting payment in euros might enter into a forward contract to sell euros and lock in a favorable exchange rate. Currency Options: These give the right, but not the obligation, to buy or sell currency at a specific price. Example: A U.S.based company buying goods from Japan might buy a call option on the yen to hedge against the risk of yen appreciation. Currency Swaps: Two parties exchange interest payments and principal in different currencies to hedge against exchange rate fluctuations. Common Hedging Strategies: Natural Hedging: Companies can offset currency risk by balancing foreign revenue with costs in the same currency. For example, if a company generates revenue in euros, it can also incur expenses in euros, reducing exposure to exchange rate fluctuations. Multi-Currency Invoicing: Firms can invoice in their home currency, shifting the currency risk to the buyer. Currency Diversification: Holding a diversified basket of currencies can reduce exposure to large fluctuations in any one currency. Effective hedging strategies are crucial for managing various types of risks in financial markets. Market risk can be managed using instruments like futures and options, while credit risk can be mitigated through diversification and credit derivatives. Currency risk, often faced by multinational firms, can be hedged using forward contracts, options, or swaps. Each strategy helps firms and investors protect their portfolios, ensure financial stability, and reduce the impact of adverse movements in the financial markets. Portfolio Risk Management Techniques: Diversification, Asset Allocation, and Risk Budgeting Managing risk is a fundamental aspect of portfolio management. Investors use various techniques to control and reduce the risks inherent in investing. Three key techniques used in portfolio risk management are diversification, asset allocation, and risk budgeting. Each of these techniques helps in mitigating potential losses while aiming to achieve the desired return. 1. Diversification Diversification is a risk management strategy that involves spreading investments across different assets, sectors, or geographic regions to reduce exposure to any single risk. The idea is that different assets perform differently under various market conditions, so losses in one investment can be offset by gains in others. Key Benefits of Diversification: Reduction of Unsystematic Risk: Unsystematic risk, which is unique to a specific company or industry, can be reduced by holding a variety of investments that respond differently to market conditions. Improved Stability: A diversified portfolio is less volatile, as the negative performance of one asset can be balanced by the positive performance of others. Methods of Diversification: Across Asset Classes: Investing in a mix of asset classes such as stocks, bonds, commodities, and real estate. Example: A portfolio with 60% equities, 30% bonds, and 10% commodities is more diversified than one solely consisting of stocks. Within Asset Classes: Diversifying within a single asset class (e.g., holding stocks from different sectors like technology, healthcare, and energy). Geographic Diversification: Investing in assets across various countries or regions to mitigate country-specific risks. Example: Holding U.S. stocks along with emerging market equities can reduce risks related to a downturn in one country's economy. 2. Asset Allocation Asset allocation refers to the process of dividing investments among different asset classes (such as stocks, bonds, and cash) to align with an investor's risk tolerance, time horizon, and financial goals. Asset allocation plays a crucial role in portfolio risk management by determining the overall risk-return profile of the portfolio. Key Elements of Asset Allocation: Strategic Asset Allocation: A longterm approach that involves setting target allocations for different asset classes based on financial goals and risk tolerance. Example: A young investor with a longterm horizon might allocate 70% to stocks, 20% to bonds, and 10% to cash. Tactical Asset Allocation: A more active approach that involves adjusting the asset mix in response to short-term market conditions. Example: If the investor expects an economic downturn, they might temporarily reduce exposure to equities and increase exposure to bonds. Types of Asset Allocation Models: Conservative: Focuses on preserving capital with a larger allocation to bonds and cash (e.g., 20% stocks, 80% bonds). Balanced: A moderate risk approach with an equal focus on growth and income (e.g., 50% stocks, 50% bonds). Aggressive: Targets higher returns by investing predominantly in equities, accepting higher risk (e.g., 80% stocks, 20% bonds). Example of Asset Allocation: A 40 year old investor with moderate risk tolerance may allocate their portfolio as follows: 50% equities, 40% bonds, and 10% in alternative investments such as real estate or commodities. The equities provide growth potential, while the bonds and alternative assets offer stability and income. 3. Risk Budgeting Risk budgeting is a method of allocating risk across different components of a portfolio, rather than focusing solely on returns. The goal is to optimise the portfolio’s risk-return profile by distributing risk in a way that aligns with the investor’s objectives and risk tolerance. Key Concepts of Risk Budgeting: Risk Contribution: Each asset class or investment in the portfolio contributes a certain amount of risk (measured by metrics such as volatility or Value at Risk). Risk budgeting ensures that no single asset class dominates the overall risk of the portfolio. Example: A portfolio may contain 60% stocks and 40% bonds, but if the stocks are highly volatile, they may contribute 90% of the portfolio's risk. Target Risk: Investors set a maximum acceptable level of risk (e.g., a portfolio volatility of 10%) and allocate investments so that the total risk remains within this target. Techniques in Risk Budgeting: Risk Parity: Allocates risk evenly across asset classes, rather than allocating capital based solely on return expectations. Example: In a risk-parity portfolio, both bonds and stocks might be balanced in such a way that they contribute equally to the overall portfolio risk, even though the dollar investment in bonds may be larger due to their lower volatility. Value at Risk (VaR): This technique measures the potential loss in a portfolio over a specific time period, under normal market conditions, at a given confidence level. The risk budget ensures that the potential loss stays within acceptable limits. Example of Risk Budgeting: An investor targets an overall portfolio risk of 8% volatility. After analyzing the risk contribution of each asset class, they determine that equities, which currently make up 60% of the portfolio, contribute 70% of the risk. To adhere to the risk budget, the investor may reduce their equity exposure and increase their allocation to bonds or other less volatile assets. Diversification, asset allocation, and risk budgeting are complementary techniques used in portfolio risk management. Diversification reduces unsystematic risk by spreading investments across various assets. Asset allocation ensures that investments align with an investor's goals and risk tolerance. Risk budgeting focuses on managing the contribution of risk from each asset class to create a balanced and efficient portfolio. Together, these strategies help investors achieve a balance between risk and return, ensuring longterm portfolio stability. Risk Mitigation Through Insurance, Securitisation, and Other Financial Engineering Techniques Risk mitigation is a core objective in financial management, and various strategies can be employed to reduce or manage risks. Three major approaches are insurance, securitisation, and financial engineering techniques. Each of these methods helps firms and individuals transfer, reduce, or eliminate certain financial risks. 1. Insurance as a Risk Mitigation Tool Insurance is a traditional risk transfer method that protects against financial losses by shifting the risk to an insurance company in exchange for premium payments. It is widely used to mitigate various forms of risk, such as operational, liability, and property risks. Key Aspects of Insurance for Risk Mitigation: Risk Transfer: The insurer takes on the risk in exchange for a premium, thus protecting the insured party from unexpected financial losses. Indemnity: In the event of a loss, the insurance policy compensates the insured based on the terms of the contract. Customisable Coverage: Insurance policies can be tailored to address specific risks, such as property damage, business interruption, liability, or cyber risks. Types of Insurance for Businesses: Property and Casualty Insurance: Covers physical assets like buildings, machinery, and inventory from risks like fire, theft, or natural disasters. Liability Insurance: Protects businesses against legal liabilities arising from accidents, negligence, or professional errors. Business Interruption Insurance: Compensates for lost income if a business has to halt operations due to unforeseen events. Credit Insurance: Shields companies from losses due to the nonpayment of trade receivables. 2. Securitisation as a Risk Mitigation Technique Securitisation is a financial engineering process that involves pooling various financial assets (such as loans, mortgages, or receivables) and converting them into marketable securities. This process allows firms to transfer risk to investors, thereby reducing their exposure. Key Elements of Securitisation: Risk Transfer: By securitising assets, companies can transfer the risk of default or nonpayment to investors who purchase the securities. Liquidity Creation: Securitisation converts illiquid assets (like mortgages or loans) into liquid, tradeable securities, improving cash flow for the originating firm. Diversification of Risk: Pooling assets with different risk profiles reduces the impact of individual defaults, spreading the risk across multiple investors. Common Forms of Securitisation: MortgageBacked Securities (MBS): Pools of mortgages are bundled and sold as securities to investors, transferring the risk of mortgage defaults. Example: A bank that issues home loans can bundle those loans into MBS and sell them to investors, transferring the credit risk of potential defaults. Asset-Backed Securities (ABS): Similar to MBS, but backed by other types of assets like credit card receivables, auto loans, or student loans. Collateralised Debt Obligations (CDOs): Structured financial products that pool different types of debt, such as loans and bonds, and sell them as securities with varying risk levels. Example: A bank may issue a portfolio of auto loans and then pool these loans into an assetbacked security (ABS). The ABS is sold to investors, who take on the risk of loan defaults. By securitising the loans, the bank reduces its exposure to credit risk and generates immediate cash flow. 3. Financial Engineering Techniques for Risk Mitigation Financial engineering involves the use of complex financial instruments, derivatives, and structured products to manage or mitigate financial risks. These techniques allow firms to hedge against specific risks, optimize capital structure, and improve financial stability. Common Financial Engineering Techniques: Derivatives: Financial instruments like futures, forwards, options, and swaps are used to hedge against price fluctuations, interest rate changes, or currency movements. Example: A company with significant foreign exchange exposure may use currency forwards or options to hedge against exchange rate fluctuations, ensuring predictable cash flows. Options and Futures: Options: Provides the right (but not the obligation) to buy or sell an asset at a predetermined price, allowing firms to hedge against unfavorable price movements. Example: An airline company can buy options on jet fuel to hedge against rising fuel prices. Futures: Standardized contracts to buy or sell an asset at a set price on a future date, commonly used to hedge commodities or financial assets. Example: A wheat producer may use futures contracts to lock in a favorable price for its crop, hedging against a potential price drop. Swaps: These involve the exchange of cash flows between two parties, often used to manage interest rate risk or currency risk. Interest Rate Swaps: Firms can exchange floatingrate interest payments for fixedrate payments to hedge against rising interest rates. Currency Swaps: Used to hedge exchange rate risk in crossborder transactions by exchanging principal and interest payments in different currencies. Example: A company with a variablerate loan may enter into an interest rate swap to exchange its variable payments for fixedrate payments, locking in stable costs. Structured Products: These are customised financial instruments designed to achieve specific riskreturn objectives. They often combine derivatives with other securities to create tailored risk exposures. Example: A structured note that combines a bond with an embedded option, offering downside protection while allowing for potential upside linked to the performance of an equity index. Credit Derivatives: Tools like credit default swaps (CDS) allow investors to transfer credit risk to other parties. Example: A bondholder worried about a company’s potential default may purchase a CDS, which pays out in case of a default event. Example: A company may issue a bond with an embedded call option, allowing it to repurchase the bond if interest rates decline. This financial engineering tool enables the company to mitigate the risk of rising interest rates, reducing future borrowing costs. Risk mitigation through insurance, securitisation, and financial engineering offers businesses a variety of tools to manage and transfer risks. Insurance allows for the direct transfer of risk to an insurer, while securitisation helps companies offload risk by packaging and selling assets as securities. Financial engineering techniques, including derivatives, swaps, and structured products, provide sophisticated ways to hedge market, interest rate, and currency risks. Each approach helps organizations improve financial stability, enhance liquidity, and manage potential losses in a volatile market environment.

In this video we take a look at the 0:02 fetch to code 0:03 execute cycle including its effect on 0:06 the various registers we've previously 0:12 [Music] 0:14 discussed a computer is defined Definition 0:17 as an electronic device that takes an 0:20 input 0:22 processes data 0:25 and delivers output 0:29 in this simple example you can see we're 0:31 taking the input 5 0:35 we're multiplying it by 2 that's our 0:37 process 0:39 and we're outputting 10. 0:44 but this could be way more complex for 0:46 example of a game console 0:48 the input could be the buttons you press 0:50 on a controller 0:53 the processes would then be carried out 0:55 by the console itself 0:59 and the output would be some form of 1:01 update to a monitor 1:02 and sound out for a speaker possibly 1:04 vibration feedback through the 1:06 controller 1:10 to process data a computer follows a set 1:13 of instructions 1:14 known as a computer program 1:18 if we take the lid off a typical desktop 1:20 computer we can identify 1:22 two critical components the memory 1:26 that stores the program and the central 1:29 processing unit or processor 1:31 which is under this large fan and 1:33 carries out the instructions 1:37 a computer carries out its function by 1:40 fetching 1:41 instructions decoding them and then 1:43 executing them 1:44 in a continuous repetitive cycle 1:46 billions of times a second 1:48 let's look at each of these stages in a 1:50 little more detail Fetch 1:53 so let's start with the fetch stage the 1:55 very first thing that happens 1:57 is the program counter is checked as it 2:00 holds the address 2:01 of the next instruction to be executed 2:07 the address stored is then copied into 2:09 the memory address register 2:14 the address is then sent along the 2:16 address bus to main memory 2:18 where it waits to receive a signal from 2:21 the control 2:22 bus so it knows what to do 2:27 as we want to read the data that's 2:29 stored in memory address 2:30 0 0 0 0 the control unit sends 2:34 a read signal along the control bus to 2:36 main memory 2:41 now main memory knows the data needs to 2:44 be read 2:45 the content stored in memory address 000 2:49 can be sent along the data bus to the 2:51 memory data register 2:56 now as we're currently in the process of 2:58 fetching an instruction 3:00 the data received by the memory data 3:03 register gets copied 3:04 into the current instruction register 3:11 the instruction effectively has now been 3:14 fetched from memory 3:16 just before we proceed to the decode 3:18 phase we now 3:19 increment the program counter so that 3:22 the address it contains 3:24 points to the address of the next 3:26 instruction which will need to be 3:30 executed 3:32 the instruction now being held in the 3:33 current instruction register 3:35 is ready to be decoded 3:39 now as we mentioned in the previous 3:41 video the instruction is made up of two 3:43 parts 3:44 we have the op code that's what it is we 3:47 need to do 3:50 and we have the operand what are we 3:53 going to do it to 3:55 now the operand could contain the actual 3:57 data 3:58 or indeed it could contain an address of 4:01 where the data is to be found 4:06 by decoding this instruction we can see 4:08 the operation we need 4:10 is a load operation so we need to load 4:14 the contents of memory location0101 4:18 into the cpus accumulator 4:25 in the exam a simple model will be used 4:27 to describe the 4:29 structure of any given instruction 4:32 you're not going to be expected to 4:34 define how an opcode is made up 4:36 but simply to interpret opcodes in the 4:39 given context of an exam 4:40 question in the example here 4:44 you can see there's a total of 16 4:46 different opcodes available 4:48 and this is because we're using four 4:50 bits for our representation 4:56 so now we've fetched the instruction and 4:59 we've decoded it so we know what we need 5:00 to do 5:01 we're finally ready to execute it 5:05 so we now send address 0101 5:08 to the memory dress register 5:13 now we're in the memory address register 5:15 we can finally send the address 5:18 down the address bus to main memory 5:24 this time we want to read the data 5:26 that's stored in memory 5:28 and so the control unit again sends a 5:30 read signal along the control bus 5:36 so main memories now receive an address 5:38 and a read signal 5:40 so the content stored at memory location 5:43 0101 5:44 can now be sent along the data bus back 5:46 to the cpu 5:47 and into the memory data register 5:54 finally the contents of the memory data 5:56 register are copied to the accumulator 5:59 and this is one of a number of general 6:00 purpose registers found in the cpu 6:04 this first instruction is now complete Branching 6:11 so what does this program actually do 6:14 you should be able to work it through 6:16 carefully and figure it out 6:19 we're now pointing instructions zero 6:21 zero zero one in the program counter 6:23 and we're ready to fetch the second 6:25 instruction 6:27 at the end of this video we're gonna 6:29 provide you with the answer 6:34 so let's talk a second about programs 6:37 that branch 6:40 on the left here we have a very simple 6:42 piece of pseudo code 6:44 line zero says first execute this line 6:46 of code 6:47 line 1 now execute this line and then 6:50 line 2 says 6:52 if the age is greater than 18 then 6:56 we're going to execute lines 3 and 4 6:58 otherwise 6:59 we're going to execute lines six and 7:02 seven 7:03 so this program doesn't necessarily 7:05 follow strictly in sequence from line 7:07 zero through to seven there's a chance 7:10 here the program may branch and jump 7:14 around 7:16 so we're going to pretend that this 7:17 program has been loaded into memory 7:20 each line of code on the left here has 7:23 ended up 7:24 as a location in memory now this is not 7:27 strictly how this would happen in this 7:28 one-to-one way 7:29 but for the purpose of example it's 7:31 absolutely fine 7:35 so the program counter starts by 7:37 pointing to memory address zero 7:39 and we fetch the first instruction 7:41 decode it and execute it 7:44 it then updates and tells us the next 7:47 instruction 7:48 is zero zero zero one because remember 7:50 the program counter is being incremented 7:52 so we fetch it decode it and we execute 7:55 line one of our program 7:59 we then fetch line two which in binary 8:01 is one 8:02 zero 8:06 now at this point depending on what 8:10 happens during the execution 8:11 of line two the program may be required 8:15 to fetch line three from memory or 8:18 line five from memory 8:25 so let's look at how this actually works 8:27 because we've said the program counter 8:28 simply gets incremented 8:31 well in the current instruction register 8:33 we have an instruction with the op code 8:36 0 1 1 0. 8:41 now when we look this up in the decode 8:43 unit we discover that this 8:45 code means branch always 8:51 this replaces the value held in the 8:54 program counter 8:56 with the contents of the operand that's 8:58 the second part of the instruction 9:01 from the current instruction register so 9:03 this case 9:04 one zero zero one 9:09 now when the next fetch cycle begins the 9:12 program counter is obviously checked 9:14 and as its contents have been previously 9:16 updated to a new memory location 9:19 and not simply incremented the program 9:22 effectively is able to jump 9:24 around memory 9:28 so having watched this video you should 9:30 be able to answer the following key 9:32 question 9:33 how does a cpu work 9:39 okay so let's um answer the question we 9:41 posed 9:42 earlier what did that program actually 9:48 do 9:50 so this is the first fetch to code 9:53 execute cycle 9:55 and this is the one that we ran through 9:57 in detail earlier 9:58 it effectively loaded the contents of 10:01 the memory 10:02 stored at location location0101 10:05 into the accumulator in other words 10:08 the dna number 3 is moved 10:11 from memory into the cpu 10:18 we then proceed onto the second fetch 10:20 decode execute cycle 10:23 now this one adds the contents of memory 10:27 located at 0 1 1 0 10:30 to the current contents of the 10:32 accumulator 10:34 so in other words the dna number one 10:38 because that's what's stored at address 10:40 zero one one zero 10:43 is added to the number three that was in 10:45 the accumulator 10:46 the results are stored back over the 10:48 accumulator 10:49 so effectively we've done three plus one 10:53 equals four 10:58 the third fetch to code execute cycle 11:00 stores the contents which are in the 11:02 accumulator 11:03 into memory location zero one one one 11:07 and that's because the op code the first 11:09 part of this current instruction 11:10 zero zero one one is the command to 11:13 store when we look it up in the decoder 11:15 unit 11:16 so in other words the result of the 11:17 previous calculation three plus one 11:19 equals four 11:20 is now written back into main memory 11:28 the fourth fetch decode execute cycle 11:30 outputs the contents of the accumulator 11:33 remember they were copied into main 11:34 memory but they're still held in the 11:35 accumulator 11:37 so in this simple abstraction the number 11:40 four is now 11:41 output to the user so they can see the 11:43 result of the calculation 11:49 the fifth and final fetch code execute 11:51 cycle 11:52 brings a halt to the current program 11:58 so this very simple program which has 12:01 five 12:02 fetch decode execute cycles has 12:04 performed the calculation 12:06 three plus one is then stored the result 12:09 in main memory 12:10 and displayed the result four to the 12:12 user 12:13 and in a high-level language this may 12:15 look something very similar to the 12:17 following two lines of code 12:20 sum variable equals num1 plus num2 12:24 print sum to the user 12:27 so you can start to get an appreciation 12:29 here of how the high level code you 12:32 write actually ends up being fetched 12:34 decoded 12:35 and executed inside a processor 12:38 of course your processor is doing 12:40 billions and billions of these 12:42 operations a second 12:43 which when you think about it is really 12:45 very impressive 12:52 [Music] 13:03 you. make 10 questions for a standerd of a level

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