31.3.1. Immediate Addressing Mode Example

So, what is this I am effectively trying to do? So, in this case register 𝑅5 will be 𝑅5 plus what is the content of the memory location how can you find out if whatever is 𝑅1 will be added to the content of the memory location how the memory location is calculated it is content of 𝑅1 + 1.

In the immediate addressing mode, immediate values can be directly specified in the instructions. In this case, register R5 is updated by adding the content of a specific memory location to it. The address of this memory location is determined using the value stored in register R1, which is incremented by 1 during the operation. Essentially, we are fetching a value from memory based on a computed address and then performing an addition operation with R5.

Think of R5 as a savings account balance. If you want to update your balance (R5) based on money that was just transferred into your account (content from memory), you first need to know how much was transferred (the value at the address calculated from R1 + 1) before you can add it to your current balance.

So, initially they are assuming that 𝑅1 is having the value of 1 and 𝑅5 has the value of 0 that is 𝑅5 is reset. So, if will be something like 𝑠 = 𝑠 + 𝑖.

In this task, register R1 starts with a value of 1, and R5 is initiated or reset to 0. This sets the stage for our operation. We can visualize this as the process of adding, where 's' represents our balance (R5) starting at 0, and 'i' represents a value being added from memory. Hence, the operation is akin to updating a value with a new incoming amount from memory based on the current address derived from R1.

Imagine you're starting with zero savings (R5 = 0), and you're anticipating your next payday (the value from the memory address), which you know will be deposited at the end of the month. You start calculating how much you will have once your income (starting from R1 = 1) is deposited into your account.

So, the instruction takes the address 1 and adds to the content of 𝑅1. So, the content of 𝑅1 and 𝑅2 both have 0. So initially both of them has 0 value so that is this 1 will be added to the content of 𝑅1.

Here, the instruction specified uses the value in R1 to calculate the effective memory address to access data. By adding 1 to the value of R1 (which is initially 1), we determine that the effective memory address to retrieve data is simply 1, which points to a specific location in memory that contains some data. Therefore, if both R1 and R2 are 0, you may consider that the memory operation would be fetching the data located at address 1.

Consider you are trying to find a book in a library. If you know that the first book is in slot 1, and that's your starting point (like R1 = 1), you would simply walk over to slot 1 to get that book. Just like accessing that book, accessing memory locations works similarly by using calculated addresses.

So, whatever will be the content will be added with 0 that is the content of R5 and it will be stored over here. Next what you will do you will increment the value of the register number 𝑅1.

Once the data from memory is retrieved, it is added to the contents of R5, which initially is 0. This operation effectively updates R5 with the retrieved data—for instance, if Memory[1] had a value of 10, then R5 will now hold the value 10 after the addition. After this, R1 is incremented, which means it will now point to memory location 2, preparing for the next operation in the sequence.

Imagine you receive the first book that is filled with interesting knowledge (value from memory). Once you've read it, you note down your insights into your journal (R5) — your journal now reflects this new knowledge. Afterwards, you move on to prepare to read the next book, hence incrementing your focus from one book to the next (updating R1 to access the next memory location).

Now it will be pointing to this next memory location that will be again loaded added with the content of R5 and stored back.

After R1 increments, it points to the next memory address. The content at this new address (let’s say Memory[2]) will now be added to the current R5 value. This process repeats where each time we read a value from memory and add it to R5, allowing R5 to accumulate values from successive memory locations as indexed by R1.

It's like reading every chapter of a book consecutively, and for each chapter, you jot down the key details in your notebook (R5). As you finish each chapter (moving sequentially through memory), you keep adding new insights to your notebook, which grows richer and covers more content as you advance through the book.

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