23.1. Vertical and Horizontal Micro-Programs

So, whenever we want to optimize based on encoding or compressing of the signals in each of these cells or each of the words in the program control memory, we call it as a vertical micro-program.

Vertical micro-programming focuses on optimizing the storage of signals in program control memory by encoding or compressing data. This method reduces the number of bits required for each signal, enhancing memory efficiency.

Think of vertical micro-programming like packing a suitcase. Instead of haphazardly throwing items in, you carefully fold clothes and utilize every inch of space, ensuring you can fit more into the same size suitcase.

In horizontal it is very flat and no optimization is there. So now, what way you can do the only way you can do is you have to encode encoded by many way xyz.

Horizontal micro-programming is characterized by its flat structure, where no compression or encoding is applied. Each control signal is distinct and takes up space independently, leading to less efficient memory usage compared to vertical micro-programming.

Horizontal micro-programming can be likened to a messy room where everything is out in the open—books scattered, clothes unfolded, and items taking up unnecessary space. You can see everything, but it takes up more room than needed.

So, whenever we want to optimize on sparse values of a matrix there is only one way to do it we have to encode it.

In vertical micro-programming, various encoding techniques are utilized to handle sparse values in matrices efficiently, reducing the number of bits required. By representing data in a compact format, this approach saves memory and enhances performance.

Consider encoding like using abbreviations in text messages. Instead of writing 'see you later,' you might write 'CUL8R'. This saves space and makes communication more efficient.

So, basically first the most formal or the preliminary way of doing it is basically encode the signals in the control memory.

A crucial aspect of vertical micro-programming is the use of a decoder, which translates encoded signals back into actionable control signals. This step is essential for executing commands based on the encoded data stored in memory.

Think of the decoder like a translator. If you write a message in a code that only you understand, you will need someone to decode it back into plain language for others to understand. Similarly, the decoder translates encoded signals back to control commands.

So now, you have to observe that this is one of the drastic way of compressing. So, instead of 2^n the size will just become n or if it is n you will go for log n upper ceiling.

Vertical micro-programming drastically reduces memory size requirements. When compared to traditional memory structures, decompression transforms a scenario that typically requires 2^n bits into just n bits or log n bits, optimizing space.

This can be compared to digital images. High-resolution images can take up a lot of space, but when compressed, they can fit much more information into the same storage, retaining quality while using less memory.

But, the problem is that at any point of time only one of these signals can be made 1.

A significant drawback of vertical micro-programming is its limitation to activate only one signal at a time. This sequential activation can slow down processing since multiple signals required for simultaneous operations must be handled in separate steps.

Imagine a single-lane bridge that can only allow one car to pass at a time. While this may be efficient in reducing congestion on the bridge, it ultimately slows down the overall traffic flow.

So, if we have a lot of 0s then such problems will become in such some kinds of number of stages will be less,... So, the time steps will increase, but this vertical micro-program advantage comes because, they are all lots of 0s and therefore, only we go for the vertical technique.

Vertical micro-programming offers the advantage of reduced memory usage, especially when many control signals may be '0'. However, the downside is necessitating more time steps for execution, as only a single signal can be '1' at a time. This leads to longer overall processing time compared to the faster, fully parallel approach of horizontal micro-programming.

Consider cooking versus meal prep. Meal prep (vertical) saves time overall but might require more steps (more time) to prepare each dish separately. In contrast, cooking everything at once (horizontal) is faster but less efficient in terms of kitchen space.

So, what I do? I actually make a cluster 2 clusters. In 1 cluster I will put the 𝑃𝐶, in another cluster actually I will put memory address register in.

The hybrid approach combines elements of both vertical and horizontal micro-programming. By clustering control signals that can be activated simultaneously, this method allows for greater flexibility and faster processing, while still benefiting from certain compressive advantages of vertical micro-programming.

Imagine a team project where some members work on different tasks that can be done simultaneously. By dividing into two smaller groups (clusters), you complete the project faster while still focusing on optimizing individual contributions in each group.

So, consolidating what we have discussed, in horizontal micro-program less number of micro instructions are required. It’s a fully parallel architecture no encodings, extremely fast...

To summarize, horizontal micro-programming is efficient for speed and simplicity, requiring fewer instructions and allowing parallel processing. In contrast, vertical micro-programming emphasizes memory efficiency through compression techniques at the cost of speed. The hybrid approach seeks to balance the benefits of both methods, providing efficiency without sacrificing too much speed.

Think of horizontal micro-programming as a high-performance sports car, fast but requires lots of fuel (memory). Vertical micro-programming, on the other hand, is like a hybrid car—more efficient with fuel but may not go as fast. The hybrid approach in micro-programming is akin to a well-tuned car that balances speed and efficiency.

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