Speaker 1: Welcome to the deep Dive. Today. We're going to be
Speaker 1: taking a look at ARM sixty four architecture, you know,
Speaker 1: the stuff that powers a lot of our devices.
Speaker 2: It's kind of like getting it behind the scenes tour
Speaker 2: to see how the magic happens in our tech exactly.
Speaker 1: We're going to be talking about how software actually works,
Speaker 1: like going under the hood and figuring out what makes
Speaker 1: it tick.
Speaker 2: We'll be diving into memory registers, even those kind of
Speaker 2: mysterious sounding pointers. Sounds complicated, it can be, but don't worry,
Speaker 2: we'll break it all down.
Speaker 1: This deep dive is for everyone, even if you're not
Speaker 1: a programmer. It's all about understanding those fundamental building blocks
Speaker 1: because when.
Speaker 2: You understand the basics, you get a whole new appreciation
Speaker 2: for how the technology you use every day actually functions.
Speaker 1: So let's start with memory. It's basically the heart of
Speaker 1: any computer, right absolutely.
Speaker 2: One of the sources we looked at described it as
Speaker 2: a city, with each piece of data living in a
Speaker 2: house with a specific address.
Speaker 1: Okay, I can kind of see that like a giant
Speaker 1: city of data.
Speaker 2: Right, but imagine it more like a massive, well organized
Speaker 2: warehouse instead. Each piece of data has its own numbered
Speaker 2: storage unit and that number is its address.
Speaker 1: Okay, I like that a warehouse full of information, And
Speaker 1: then those addressing modes are kind of like the different
Speaker 1: ways to navigate that warehouse, right, you got it.
Speaker 2: Some modes like direct addressing are like having the exact
Speaker 2: storage unit number. Others like using offsets, are more like saying,
Speaker 2: go to aisle five, then move three units to the right.
Speaker 1: So it's all about finding the data you need quickly
Speaker 1: and efficiently.
Speaker 2: Exactly, And this is especially important when you're dealing with
Speaker 2: a lot of data or you need to access it
Speaker 2: in a specific order.
Speaker 1: It's all about optimization.
Speaker 2: You got it.
Speaker 1: Okay, that makes sense. But before we get lost in
Speaker 1: the warehouse, let's talk about those registers mentioned in the sources.
Speaker 1: Are those like a special VIP section for super important data? Uh?
Speaker 2: I like that. Analogy registers are like high speed shelves
Speaker 2: right next to the processor, the brains of the computer.
Speaker 2: They hold the data that the processor needs to access
Speaker 2: really quickly.
Speaker 1: So if our warehouse is the main memory, registers are
Speaker 1: like having a few key items right on your workbench
Speaker 1: for instant access, exactly.
Speaker 2: And with AIRM sixty four, these shelves are sixty four bits.
Speaker 1: Wide, meaning they can hold a lot more information, much.
Speaker 2: More compared to older thirty two bit systems. It's like
Speaker 2: upgrading from a handtruck to a forklift when it comes
Speaker 2: to moving data around.
Speaker 1: Okay, so that's why sixty four bit systems can feel
Speaker 1: so much faster. They're handling more information at once.
Speaker 2: That's one of the key factors. And it's not just
Speaker 2: about speed. It's also about capacity.
Speaker 1: Capacity You mean how much data it can store.
Speaker 2: Well, not exactly. It's more about how many different memory
Speaker 2: locations a sixty four bit system can access.
Speaker 1: So it's like having a map of the entire city
Speaker 1: instead of just one neighborhood.
Speaker 2: You got it, And that means sixty four bit systems
Speaker 2: are much better equipped to handle those huge, complex programs
Speaker 2: we're using today.
Speaker 1: Makes sense, but we're gonna have to save that conversation
Speaker 1: for another time.
Speaker 2: Okay, sound good.
Speaker 1: Right now, let's get back to those mysterious pointers we
Speaker 1: mentioned earlier. Those things kind of sad, like something out
Speaker 1: of a spy movie.
Speaker 2: They do, don't they?
Speaker 1: What are they really think of?
Speaker 2: Pointers like labels, each one containing the address of a
Speaker 2: specific piece of data in memory. They don't hold the
Speaker 2: data itself. They just tell you where to find it.
Speaker 1: So it's like having a treasure map that leads you
Speaker 1: to the buried treasure exactly.
Speaker 2: And pointers can be stored in regular memory or in
Speaker 2: those high speed registers we talked about.
Speaker 1: Hold on, So are you saying that pointers themselves have
Speaker 1: addresses too? That's kind of trippy.
Speaker 2: It is. A pointer is just another piece of data,
Speaker 2: so it has its own address in memory. Think of
Speaker 2: it like a library card catalog. The card has a
Speaker 2: specific spot in the catalog, but it also points you
Speaker 2: to the location of the book you're looking for.
Speaker 1: Okay, So pointers are like master organizers, creating this intricate
Speaker 1: web of interconnected data within the memory warehouse. But you
Speaker 1: mentioned earlier they can be dangerous. What did you mean
Speaker 1: by that?
Speaker 2: That's where things get really interesting, and that's exactly what
Speaker 2: we'll explore next time.
Speaker 1: All right, So we've got our memory warehouse, those speedy
Speaker 1: registers and those kind of mysterious pointers. But you said
Speaker 1: pointers can be a bit risky. Why is that.
Speaker 2: Well, it's like having a map, but you got to
Speaker 2: make sure it's the right map and you're allowed to
Speaker 2: go where.
Speaker 1: It's pointing right, Otherwise you might end up in some
Speaker 1: restricted zone exactly.
Speaker 2: And one of the biggest dangers is what we call
Speaker 2: it annul pointer. It's basically like having a map that
Speaker 2: leads to nowhere.
Speaker 1: Okay, so what happens if a program tries to use
Speaker 1: an annul pointer? Does it just get lost?
Speaker 2: It's more like hitting a wall, imagine trying to access
Speaker 2: a storage unit that doesn't even exist.
Speaker 1: So the program just crashes.
Speaker 2: Pretty much on Linux, that's usually what happens.
Speaker 1: Well, that seems like a good safety feature, like better
Speaker 1: to crash than to keep going and potentially mess things
Speaker 1: up even worse, right.
Speaker 2: You got it. The operating system is basically like Nope,
Speaker 2: not gonna let you do that, shutting you down to
Speaker 2: prevent any more damage.
Speaker 1: So it's like a security guard for our warehouse, making
Speaker 1: sure no one's snooping around where they shouldn't be.
Speaker 2: Precisely, it's all about keeping things stable and preventing data corruption.
Speaker 1: Okay, makes sense. Nul pointers are bad news. But are
Speaker 1: there other ways these pointers can go wrong? Oh?
Speaker 2: Yeah, definitely. There's a whole category called invalid pointers.
Speaker 1: So annul pointers are just one type of invalid pointer exactly.
Speaker 2: It's just one way a pointer can be invalid. Another
Speaker 2: way is if it's trying to access a part of
Speaker 2: memory that's off limits.
Speaker 1: Okay, back to our warehouse. That would be like trying
Speaker 1: to break into the vault without the right security clearance.
Speaker 2: Exactly, And just like a vault has alarms and security measures,
Speaker 2: so does the operating system. This is called an access violation.
Speaker 1: So what happens then? Does the alarm go off?
Speaker 2: Yeah? In a way, the program usually crashes, just like
Speaker 2: with an ANUL pointer.
Speaker 1: Okay, So the operating system is shutting things down to
Speaker 1: protect the integrity of the data.
Speaker 2: Exactly. It's all about maintaining order and preventing chaos in
Speaker 2: our memory warehouse.
Speaker 1: So we've got NLL pointers pointing to nothing, invalid pointers
Speaker 1: trying to break into restricted areas. Are there any other
Speaker 1: ways pointers can go rogue?
Speaker 2: There are. There's also the possibility of a pointer trying
Speaker 2: to change data that's supposed to be read only.
Speaker 1: So in our warehouse analogy, that would be like trying
Speaker 1: to scribble all over an important historical.
Speaker 2: Document, precisely, and that could lead to all sorts of problems,
Speaker 2: potentially even data corruption.
Speaker 1: Okay. So it's like you can look, but don't touch exactly.
Speaker 2: And on that note, let's talk about random pointers, which
Speaker 2: are kind of a wild card.
Speaker 1: Random pointers, what are those?
Speaker 2: They happen when a pointer hasn't been assigned to specific address.
Speaker 2: It's like grabbing a random map and just hoping for
Speaker 2: the best.
Speaker 1: You mean, it could point anywhere pretty much.
Speaker 2: Sometimes it might work out okay, but other times it
Speaker 2: can lead to crashes or other unpredictable behavior.
Speaker 1: Okay, so we got to make sure our pointers are
Speaker 1: initialized properly and pointing to the right places.
Speaker 2: Absolutely. And speaking of pointing to the right places, there's
Speaker 2: another tricky one called a dangling pointer.
Speaker 1: Dangling pointers, what makes those different?
Speaker 2: Think of it this way. You have a pointer pointing
Speaker 2: to some data. Everything's working fine, but then that data
Speaker 2: gets to or moved to a different location.
Speaker 1: Oh, so the pointer is still pointing to the old spot,
Speaker 1: but there's nothing there anymore.
Speaker 2: Exactly. It's like having a map to a building that's
Speaker 2: been demolished.
Speaker 1: And if you try to use that pointer, what happens, Well.
Speaker 2: It might seem like it's working for a while, but
Speaker 2: eventually it's going to cause problems, crashes, strange behavior, all
Speaker 2: sorts of things.
Speaker 1: Dangling pointers, random pointers, and ulel pointers in valid pointers.
Speaker 1: It sounds like there are a lot of ways for
Speaker 1: things to go wrong.
Speaker 2: There are, and that's why understanding how pointers work and
Speaker 2: how to use them safely is absolutely crucial when you're
Speaker 2: dealing with memory management.
Speaker 1: It sounds like there's a lot of power but also
Speaker 1: a lot of responsibility.
Speaker 2: Exactly, And that's actually a good segue into something else.
Speaker 2: We wanted to talk about how variables themselves can actually
Speaker 2: be used as pointers in C and C plus plus.
Speaker 1: Feel wait, hold on, variables can be pointers. I thought
Speaker 1: those were two completely different things.
Speaker 2: They are, but in those languages, a variable can actually
Speaker 2: play both roles.
Speaker 1: So it's like having a box that can hold both
Speaker 1: the treasure and the map to the treasure.
Speaker 2: That's a great way to put it, and that's part
Speaker 2: of what makes C and C plus plus so powerful
Speaker 2: and flexible. But it also means things can get a
Speaker 2: bit more complex.
Speaker 1: Okay, my brain is definitely starting to feel a little full. Here.
Speaker 1: Can you give me an example of how this works.
Speaker 2: Sure, let's take a look at a project called memory
Speaker 2: pointers that demonstrates this concept.
Speaker 1: Okay, so we're back in the warehouse and this memory
Speaker 1: pointers project shows us how variables can be used as pointers, right.
Speaker 2: Exactly, there's a part in the code where we have
Speaker 2: two regular integer variables A and B that we have
Speaker 2: two more variables, paw and p but these are pointer variables.
Speaker 2: So at the beginning, the pointer PB is set up
Speaker 2: to point to the memory location of the.
Speaker 1: Variable B, so PB is like a map that leads
Speaker 1: you straight to where B is stored.
Speaker 2: You got it. And then the code takes the pointer
Speaker 2: paw and assigns that the address of the variable A.
Speaker 1: So now both of our pointer variables paw and key
Speaker 1: are holding the addresses of A and B, right, And this.
Speaker 2: Is where things get really interesting, because now the code
Speaker 2: uses these pointers to actually change the value stored in
Speaker 2: A and B.
Speaker 1: So instead of working directly with the data itself, we're
Speaker 1: using pointers to indirectly access and modify it, kind of
Speaker 1: like a remote control exactly.
Speaker 2: For example, the code uses the notation paw to get
Speaker 2: to the value stored at the memory location pointed to by.
Speaker 1: PAW, so pause like a shortcut to get to the
Speaker 1: value of A without actually using A directly.
Speaker 2: You got it. And then the code can do things
Speaker 2: like add the values of A and B together, but
Speaker 2: it does it using the pointers.
Speaker 1: So it's still doing regular math like addition, but it's
Speaker 1: accessing the numbers through those pointers precisely.
Speaker 2: Pointers give programmers a powerful way to manage memory and
Speaker 2: manipulate data, all while working behind the scenes.
Speaker 1: Okay, so this memory pointers project is showing us how
Speaker 1: variables can do double duty. They can store data and
Speaker 1: they can also act as pointers to other data.
Speaker 2: Exactly and something you'll see a lot in ce and
Speaker 2: C plus plus plus a. It allows for some really
Speaker 2: efficient and creative ways to write code.
Speaker 1: It's like those multi tools that can be a screwdriver,
Speaker 1: a bottle opener, and a wrench all at the same time.
Speaker 2: That's a great analogy. It's all about having the right
Speaker 2: tool for the job, and pointers can be incredibly versatile.
Speaker 1: But as we've seen, there's also potential for danger if
Speaker 1: they're not used carefully.
Speaker 2: Absolutely misusing pointers can lead to all sorts of headaches,
Speaker 2: from programs crashing to those really tricky bugs that are
Speaker 2: hard to find and fix.
Speaker 1: So it seems like it takes a skilled hand to
Speaker 1: wield those pointers effectively.
Speaker 2: It does, and that's why having a good understanding of
Speaker 2: how memory works, how addresses work, and how pointers work
Speaker 2: is so important for programmers. It's the foundation for building
Speaker 2: reliable and efficient software.
Speaker 1: Now we've covered a lot of ground today, haven't we.
Speaker 1: We talked about memory registers, those mysterious pointers, how thirty
Speaker 1: two bit and sixty four bit systems work, and even
Speaker 1: how variables can be used as pointers.
Speaker 2: It's been quite a journey. Hope listeners have a new
Speaker 2: appreciation for how all of this works together to make
Speaker 2: our technology tick.
Speaker 1: I know, I've learned a ton and I'm not even
Speaker 1: a programmer. It's amazing to think about all of this
Speaker 1: complexity happening behind the scenes every time we use our devices.
Speaker 2: It really is. And remember, we've only scratched the surface here.
Speaker 2: There's so much more to learn about computer architecture, operating systems,
Speaker 2: and all the amazing things you can do with software.
Speaker 1: So keep those brains buzzin, folks. There's always more to explore.
Speaker 2: Exactly, and who knows, maybe one of our listeners will
Speaker 2: be the next brilliant mind designing the technology of the future.
Speaker 1: Well that's all the time we have for today. Thanks
Speaker 1: for joining us for this deep dive into the world
Speaker 1: of ARM sixty four. We'll be back soon with another
Speaker 1: exciting topic to explore,