Floating Point Circle Example

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Hello. This is Dr Miller, and this is Episode 8.2 of Assembly.

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Today, we're going to write a program using floating point numbers.

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So here is our program description. So we're gonna write a program to calculate the following

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the area of a circle which is pi r squared and the circumference of a circle, and then we'll have the user into those values.

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Alright, So I've already created the directory.

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So the top, we're gonna do our definitions. And so we got a few definitions we're gonna have toe put in here.

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So, for example, all enter pie,

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so we'll define it is a cue word because I don't give us more precision.

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Six.

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I give some example. Digits, you can do some. Or if you'd like to do this on your own,

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we're gonna have X, which is a value that these is gonna enter. We'll start that off zero, and that will be an imager.

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The area

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that is going to be a floating point number so we'll define it is a cured so that it has 64 bits.

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Here's our circle or circumference.

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Go ahead and to find that is also a cured zero,

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and then I'm just gonna to find the number two.

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We'll use that later.

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All right? And then we got a couple different formats. So one is for scan F.

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So I find this bites

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and then are printed format

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and then percent f is the

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formats specify air for printing off a floating point number.

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Here. We had 10 for a new line and then zero.

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We got a couple externals

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scan, huh,

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friend?

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Yes.

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All right, so now we're ready to go into our program. So first off, I have to have to add the pointer

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to the scan of format. So that is I'm gonna push X for the hat,

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push our format and then call

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scan of

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and then after that, X should have the value that we care about. So that's the number that we're going to use for our radius. I guess our might be a better term, but I'm using X.

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So because we pushed to things, we have to correct a stack.

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Okay, Now, put a comment here, so we know.

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All right.

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Next step is to load our data onto the floating point stack. So the first thing that I'm gonna do is I'm gonna go ahead and load

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pie.

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So, Ethel de Floating Point load, This is a que

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word and I'm gonna load pie.

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And then I want to multiply that by X. But X isn't manager, so f I and mole. It's a floating point imager. Mole,

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We're using a D word for X,

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so I'm pi times are times are so just go ahead and multiply again.

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Okay,

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so now I have my result. It should be on top of the stack. So I took pie and then I multiplied it and it replaced that on top of the stack.

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And so this is calculating my

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area.

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So now I need to save that

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floating point store and then p is for Pop because I don't want that to stay on the stack,

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go ahead and store that in area

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and then

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So I used pie here as

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just a number that I typed in. But there is also a floating point load high which will actually load pie on top of the stack

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and then

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so the

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the circumference is two pi r. So I've got pie, and I need to multiply that by two

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So I have my number two.

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Okay. And then I need to multiply that by X, which is our radius.

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That's also on you, ***.

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And then I need to

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Here we are

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doing that calculation,

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and then we need to store that. So we want to floating points

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store and pop.

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It's a cue word,

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and they're just telling how big. So that way it knows what to write.

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This is

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circumference.

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All right, so now comes the fun part of

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trying to print these off. So because these are Q words, I have to basically push two things onto the stack.

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So we're gonna do printing here.

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So with this, we need to I'm gonna move into the A X

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value at circumference

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plus four.

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***. I'll get me

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four of the bites and then I can push that onto the stack,

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and then I need to

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move into yea x,

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the value. It's a conference. So I gets me the other four bites.

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I don't have to push that on in the stack.

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So here we're loading

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circumference,

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and now we want to do the same thing for the area. So remember, we have to do them reverse orders. That's why we did circumference. First

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movie X area, close four.

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Push the axe,

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move yaks

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area

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without you it area,

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push the X

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And then we're gonna have to

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push our format.

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And it's called P for friends.

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And then we're gonna call print F.

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Now, if we go back, we're going to count how many things we pushed on the stack for this printing. So we got

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one. So 48 12

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16. And I missed my ex here.

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16

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in decimal, which is 10. And hex right here and then 14. Hicks. So to correct a stack, we have to do ad

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14. Add two tsp 14 hex.

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And so that's your correct a stack for all the things we

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pushed on the stack for our printing.

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Looks like I have an air. So let's go and fix that

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loading point.

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Parents post some letters there,

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and we messed one of them up. Okay, so it says area is zero conference is 6200

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so let's go back in. Double check. So

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ah, floating point store. Sea area.

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That would be a cue word.

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There we go.

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All right. So it looks like we got the right results.

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So as you can see, some of the debugging steps you have to go through and figure out which line you might have an air on

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and go and see what operation? That you might have missed type so we could see that I had a typo. I've had a couple typos.

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Um, but going through, at least the assembly will tell you that there is an air, and then he can go back and figure out where that air exists.

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So today we built our example program. And then you saw that that was used in order to

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demonstrate how we can load of floating point numbers. And then now we can print those off.

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So in the future, we're gonna talk about conditions. So making decisions based on floating point numbers.