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‫Hello and welcome, everybody, in this lecture.

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‫We're going to implement the tasks which segment, so the very first thing I want you to do is, is

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‫in our source directory, we're going to create a new directory called Task.

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‫Old task related items will go in this directory.

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‫So once again, it's in the source directory and it's called task.

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‫I'm just going to minimize all of these directories because we have quite a lot of them now.

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‫So there we go.

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‫Source directory, create new directory called Task.

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‫OK, inside this directory, we're going to create a new head, a file called DOT.

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‫Tasks, which segment, so we're going to go if and if task switch segment, page, define tasks.

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‫Which segment page?

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‫Hashtag and Jeff and I were going to create a new structure called T.S.A., so we're going to go struct

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‫tests and we're going to include Estie in it.

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‫So in a dark, guys, OK, I mean, a test structure, we're going to go Unit 32, T link, unit three,

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‫Tuti E.S.P zero.

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‫And this is the COL stack pointer.

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‫And remember, if you don't understand the test, watch the presentation again, because I explain in

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‫depth.

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‫Essentially when we go back to Col Land, the process will look into the test and it will pull out the

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‫Col stack point on the Col Stack segment and so on.

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‫So we're not going to go Unit 32 t SS zero and this is the Col Stack segment and we're going to create

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‫a lot more variables now, ones that we won't even use.

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‫But they need to be there because the process is populating this structure.

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‫So we're going to go Unit 32 T ESP one, unit 32 T, ESP two, unit three to T, SS two.

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‫Unit 32 T.

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‫S three.

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‫Unit 30 to IP Unit three, Tutsi flags, Unit 32, T X, unit 32 T X, Unit 32 T IDEX Unit 32 T SBX.

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‫Unit 32 T E.S.P.

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‫Unit 32 TBP Unit 32 T ISI Unit 32 t eddi.

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‫Unit 32 T.

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‫S.

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‫Unit 32 t c.

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‫I mean CSI Unit 32 T SS Unit thirty two t d unit 32 G F's Unit 32 T G.S. Unit 32 T LGT Unit Theta T

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‫I OPB.

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‫And we're going to pack that guys attribute packed.

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‫Perfect.

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‫So that's our team structure.

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‫We will use this to guide the process in switching the stack back to the correct state when it goes

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‫back into Col Land.

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‫OK, so let's create a new prototype here.

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‫We're going to go void to assess load in its segment and we're going to create a new file in the task

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‫directory called Test DOT HSM.

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‫We're now going to go S.A.M. Global Test Load and now we're going to go to assess load, push, SBP,

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‫Move, PSP, Move X, SBP, plus Ade's.

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‫So this is the test segment provided to us and then we're going to go LTA X Pop EBP and finally we're

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‫going to go Rets.

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‫OK, so essentially this assembly function here just loads in the tasks which segment.

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‫So it expects an integer to the test segment.

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‫So remember what I said that the S is part.

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‫Of this, you see, you have the GDP co GDP data.

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‫It's part of the GDP descriptor, essentially.

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‫OK, so the test will go somewhere in here and it will also have its own offset.

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‫So we passed that offset to the test load.

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‫OK, now, obviously, we've changed this to C-code now.

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‫So you can see that here we have three segments.

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‫OK, so would have the test somewhere here as well.

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‫OK, and the GDP real.

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‫Once we pass this through the GDP structure to GDP, the GDP will be populated with the real segments.

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‫So when we call the.

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‫TSA slowed, we pass in the segment offset for the TSA segment, and they offset we're talking about

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‫is the offset in this GDP real memory region.

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‫OK, so when I was going to go to our makefile, we're going to copy and paste this iodized HSM because

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‫we're going to use this and we're going to change the build here to task to yesterday's tomorrow on

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‫the source directory will be task tested, I assume.

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‫And then obviously we're going to assemble task TSA delays into build tasks, ITSM that I know no TSA

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‫stories and other I mean, so it should look like bad guys.

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‫And we're going to copy and paste this and we're going to put that in in our bill files at the top here.

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‫So you just paste that in there anywhere.

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‫Anywhere is fine.

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‫And we now need to go to our bill directory and we're going to create a new folder called TASC.

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‫I'm going to put a dot, keep it here because I'm using git repository, OK?

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‫And.

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‫Yes, we're now ready to try and make clean that, so let's open up the terminal.

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‫And in our in our directory here, we're going to go make clean bill to the S.H..

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‫And there we go, that that compiles perfectly fine.

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‫So, OK, back to that, see, then we're going to define a user data segment.

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‫I use a code segment.

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‫So first thing we do is put the comma here because we're making a new record in here.

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‫I want to go up a six zero zero dot limit equals zero x f f f f f and we're going to go dot type equals

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‫zero x, f eight.

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‫And put your comma here because we're going to put the data segment in the second.

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‫And this is the user code segment.

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‫And you'll notice here we map the entire address region, uh, even though the kernel also occupies

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‫this reason region because these are physical addresses.

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‫But that's absolutely fine because we're using the paging memory module.

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‫So all sorts of memory limitation will be done on paging.

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‫So here we're going to go to space equals zero zero dot limit equals zero x f f f f f dot type equals

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‫zero except two.

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‫And this will be the user

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‫data segment.

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‫And put your comma here because now we have to define the tests.

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‫So we're going to create a new one here.

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‫We're going to go to space equals and we're going to cast this because I haven't done it yet.

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‫You added 32 t ampersand to assess the address of the test variable, which we haven't created yet.

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‫And I we're going to go dot limits equals size of Texas.

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‫And we're going to go, Dotti equals zero x e nine, and this is the 26th segment.

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‫And if you're really curious about these these these bits that where we're sitting here, just look

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‫up the reference because there's not much point to explain them.

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‫Just know that it describes how this segment deals with the memory and the sorts of rights that it has

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‫and so on.

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‫If we just quickly go back to the DSM, uh.

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‫You can see, you know, the axis bites and stuff like that, right?

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‫So it just determines how this segment should manage that memory and what sort of rules should apply

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‫to it.

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‫So when are we going to create the test variable?

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‫Because we haven't created that yet.

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‫So simply put, just above GDP real, we're going to go struct success and we're going to scroll up

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‫and we're just going to include task test.

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‫OK, now that resolves that dependency and now just have to eject in it.

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‫Then we're going to load the tests.

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‫So the first thing we do is we set up the tests and we can create a new function for this later maybe.

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‫And we're just going to go said tests, zero zero zero size of tests.

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‫So that that'll just set the whole test to zero for us to make sure there's no initialize memory there.

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‫And I was just going to go to E.S.P.

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‫Zero equals zero six and we're going to have five zeros.

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‫One, two, three, four, five.

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‫So this is the kernel stack, OK?

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‫This is where the kernel stack is located.

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‫So whenever we go from user use the land back to kernel and the stack point will be changed to this.

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‫OK, and I we're going to go to SAS dot SS zero equals Peatross data selector and we haven't created

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‫that yet.

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‫And now just down here, we're going to go load the tests and we're going to go to SAS load zero x twenty

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‫eight.

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‫And the reason we use the X 28 is because that would be the offset in the GDP, in the GDP real once

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‫we pass this structure through the function.

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‫OK, so X and we're going to implement this in the conflict.

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‫Now.

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‫Oh, what do we know?

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‫We've actually already done it, we've just called the kernel data selector, so no worries.

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‫Copy that.

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‫And we're just going to paste that over.

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‫Pekoe, as stated, Selecta, a perfect let's now make clean bill that S.H..

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‫And we can see there's a slight problem here, so we're going to take a quick look at what that is.

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‫Scroll up.

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‫And yes, it's clear what the problems is the U.S. total GDP segments of three, but we now need to

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‫change it to one, two, three, four, five, six.

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‫So just change that to six.

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‫OK, and if we make clean again, so PTW total GDP segments needs to be changed to six guys, OK.

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‫And if you control left, click in Visual Studio on that definition.

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‫We will take you straight to the file.

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‫So we're going to go build that S.H. again and we see that works fine.

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‫We're going to go Sidibé and we're going to run Kumu and we can see everything works as normal.

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‫So we've now implemented the tasks which segment.

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‫So we are now ready to enter, use the land.

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‫Congratulations.