1 00:00:00,180 --> 00:00:01,180 ‫Hello and welcome. 2 00:00:01,200 --> 00:00:08,640 ‫And in this election year, we're going to further implement the keyboard, we're going to receive keyboard 3 00:00:08,640 --> 00:00:17,370 ‫interests from the two keyboard driver, and we are then going to use the keyboard push function to 4 00:00:17,370 --> 00:00:21,990 ‫push the keys that will press to the keyboard buffa of the running process. 5 00:00:22,210 --> 00:00:26,580 ‫Once this is implemented correctly, it should be pretty simple for us to type keys on the keyboard 6 00:00:26,880 --> 00:00:33,900 ‫and they will be pushed into the process as keyboard buffa ready for that process, his task to pop 7 00:00:33,900 --> 00:00:34,170 ‫them. 8 00:00:34,690 --> 00:00:45,540 ‫OK, so yes, let's begin go to classic stage and we're just going to go define classic keyboard key 9 00:00:45,540 --> 00:00:47,810 ‫released zero eight. 10 00:00:47,820 --> 00:00:49,530 ‫Now this is a bit massive, OK? 11 00:00:50,190 --> 00:00:54,030 ‫The scan code also has a bit mask applied to it. 12 00:00:54,150 --> 00:00:58,590 ‫So let us know certain things, such as if the key was released or not and we need to take that into 13 00:00:58,590 --> 00:00:59,100 ‫account. 14 00:00:59,430 --> 00:01:05,190 ‫So now we go define Finisar keyboard interrupt and that is zero twenty one. 15 00:01:05,460 --> 00:01:12,930 ‫OK, back to Classic Tazi and we'll begin implementing our keyboard interop Tandler. 16 00:01:13,590 --> 00:01:19,530 ‫OK, so this classic keyboard handle function will be called from our internal handler. 17 00:01:19,530 --> 00:01:26,340 ‫We haven't created that yet, but let's just stop filling in this function and we'll do that a bit later. 18 00:01:26,640 --> 00:01:29,490 ‫So the very first thing we need to do is switch to the kernel page. 19 00:01:29,910 --> 00:01:33,630 ‫So just include kernel that at the top here, guys. 20 00:01:33,810 --> 00:01:39,890 ‫OK, we're also going to want to include it, the Hajj as well, guys. 21 00:01:39,900 --> 00:01:43,350 ‫OK, scroll back down. 22 00:01:43,350 --> 00:01:45,540 ‫We see Colonel Page now works fine. 23 00:01:46,200 --> 00:01:47,760 ‫We're going to go unit eighty. 24 00:01:48,000 --> 00:01:49,680 ‫Scan code equals zero. 25 00:01:50,280 --> 00:01:59,580 ‫Scan code equals Ehnes be keyboard input port and we haven't defined that yet. 26 00:01:59,580 --> 00:02:01,020 ‫Will define that shortly. 27 00:02:01,290 --> 00:02:05,250 ‫And we can also end up with a rogue IQ also sent to us. 28 00:02:06,030 --> 00:02:07,530 ‫So we should just ignore that one. 29 00:02:07,530 --> 00:02:12,810 ‫OK, so we ignore that one by just reading from the keyboard part once again. 30 00:02:14,280 --> 00:02:18,510 ‫Sometimes it sends other information that we don't really care about so much. 31 00:02:18,840 --> 00:02:21,150 ‫So this one reads the scan code. 32 00:02:21,150 --> 00:02:24,500 ‫This one ignores the rogue byte sent to us after that. 33 00:02:25,050 --> 00:02:32,430 ‫OK, go back, go back to classic Hajj and we're just going to go hashtag define keyboard input part 34 00:02:33,210 --> 00:02:34,380 ‫060. 35 00:02:34,830 --> 00:02:39,050 ‫OK, now these are parts we can read from on the bus, OK. 36 00:02:39,060 --> 00:02:43,770 ‫And 060 is responsible for letting us know which keys were pressed. 37 00:02:43,770 --> 00:02:51,060 ‫OK, now if I just go to Firefox, I can show you this a little better. 38 00:02:53,180 --> 00:02:57,700 ‫So I'm just going to go across 60 parts, OK? 39 00:02:59,830 --> 00:03:02,620 ‫OK, so it's this article here. 40 00:03:03,220 --> 00:03:10,410 ‫We were already on it signing a search for Zywiec 16 here, so you can see the power to control itself, 41 00:03:10,410 --> 00:03:13,620 ‫uses iReports CEREC 16 06, six for. 42 00:03:14,630 --> 00:03:19,920 ‫OK, so that's why we're reading from zero to 60, because that's the data part. 43 00:03:20,070 --> 00:03:22,630 ‫OK, that's why we're doing that. 44 00:03:23,270 --> 00:03:28,580 ‫So this part is where those keys to oppressed are sent to us. 45 00:03:28,580 --> 00:03:31,830 ‫And so we need to read from that part on the bus. 46 00:03:31,850 --> 00:03:34,130 ‫OK, so brilliant. 47 00:03:34,130 --> 00:03:39,320 ‫At this point, online 57, we have the scan code that was pressed on the keyboard. 48 00:03:39,680 --> 00:03:40,330 ‫Perfect. 49 00:03:40,880 --> 00:03:43,380 ‫We now to convert that to a character. 50 00:03:43,610 --> 00:03:46,670 ‫Well, we made that function here a few lectures ago. 51 00:03:46,670 --> 00:03:48,170 ‫Classic keyboard scan code to. 52 00:03:48,950 --> 00:03:51,920 ‫OK, so the first thing we need to do is check if the key was released. 53 00:03:51,940 --> 00:04:01,180 ‫So how do we do that is we say if scanned code ampersand, classic keyboard key released. 54 00:04:01,940 --> 00:04:06,460 ‫OK, so if this bit is set in the scanned code, then the key was released. 55 00:04:06,470 --> 00:04:11,750 ‫OK, and if the key was released, we're just going to return because we don't want to handle any key 56 00:04:11,750 --> 00:04:13,400 ‫releases at this point in time. 57 00:04:13,490 --> 00:04:16,840 ‫We don't care if they release the key or not. 58 00:04:16,850 --> 00:04:18,400 ‫We only care if they press the key. 59 00:04:18,410 --> 00:04:21,470 ‫OK, we can worry about key releases another time. 60 00:04:22,220 --> 00:04:25,100 ‫But anyway, so yeah, we return if that bit is set. 61 00:04:25,100 --> 00:04:25,930 ‫OK, brilliant. 62 00:04:26,260 --> 00:04:35,480 ‫So now here we're going to go unit 80 C equals classic keyboard scan code to CHA and we're going to 63 00:04:35,480 --> 00:04:36,800 ‫pass in the scan code here. 64 00:04:36,800 --> 00:04:42,740 ‫OK, and if the C does not equal zero, then we have a character in the Bufford and if the character 65 00:04:42,740 --> 00:04:49,610 ‫is not equal to zero, then we have a valid scan code that that that is being converted to an ASCII 66 00:04:49,610 --> 00:04:50,160 ‫character. 67 00:04:50,180 --> 00:04:52,670 ‫OK, and we can push that to the keyboard. 68 00:04:52,670 --> 00:04:57,410 ‫So we go keyboard push, see, OK, like that. 69 00:04:58,130 --> 00:05:03,360 ‫And that will push the character to the keyboard buffer of the current process. 70 00:05:03,830 --> 00:05:11,760 ‫OK, we now need to switch back to the task page and that is it for the classic keyboard handle interrupt. 71 00:05:11,960 --> 00:05:15,020 ‫So if we scroll down now, it's a classic keyboard in it. 72 00:05:16,200 --> 00:05:17,300 ‫Uh, scroll up. 73 00:05:17,300 --> 00:05:27,050 ‫I mean by here we now need to register the callback, so we're just going to go ADT register in callback 74 00:05:27,650 --> 00:05:33,230 ‫and we're going to use the ISO keyboard and SREP, which is Xerox twenty one and we're going to have 75 00:05:33,230 --> 00:05:38,480 ‫the function, the classic keyboard handle interrupts. 76 00:05:40,160 --> 00:05:46,850 ‫OK, and if we scroll down to that classic keyboard handle and just copy and paste this prototype, 77 00:05:47,730 --> 00:05:51,170 ‫OK, just copy and paste it above there so it can resolve it. 78 00:05:52,160 --> 00:05:56,330 ‫And you can see a little spelling mistake here, but a second s here. 79 00:05:56,360 --> 00:05:57,830 ‫OK, and scroll down. 80 00:06:00,300 --> 00:06:05,830 ‫Because we also made the mistake with this function here, so just correct that it should say classic 81 00:06:05,830 --> 00:06:07,230 ‫guys like classic. 82 00:06:09,110 --> 00:06:12,510 ‫Like that, OK, classic keyboard handle interrupt. 83 00:06:14,120 --> 00:06:15,210 ‫OK, perfect. 84 00:06:15,680 --> 00:06:23,630 ‫So now that we have registered that intro, Tangela, we should now be able to handle keyboard key presses, 85 00:06:23,630 --> 00:06:29,990 ‫OK, when we press a key on the keyboard, that should cause the interruption to be to be invoked 621, 86 00:06:30,500 --> 00:06:35,690 ‫which will lead to our classic keyboard handle interop function being run, we should then be able to 87 00:06:35,690 --> 00:06:37,100 ‫extract the schang code. 88 00:06:37,700 --> 00:06:43,610 ‫And if the key was was not released, i.e. they pressed it, it wasn't just a release. 89 00:06:43,850 --> 00:06:45,970 ‫We don't care for release events basically. 90 00:06:45,980 --> 00:06:54,350 ‫OK, so if it was only press then it will convert the Chanko to a char and then push that to the buffer. 91 00:06:54,360 --> 00:06:55,510 ‫Let's see if this works then. 92 00:06:55,520 --> 00:06:58,790 ‫OK, so we're going to go make clean build that S.H.. 93 00:07:00,480 --> 00:07:06,540 ‫And we can see implicit declaration of TASC Page, that's no big deal, scroll up, we're going to need 94 00:07:06,540 --> 00:07:08,280 ‫to include tests Hajj. 95 00:07:08,880 --> 00:07:11,160 ‫OK, just like that. 96 00:07:12,270 --> 00:07:13,200 ‫We try that now. 97 00:07:15,630 --> 00:07:20,130 ‫We can see that compiles absolutely fine, and if we just run that for a second. 98 00:07:23,690 --> 00:07:31,130 ‫Yeah, we can see that that is working all OK, so we're about to debug this now and check if the key 99 00:07:31,130 --> 00:07:33,290 ‫press is handled correctly. 100 00:07:34,070 --> 00:07:35,670 ‫But before we do that, go to Canada. 101 00:07:35,670 --> 00:07:38,550 ‫Let's see, because we're going to remove that time in time. 102 00:07:38,630 --> 00:07:44,270 ‫Call back we made so you can see here, we said it registered your callback 620 time, but just get 103 00:07:44,270 --> 00:07:45,830 ‫rid of that, OK? 104 00:07:46,160 --> 00:07:47,480 ‫And scroll up. 105 00:07:47,480 --> 00:07:50,180 ‫And you will also notice I passed an interim frame here. 106 00:07:50,510 --> 00:07:52,490 ‫This was an unfortunate mistake. 107 00:07:53,330 --> 00:08:01,690 ‫If we go to I see that you can see that the prototype takes no arguments for callbacks, OK? 108 00:08:01,950 --> 00:08:07,580 ‫Nevertheless, we passed a function with an interim frame and obviously it's not passing as an interim 109 00:08:07,580 --> 00:08:07,940 ‫frame. 110 00:08:08,240 --> 00:08:11,450 ‫So this is an initialized point one one. 111 00:08:11,720 --> 00:08:14,480 ‫The interim calls pick a time a callback. 112 00:08:14,480 --> 00:08:17,480 ‫OK, so what it should have been is that OK? 113 00:08:17,480 --> 00:08:21,860 ‫Just to let you know that it's no big deal because it was just for testing purposes. 114 00:08:22,310 --> 00:08:25,600 ‫But yeah, minor mistake that that's all. 115 00:08:26,180 --> 00:08:31,460 ‫Just delete this function because we don't need that anymore because we've removed the the actual callback, 116 00:08:32,870 --> 00:08:36,050 ‫the registration of the callback, we've removed that. 117 00:08:36,060 --> 00:08:37,330 ‫So just go to that function. 118 00:08:37,690 --> 00:08:40,190 ‫OK, now we have a nice blank slate to work with. 119 00:08:40,820 --> 00:08:45,320 ‫Let's just build again and then we will go to GDB. 120 00:08:46,940 --> 00:08:57,200 ‫So now we're just going to go CDB and GDB, add Simbo file build kind of 4.0 06 one one, two, three, 121 00:08:57,200 --> 00:08:58,010 ‫four, five. 122 00:09:00,350 --> 00:09:08,060 ‫And we're just going to scroll up to Classic Tazi and we're going to put a breakpoint on classic keyboard 123 00:09:08,060 --> 00:09:09,700 ‫handle interrupts to just go break. 124 00:09:10,190 --> 00:09:16,640 ‫Classic keyboard handle interrupt and we're going to now stop the emulator. 125 00:09:24,860 --> 00:09:31,220 ‫And I would just kind see to continue and we can see here there was a little bug launch in the emulator 126 00:09:32,120 --> 00:09:33,260 ‫since the program started running. 127 00:09:33,270 --> 00:09:37,820 ‫So just close the emulator if that happened to you, and just run that command again. 128 00:09:38,630 --> 00:09:39,950 ‫And that we are we can see that works. 129 00:09:39,950 --> 00:09:40,540 ‫OK, now. 130 00:09:40,910 --> 00:09:42,920 ‫So now just pressie to continue. 131 00:09:43,910 --> 00:09:48,590 ‫OK, press any key whilst you're on kumu and there we go. 132 00:09:48,600 --> 00:09:56,090 ‫I pressed a and you can see the classic keyboard handles interrupt routine was called if I just go next 133 00:09:56,600 --> 00:09:58,670 ‫next next next. 134 00:09:59,420 --> 00:10:01,160 ‫If I print the scan code here. 135 00:10:05,020 --> 00:10:11,140 ‫And we can see we lost our way here, that's because in speeches, an assembly instruction and because 136 00:10:11,140 --> 00:10:17,530 ‫it doesn't have line information, it's caused our emulator here debugger, I should say, to make a 137 00:10:17,530 --> 00:10:18,430 ‫little mistake here. 138 00:10:18,440 --> 00:10:26,470 ‫So we're going to have to go layaways and just just go step by step by step by step by step by until 139 00:10:26,470 --> 00:10:27,940 ‫we're back and now we're back. 140 00:10:27,940 --> 00:10:32,790 ‫We can go layo prev like that, which will take us back to the CAVU. 141 00:10:33,490 --> 00:10:38,590 ‫OK, so we're going to go next and we scan code now we can see that's 30. 142 00:10:39,100 --> 00:10:41,730 ‫OK, because I pressed a it might be something different for you. 143 00:10:41,740 --> 00:10:53,140 ‫OK, now I'm going to go break source keyboard classic dot c line sixty nine. 144 00:10:54,250 --> 00:10:55,060 ‫I see. 145 00:10:56,420 --> 00:11:00,590 ‫And I go next, I have to go princi and what do we see, we see a. 146 00:11:01,330 --> 00:11:07,670 ‫So the colonel completely knows that I pressed the character a so well done. 147 00:11:07,690 --> 00:11:13,810 ‫You've now actually created your very first keyboard driver and we can see if we go next. 148 00:11:14,920 --> 00:11:19,260 ‫That pushes the character was press to our processes keyboard. 149 00:11:19,630 --> 00:11:27,130 ‫So we step into that next, next, next we can see the processes there. 150 00:11:28,090 --> 00:11:31,120 ‫OK, perfect. 151 00:11:31,730 --> 00:11:41,650 ‫And if we now go next, next we can see that the keyboard buffer now contains a do print process. 152 00:11:41,650 --> 00:11:48,250 ‫We can see two ways because we printed one in kernel that C which I forgot to remove a good candidate 153 00:11:48,250 --> 00:11:51,280 ‫c c the key will push the example. 154 00:11:51,280 --> 00:11:52,260 ‫We did get rid of it. 155 00:11:52,840 --> 00:12:00,230 ‫OK, we don't want that because that's pushing characters that were never pressed to the keyboard before. 156 00:12:00,400 --> 00:12:01,690 ‫Emulating a key press. 157 00:12:01,690 --> 00:12:02,920 ‫I suppose so. 158 00:12:02,920 --> 00:12:03,070 ‫Yeah. 159 00:12:03,070 --> 00:12:05,020 ‫We can see the buffer contains two ways. 160 00:12:05,290 --> 00:12:10,630 ‫Well because the kernel that c we push there and also because they pressed A on the keyboard. 161 00:12:11,170 --> 00:12:12,640 ‫So that's really, really good guys. 162 00:12:12,640 --> 00:12:13,210 ‫Well done. 163 00:12:13,210 --> 00:12:19,020 ‫And if we now go C to continue again, go back to commute press, any other key will go for Z. 164 00:12:19,030 --> 00:12:21,760 ‫I'm going to go for Z and I'll press C to continue. 165 00:12:22,180 --> 00:12:26,410 ‫I'm going to go next princi and what we see there Z was press. 166 00:12:26,800 --> 00:12:28,390 ‫OK, so congratulations. 167 00:12:28,390 --> 00:12:30,430 ‫You've just implemented the keyboard. 168 00:12:31,210 --> 00:12:35,320 ‫Now how do we get the user process to interact with the keyboard. 169 00:12:35,980 --> 00:12:37,660 ‫OK, well this is fairly simple. 170 00:12:37,660 --> 00:12:38,110 ‫All right. 171 00:12:38,830 --> 00:12:42,310 ‫We create a kernel command for popping from the keyboard, OK? 172 00:12:42,850 --> 00:12:48,820 ‫And then in a user program we'll have a while loop where it's constantly popping from the keyboard. 173 00:12:49,120 --> 00:12:51,580 ‫And if it's not zero, then a key was pressed. 174 00:12:51,940 --> 00:12:55,150 ‫If a key was pressed, it can output it to the terminal for us. 175 00:12:55,870 --> 00:13:02,890 ‫So in the next few lectures, we'll be creating the ability to push to push characters to the terminal 176 00:13:02,890 --> 00:13:07,780 ‫and also popping from the keyboard, OK, which will allow people to enter text. 177 00:13:08,530 --> 00:13:10,450 ‫So thanks so much for watching this lecture. 178 00:13:10,450 --> 00:13:13,180 ‫You now have the keyboard drive implemented. 179 00:13:14,050 --> 00:13:17,140 ‫Granted, it doesn't support caps lock or anything like that. 180 00:13:17,380 --> 00:13:19,480 ‫Everything you type will be in uppercase. 181 00:13:20,320 --> 00:13:26,500 ‫We can worry about implementing case sensitivity later on and listening to the caps lock and so on. 182 00:13:27,160 --> 00:13:28,870 ‫These things can come later. 183 00:13:29,080 --> 00:13:32,410 ‫Let's just get it so you can actually type something on the terminal first. 184 00:13:32,710 --> 00:13:34,030 ‫So thanks so much for watching.