WEBVTT 00:00.390 --> 00:01.470 Hello, my name is Stephan. 00:01.470 --> 00:05.310 And in this lecture we will create our Hello World program again. 00:05.310 --> 00:08.400 But in this time we will use the make file. 00:08.700 --> 00:15.750 In previous lecture we created our Hello World program in assembly language, but without the BS section 00:15.750 --> 00:17.860 and without the make file. 00:17.880 --> 00:24.320 But in this lecture we added this to knowledge into our brains and we will start our programming. 00:24.330 --> 00:30.150 So generations of programmers have started their programming careers by learning how to display Hello 00:30.150 --> 00:31.850 World on a computer screen. 00:31.860 --> 00:39.240 It is a tradition that was started in the 70s by brain koningen In the book he wrote with Dennis Ritchie 00:39.330 --> 00:45.270 the C programming language, Cunningham developed the C programming language at Bell Labs. 00:45.270 --> 00:53.130 Since then, the C language has changed a lot, but has remained the language that every self-respecting 00:53.130 --> 00:54.930 programmer should be familiar with. 00:54.960 --> 01:01.390 The majority of modern and fancy programming languages have their roots in C, and C is sometimes called 01:01.390 --> 01:06.760 a portable assembly language, and as an aspiring assembler programmer, you should get familiar with 01:06.790 --> 01:08.560 C to honor the tradition. 01:08.560 --> 01:13.570 We will start with an assembler program to put Hello World on your screen and we will also develop the 01:13.570 --> 01:14.290 Makefile. 01:14.290 --> 01:18.610 So let's get started with developing Hello dot CSM here. 01:18.610 --> 01:25.510 So instead of writing this again, we can also um, as you can see we have three Hello world here. 01:25.510 --> 01:35.340 So erm delete, everything starts with H here and here we will open the our fasm which is the IDE or 01:35.440 --> 01:38.770 CSM and here we will create a new project. 01:38.770 --> 01:45.430 And in this new project we will save this in our assembly here. 01:46.150 --> 01:46.720 That's it. 01:46.720 --> 01:48.970 And we will name it as. 01:54.470 --> 01:55.410 Not RSM. 01:56.130 --> 01:57.000 And that's it. 01:57.120 --> 02:05.220 And here we will delete the auto generate generated code by sacem and we will add new command and we 02:05.220 --> 02:13.230 will create our Hello, SSR, ESM, and we will add a section data section data. 02:13.380 --> 02:18.300 Again, MSG, DB here again. 02:18.780 --> 02:19.440 Hello. 02:21.250 --> 02:24.100 World is okay, I think. 02:24.100 --> 02:32.440 And also we will add a null terminated string here and we will also add the section VSS and we will 02:32.440 --> 02:34.930 also create a section text. 02:34.930 --> 02:39.760 And in this lecture we will create again a global main. 02:39.760 --> 02:47.380 So if you remember, this code is different from the code we created in previous lecture and we will 02:47.380 --> 02:49.300 create our main function here. 02:49.450 --> 02:52.150 Main move here. 02:52.480 --> 02:53.350 Move. 02:55.210 --> 02:57.490 AX1. 02:57.910 --> 03:01.150 And also let's add the spaces between this. 03:03.050 --> 03:04.550 Our x one. 03:04.640 --> 03:09.110 This one corresponds for the right and move. 03:09.790 --> 03:10.510 Are. 03:14.450 --> 03:16.880 Move are the I. 03:18.230 --> 03:18.920 One. 03:18.920 --> 03:22.220 This is for the STD out. 03:24.350 --> 03:26.600 Out and we will also create the. 03:28.490 --> 03:28.820 Move. 03:30.830 --> 03:31.820 RSI. 03:32.940 --> 03:34.410 MCG here. 03:34.410 --> 03:39.510 As you can see here, we will get this variable name MCG. 03:39.750 --> 03:49.430 This is the string to display in RSA and we will also move here the RDX. 03:49.530 --> 03:54.150 This is the length of the string without the zero here. 03:54.390 --> 03:59.820 So this is the length of the string without zero. 03:59.820 --> 04:02.220 And we will call the fiscal. 04:02.370 --> 04:06.750 In this case, this fiscal will display the string on this here. 04:07.020 --> 04:08.340 Display the. 04:09.280 --> 04:11.260 Ring and move. 04:12.760 --> 04:14.830 Racks here 60. 04:14.860 --> 04:17.200 This is for exit code here. 04:17.560 --> 04:21.340 60 equals to exit and move. 04:21.550 --> 04:22.360 Ready? 04:22.960 --> 04:23.740 Zero. 04:23.740 --> 04:30.280 And this is this means the success exit code here that our program. 04:31.340 --> 04:32.870 With success here. 04:33.200 --> 04:35.630 It says exit code. 04:35.630 --> 04:38.000 And we will also add t-sql. 04:38.030 --> 04:40.040 This will quit the program. 04:43.160 --> 04:46.880 That here, this is the last line of our code. 04:47.000 --> 04:52.640 And so there are many good text editors on the market, both free and commercial. 04:52.640 --> 05:01.400 In this case, we will use CSM, which is a free and look one that supports syntax highlighting for 05:01.940 --> 05:02.630 64 bit. 05:02.630 --> 05:10.220 In this case, CSM is fully supports 64 bit and in most cases you will have to download some kind of 05:10.220 --> 05:11.420 plugin if you. 05:12.120 --> 05:16.290 Get it or uh, any other text editors to have syntax highlighting. 05:16.290 --> 05:23.010 But in, in s m the syntax highlighting come with pre-installed. 05:23.400 --> 05:28.860 And in this course we will write code for the netwide assembler here. 05:28.860 --> 05:32.310 Let's actually write this right now. 05:32.340 --> 05:37.710 Grommit np x This is for the writing things on the screen. 05:38.540 --> 05:46.040 So in this course we will write the code for Netwide assembler and. 05:46.640 --> 05:47.300 A. 05:48.110 --> 05:49.030 S. 05:49.250 --> 05:49.880 M. 05:50.780 --> 05:53.750 So there are other assemblers as well, such as. 05:53.900 --> 05:59.300 Y a s m f a s m gas or m a m from the Microsoft. 05:59.300 --> 06:05.030 And as with everything in the computer world, there are sometimes heavy discussions about which assembler 06:05.030 --> 06:14.150 is the best, and we will use an ASM in this course because it is available on Linux, Windows and Mac 06:14.150 --> 06:15.080 OS. 06:15.440 --> 06:19.970 This is available on Windows and Linux. 06:21.080 --> 06:24.670 And in Mac OS. 06:26.230 --> 06:27.940 Mac OS. 06:28.800 --> 06:31.140 And so this is one of the best. 06:32.960 --> 06:38.750 Assemblers here and RSM And because there are and also there is a. 06:38.770 --> 06:48.790 Large community using an RSM, you can find the the manual at the nasm.us and we can also use the jedit 06:48.790 --> 06:53.590 with an assembler language syntax file installed so you can find. 06:55.070 --> 06:57.980 The assembly language for the Jets as well. 06:57.980 --> 07:05.390 But in this case, as I said, M is a best idea for assembly and it's also free and open source. 07:05.390 --> 07:12.410 And here on our screen, the Hello dot Asem file is shown here. 07:12.410 --> 07:19.160 And as you can see here, we think that you will agree that syntax highlighting makes the assembler 07:19.160 --> 07:20.780 code a little bit easier to read. 07:20.780 --> 07:27.590 So when we're when we write assembly programs, we have two windows open on our screen, a windows with 07:27.590 --> 07:33.710 the IDE or text editor containing our assembler source code and the windows with a command prompt in 07:33.710 --> 07:38.450 the project directory so that we can easily switch between the editing and manipulating the project 07:38.450 --> 07:41.840 file and assembling a program, debugging and so on. 07:41.840 --> 07:45.770 And we agree that for more complex and larger project, this is not feasible. 07:45.770 --> 07:48.890 So you will need an integrated development environment. 07:48.920 --> 07:56.820 Ida But for now, working with a simple or text editor and the command line in other words, CLI will 07:56.820 --> 08:01.920 do our job and we will improve that in next lectures as well. 08:02.860 --> 08:07.090 And here we will also need the GCC for installing this. 08:07.720 --> 08:13.870 Installing GCC is one of the simplest things to do in developing assembly languages. 08:13.870 --> 08:22.120 So GCC stands for new compiler collection and this is the standard compiler and linker tool Linux. 08:22.120 --> 08:27.070 So Genius stands for it's not Unix and it's a recursive acronym. 08:27.070 --> 08:33.430 Using the recursive acronyms for naming things is an insider programmer joke that started in the 70s 08:33.430 --> 08:37.030 by Lisp programmers and the GCC. 08:37.630 --> 08:41.980 So firstly, of course we need to install GCC here. 08:41.980 --> 08:43.390 Sudo apt. 08:44.510 --> 08:46.180 Install DCC. 08:46.250 --> 08:46.730 That's it. 08:46.730 --> 08:48.590 Enter your pseudo password and that's it. 08:48.590 --> 08:49.730 As you can see, I'm installed. 08:49.730 --> 08:54.260 But now let's actually remove the DCC again. 08:54.260 --> 08:58.130 So the APT remove DCC here. 08:58.160 --> 08:59.090 Yes. 08:59.090 --> 09:02.930 So this is a pretty easy to install here. 09:06.220 --> 09:10.150 And here we will also need to use bool essential. 09:10.540 --> 09:19.180 And here now we will install the GCC again actually clear the terminal and so sudo apt install GCC. 09:19.210 --> 09:19.930 That's it. 09:19.930 --> 09:22.750 And this is easy as that. 09:22.750 --> 09:25.300 And as you can see GCC is already installed. 09:25.300 --> 09:29.920 So we will also need to install the nasm here. 09:29.920 --> 09:38.610 Sudo apt build, essential ascent shell and NSM. 09:38.680 --> 09:42.880 So actually let's actually first install it, remove our purge here. 09:42.880 --> 09:44.080 So we will remove it. 09:44.080 --> 09:49.450 As you can see, 556 disk space will be freed. 09:55.340 --> 09:56.660 And now pseudo. 09:59.920 --> 10:05.170 Sudo apt install build essential. 10:06.290 --> 10:07.760 And ask again. 10:07.760 --> 10:09.410 And as you can see here. 10:14.550 --> 10:15.120 Here. 10:16.260 --> 10:17.310 And that's it. 10:18.430 --> 10:22.780 So we have the essential and and also we have the GKE. 10:22.900 --> 10:29.170 So in order to check that, we will write GKE V here and as you can see here, using Boolean spec. 10:29.170 --> 10:37.330 So if you use if you are seeing this, this is a version Debian, then this means that GKE is installed 10:37.420 --> 10:40.360 and we will also check the V here. 10:40.360 --> 10:44.620 And as you can see in version 22.60.01. 10:44.620 --> 10:48.190 So NSM is also successfully installed. 10:48.550 --> 10:51.370 And now let's go back to our Hello World program. 10:51.370 --> 10:55.990 And this is the complete version of our code. 10:55.990 --> 11:03.850 And after that which we will create this Hello World program without the Makefile. 11:03.850 --> 11:08.560 But as a first lecture, let's create this with a. 11:09.850 --> 11:10.390 Make file. 11:10.390 --> 11:15.520 So if you click on this and as you can see, we have hello Dot Asem, if we open this with our text 11:15.520 --> 11:19.150 editor, you can see our code without syntax highlighting of course. 11:19.150 --> 11:22.780 And now we will go back to terminal here. 11:22.930 --> 11:28.030 Now we will what we will do is we will open the new file torch. 11:29.020 --> 11:31.180 Actually, let's use it with mouse pad. 11:31.570 --> 11:32.380 Mouse. 11:35.060 --> 11:45.860 Uh, so this is going to be Makefile and uh, yes, so here we will delete our old code. 11:45.860 --> 11:48.500 So this is a new file as you can see here. 11:48.890 --> 11:51.960 Clear LZ LA. 11:52.520 --> 11:55.850 Now we will open the make file here with mouse path. 11:56.990 --> 11:57.920 And that's it. 11:57.950 --> 12:00.950 Now we will write our make file here. 12:00.950 --> 12:02.810 So make file. 12:04.170 --> 12:05.340 Make file for. 12:05.340 --> 12:06.870 Hello, Esme. 12:07.140 --> 12:07.890 Hello. 12:08.400 --> 12:13.440 Here the hello all and JC all. 12:13.950 --> 12:14.820 Hello. 12:15.120 --> 12:15.510 Hello. 12:15.510 --> 12:16.230 That all? 12:16.230 --> 12:20.100 And we will also know pi argument. 12:20.100 --> 12:22.950 And after that we will use the Hello. 12:22.950 --> 12:24.390 That all here. 12:24.510 --> 12:24.870 Hello. 12:24.870 --> 12:31.640 That And after that we will with the tab here we will add an elf. 12:32.610 --> 12:36.690 For the F warfare. 12:38.070 --> 12:38.790 Hello. 12:39.790 --> 12:40.610 But Assam. 12:40.620 --> 12:44.400 And also we will create a yellow dot here. 12:44.580 --> 12:46.770 And that's it with our make file. 12:46.770 --> 12:50.090 Now we will go back and run. 12:50.100 --> 12:57.300 We will save the this file as a make file in the same directory as Hello Dot Assam. 12:57.570 --> 13:03.360 And also also after writing it, we can close the make file here. 13:03.360 --> 13:10.440 As you can see here, our make file is increased at make file and as it is our make file. 13:10.440 --> 13:11.970 And after that. 13:13.090 --> 13:13.900 Uh, we will. 13:14.430 --> 13:20.350 Um, actually, this, uh, firstly, uh, let's read the make file here, actually, and read it from 13:20.350 --> 13:20.800 here. 13:20.800 --> 13:26.310 So you read the make file from the bottom up to see what's what it is doing. 13:26.320 --> 13:28.900 So here's a simplified explanation here. 13:28.900 --> 13:33.640 So the make utility is open, the make file. 13:33.640 --> 13:35.440 So this make utility. 13:37.560 --> 13:39.200 Uh, works with a dependency tree. 13:39.210 --> 13:40.890 So it noticed that. 13:40.890 --> 13:41.510 Hello? 13:41.520 --> 13:44.190 Depends on Hello, Dot. 13:44.230 --> 13:45.710 All right. 13:45.720 --> 13:47.810 And it sees the Hello. 13:47.810 --> 13:51.310 All depends on Hello, Dot. 13:52.200 --> 13:52.830 And that. 13:52.860 --> 13:55.260 Hello, Asem depends on nothing else. 13:55.260 --> 14:01.320 So make compares the last modification date of Hello dot asem with the hello. 14:01.320 --> 14:02.250 Oh and. 14:02.250 --> 14:11.230 And if the date from hello Asem is more recent make executes the line after hello which is hello dot 14:11.280 --> 14:11.940 asem. 14:11.940 --> 14:20.130 So then make starts reading the make file and finds that the modification date of hello dot oh is more 14:20.130 --> 14:21.420 recent than the date from. 14:21.420 --> 14:21.750 Hello. 14:22.020 --> 14:22.790 Hello. 14:22.800 --> 14:25.950 So it executes the line after hello. 14:25.950 --> 14:27.340 Which is hello. 14:27.340 --> 14:33.720 Oh here and in the bottom line of our make file and is used as the assembler. 14:33.900 --> 14:41.620 So the f is followed by the output format in our case is elf64, which means executable linkable format 14:41.620 --> 14:42.820 for 64 bit. 14:42.820 --> 14:49.390 And the g means that we want to include the include the debug information in a debug format specified 14:49.390 --> 14:58.840 after the F option and we use the var debug format and the software geeks for this format seem to like 14:58.840 --> 15:02.470 The Hobbit and Lord of the Rings written by J.R.R. Tolkien. 15:02.470 --> 15:09.550 So maybe that's why they decided that the var will be a nice compliment to Elf, just in case you were 15:09.550 --> 15:10.090 wondering. 15:10.090 --> 15:13.900 So seriously, the var stands for the debug with arbitrary record format. 15:14.140 --> 15:17.080 The debug with arbitrary the record format. 15:17.710 --> 15:25.780 And stamps in another debug format here, which has nothing to do with all the stabbings in novels. 15:25.780 --> 15:29.460 So the name comes from symbol table strings we will use. 15:29.470 --> 15:33.790 We will not use the steps here so you won't get hurt here. 15:33.790 --> 15:40.000 And this l here tells NASA to generate the LST file. 15:40.150 --> 15:47.830 We will use the LST files to examine the results of the assembly, and NASA will create an object file 15:48.190 --> 15:50.140 with an dot or extension. 15:50.140 --> 15:51.880 And that object file will. 15:53.130 --> 15:56.310 What will next be used by our linker. 15:56.310 --> 16:03.780 And often it will happen that NSM complains a number of cryptic messages and refuses to give you an 16:03.780 --> 16:04.490 object file. 16:04.500 --> 16:10.980 So sometimes NSM will complain so often that it will drive you almost insane. 16:10.980 --> 16:14.480 In use cases, it is essential to keep calm. 16:14.490 --> 16:19.080 You have another coffee and review your code because you did something wrong. 16:19.110 --> 16:24.990 As you as you program more and more in assembly, you will catch mistakes faster. 16:24.990 --> 16:30.600 And when you finally convinced that NSM to give you an object file, this object file is linked with 16:30.600 --> 16:36.570 a linker and a linker takes your object code and searches the system for other files that are needed. 16:36.570 --> 16:40.980 So typically system services are or other object files as well. 16:40.980 --> 16:48.360 So these files are combined with your generated object code by the linker and then an executable file 16:48.360 --> 16:49.050 is produced. 16:49.080 --> 16:56.290 Of course, the linker will take every possible occasion to complain to you about missing things and 16:56.290 --> 16:57.010 so on. 16:57.010 --> 17:02.140 So if that is the case, have another coffee and check your code and make file as well. 17:02.140 --> 17:08.770 In our case, we use the linking functionality of GCC, as you can see here. 17:08.770 --> 17:09.040 Hello. 17:09.040 --> 17:09.310 Hello. 17:09.310 --> 17:13.060 All GCC or hello all know Pi. 17:13.090 --> 17:19.030 So there is an GCC linker and compiler generate position independent executable pis. 17:19.030 --> 17:25.840 So this is to prevent hackers from investigating how memory is used by a program and eventually interfering 17:25.840 --> 17:27.310 with a program execution. 17:27.310 --> 17:32.320 And at this point we will not build a position, independent executables, and it will really complicate 17:32.320 --> 17:36.430 the analysis of our program on purpose for security reasons. 17:36.520 --> 17:40.570 So we added the parameter no Pi in the make file. 17:40.570 --> 17:47.770 And finally, you can insert commands in your Makefile by preceding them with the this hashtag symbols 17:47.770 --> 17:54.970 as we did in first line here, make file for location and we use GCC because of the ease of accessing 17:54.990 --> 17:58.240 C standard library functions from within the assembler code. 17:58.240 --> 18:04.780 And to make life easy we will use C language functions from time to time to simplify the example assembly 18:04.780 --> 18:05.620 code as well. 18:05.620 --> 18:12.340 So just, you know, another popular linker on Linux is LD the linker. 18:13.290 --> 18:17.290 And if the previous paragraphs do not make sense to you, don't worry. 18:17.310 --> 18:18.360 Have a copy. 18:18.390 --> 18:20.140 Copy and carry on. 18:20.160 --> 18:21.180 It is just a background. 18:22.460 --> 18:24.020 Important at this stage. 18:24.200 --> 18:29.510 And here at the command prompt here, we will go back to here. 18:29.510 --> 18:36.380 Let's actually close this and we will go to the directory where you saved our Hello ESM file and your 18:36.380 --> 18:37.070 make file. 18:37.070 --> 18:40.880 In this case, we are in this directory so we won't go anywhere. 18:40.880 --> 18:48.110 So we will type make to assemble and build the program and then run the program by typing. 18:48.110 --> 18:48.470 Hello. 18:48.470 --> 18:51.950 So as you can see, we could Hello here and. 18:52.970 --> 18:58.250 If you see the message Hello world displayed in this screen here. 18:58.280 --> 18:58.940 I'm sorry. 18:59.240 --> 18:59.460 Hello? 18:59.480 --> 19:01.990 With two L and that's it. 19:02.000 --> 19:02.810 Our program works. 19:02.810 --> 19:08.630 So if you see the message Hello world displayed in front of the command prompt, then everything worked 19:08.630 --> 19:09.440 out fine. 19:09.470 --> 19:14.960 Otherwise you made something typing or other error and you need review your source code or mac file. 19:14.960 --> 19:20.000 So refill your cup of coffee and happy debugging.