WEBVTT 00:00.310 --> 00:01.990 And now that's it. 00:02.110 --> 00:05.600 We have completed our program and it's running, as you can see. 00:05.650 --> 00:09.820 We just have some like, uh, three typos here. 00:10.210 --> 00:16.190 As you can see here in line 7109 and 135. 00:16.210 --> 00:17.410 So I already fix that. 00:17.410 --> 00:21.120 And just the regular typos here like a. 00:22.490 --> 00:28.730 Are as all Thai here, like the 1 or 2 keyword typos I fixed it with here. 00:28.730 --> 00:29.570 Now it's fixed. 00:29.570 --> 00:30.950 As you can see, it's running. 00:30.980 --> 00:33.230 I also, uh, the. 00:34.360 --> 00:36.070 Publish the fixed one here. 00:36.070 --> 00:37.410 That is not a big deal. 00:37.420 --> 00:44.650 Now, in this lecture, what you're going to learn is you will learn all of the registers and the. 00:45.650 --> 00:50.210 I will explain all of the things that we did in this code here. 00:50.210 --> 00:55.100 And as you can see, it's almost 150 lines of code. 00:55.280 --> 00:56.300 So. 00:57.580 --> 01:01.750 Now let's start from the assembly. 01:04.610 --> 01:10.790 The start from the increment here because we already explained the previously code. 01:10.820 --> 01:13.010 Here before the increment. 01:14.790 --> 01:16.710 So here we have increment, right? 01:16.710 --> 01:17.490 So. 01:18.680 --> 01:21.860 We are using the as a first assembly here. 01:21.860 --> 01:24.740 We are using the this instruction here. 01:24.740 --> 01:30.650 This instruction moves the value stored in the memory location referred as number one into the Rax register 01:30.650 --> 01:35.270 and it's loading the value of number one into the register for manipulation. 01:35.270 --> 01:41.150 And I see here this is the instruction here. 01:41.180 --> 01:48.380 This increments the value in the rax register by one, and in this case it's incrementing the value 01:48.380 --> 01:50.450 of number one by one. 01:50.450 --> 01:56.060 Here, as you can see here, it was 1 to 8 and now it's 129. 01:56.060 --> 01:56.630 Right. 01:56.720 --> 02:04.250 And here we also have move result i rax this is this instruction moves the value in the rax register 02:04.250 --> 02:11.690 which now holds the incremented value to the memory location pointed to by result i and it stores the 02:11.690 --> 02:13.940 result of increment operation. 02:14.120 --> 02:17.750 And here we are displaying the results in this case. 02:17.870 --> 02:18.720 So. 02:19.760 --> 02:26.330 The RDA register is loaded with the memory address of the format string fmt integer. 02:26.330 --> 02:32.510 So this string will be used in the printf function to format the output. 02:32.630 --> 02:38.090 And we also have the RSI and C here in C. 02:38.480 --> 02:43.940 So this RSI register is loaded with the memory address of the message string in C here. 02:43.940 --> 02:50.600 So this message will be used in the printf function to provide context for the displayed result. 02:50.600 --> 02:52.640 I want to also here. 03:00.510 --> 03:01.530 As you can see, it's tradition. 03:01.530 --> 03:02.700 Number one, incremented. 03:03.630 --> 03:08.840 And also we have move the result. 03:08.890 --> 03:14.970 I hear the RDX register is loaded with the value stored in the memory location pointed to by result 03:15.000 --> 03:15.180 I. 03:15.210 --> 03:22.140 So this value represents the result of the incremented operation increment operation and we have the 03:22.140 --> 03:31.440 move rax and this instruction sets the value of Rax register to zero and it prepares Rax to be used 03:31.440 --> 03:36.750 as the return value when the printf function call is complete. 03:36.750 --> 03:42.420 And this instruction calls the printf function to display the formatted message and the arguments for 03:42.420 --> 03:48.870 the printed functions are loaded into the RTI, RSI and RDX registers. 03:48.870 --> 03:52.710 And we also have the incrementing here. 03:52.710 --> 03:58.980 So similar to before, this instruction moves the value stored in memory location reference by number 03:58.980 --> 04:05.470 one into the Rax register and it's loading the value of number one into the register for manipulation. 04:05.470 --> 04:10.630 And we have the D a C here. 04:11.760 --> 04:18.390 So the the the instruction decrements the value in the rax register by one. 04:18.390 --> 04:23.220 And in this case it's decrementing the value of number one. 04:23.670 --> 04:30.510 And we lastly, we have the result i rax mov result i rax this instruction moves the value in the rax 04:30.510 --> 04:38.070 register register which now holds the decremented value to the memory location pointed to by result 04:38.100 --> 04:42.570 i and it stores the IT stores the result of the decrement operation. 04:42.570 --> 04:45.600 And now we have the displaying the result. 04:45.720 --> 04:46.410 So. 04:47.310 --> 04:55.260 This is basically almost the same as the previous incrementing operation here. 04:56.830 --> 05:01.300 And yeah, the code goes same and same here. 05:01.300 --> 05:06.460 Just changing three registers, instructions and variables. 05:06.460 --> 05:08.440 But the code structure is almost the same. 05:08.440 --> 05:13.330 But here we have the in the display result divide. 05:13.330 --> 05:23.380 And now here we in the shifting code side of the code, we have something interesting here which I will 05:23.380 --> 05:25.840 explain that here. 05:25.840 --> 05:33.070 But we have SA and as a register and sal, we should have somewhere here. 05:34.330 --> 05:35.080 Not division. 05:37.730 --> 05:38.320 Sal. 05:39.770 --> 05:40.550 So. 05:41.940 --> 05:50.640 This instruction moves the value stored in the memory location referenced by a number one into the Rax 05:50.640 --> 05:55.140 register, and it's loading the value of number one into the register for manipulation. 05:55.140 --> 05:58.440 And here we have Sal rax two. 05:58.470 --> 06:09.750 The Sal instruction, also known as c h l this which is meaning the show shift logical shift logical 06:09.750 --> 06:16.770 left shifts the bits of the rax register to the left by two positions, effectively multiplying the 06:16.770 --> 06:19.080 value by two. 06:19.500 --> 06:22.230 And we have the move here. 06:22.260 --> 06:28.890 This instruction moves the value in the tax register which now holds the shifted value to the memory 06:28.890 --> 06:35.610 location pointed to by result I and it stores the result of the left shift operation. 06:36.900 --> 06:41.930 And we us what we have here, we are displaying the result with as we always do. 06:41.940 --> 06:44.280 This is the opposite, opposite for this. 06:44.310 --> 06:44.940 Here we are. 06:44.940 --> 06:49.320 Instead of using Sal, we are using a here. 06:50.530 --> 06:51.280 And. 06:56.250 --> 06:59.880 Yeah, that's it with our program explanation here. 07:01.750 --> 07:05.830 And in next lecture, we will also run this program here. 07:06.340 --> 07:08.080 Explain it, uh, deeper. 07:08.080 --> 07:10.390 And we will analyze this program as well. 07:11.190 --> 07:17.430 And before the closing, stopping this lecture, I want to explain the. 07:18.510 --> 07:19.470 Registers as well. 07:19.470 --> 07:23.430 Again, because we need to repeat it until we. 07:24.710 --> 07:25.610 Know it better. 07:25.610 --> 07:29.090 And I will start with R.D. here. 07:29.090 --> 07:35.000 So this is a general purpose registers often used to hold the address of the format string to be used 07:35.000 --> 07:37.010 with the printf function. 07:37.010 --> 07:41.420 And it is one one of the arguments passed to the functions. 07:41.420 --> 07:42.980 And we also have RSI. 07:43.280 --> 07:47.420 This is a general purpose register also used for holding arguments to function. 07:47.420 --> 07:54.140 And in the code it's utilized to hold the values of numbers or messages that need to be displayed. 07:54.140 --> 07:55.900 And we also have RDX. 07:55.910 --> 08:01.700 This is the general purpose registers as well, often used to hold additional arguments to functions 08:01.700 --> 08:08.330 and in the code it is used to store values such as the result of arithmetic operations before they are 08:08.330 --> 08:09.080 displayed. 08:09.080 --> 08:12.240 And we also have the r BP. 08:12.260 --> 08:17.060 We use that somewhere here r BP here. 08:18.220 --> 08:18.920 Let me find. 08:18.940 --> 08:19.390 Yeah. 08:19.960 --> 08:20.740 RVP. 08:22.100 --> 08:24.450 This is a stack pointer register. 08:24.470 --> 08:31.100 This is points to the top of the stack and it is adjusted to allocate and deallocate memory for local 08:31.100 --> 08:32.960 variables and function calls. 08:33.880 --> 08:43.450 And we have the rags, RTI, RSI, RDX, Rbx and RSP are part of the x86 64 calling convention and are 08:43.450 --> 08:48.910 used to pass arguments and manage function calls between the caller and Callie. 08:49.330 --> 08:59.020 And we also have in C and D, a C here, which we use the incrementing and decrementing operations. 09:01.890 --> 09:03.450 Uh, it should be somewhere here. 09:03.720 --> 09:04.240 I see. 09:04.280 --> 09:10.800 And I see here these instructions, uh, for incrementing and decrementing a register or memory location 09:10.800 --> 09:12.600 by one, respectively. 09:12.600 --> 09:16.680 So they are used to perform simple arithmetic operations quickly. 09:17.040 --> 09:22.380 We have the add and sub here. 09:23.440 --> 09:30.130 This instruction that adds a value to a register or memory location, and it is used for addition parents 09:30.130 --> 09:31.060 and for sub. 09:31.060 --> 09:37.270 Here is this instruction that subtracts a value from a register or memory location and it is used for 09:37.270 --> 09:49.180 subtraction operations and we also have s a L and s r a s a r here, which should be somewhere. 09:50.700 --> 09:54.360 Here's are s a are here and. 09:55.280 --> 09:55.850 Sal. 09:57.320 --> 10:03.350 So these are the shift arithmetic left and shift arithmetic right instructions are used for shifting 10:03.350 --> 10:08.720 the bits of registers or memory location to the left or right, and they can be used for multiplication 10:08.720 --> 10:12.050 and division by powers of two respectively. 10:12.050 --> 10:20.840 And we also have here I'm u l you should see somewhere here instruction use. 10:20.840 --> 10:24.440 This instruction is used for sine multiplication of two values. 10:24.440 --> 10:32.060 It is often used with two operands and the result is stored in the destination operand. 10:32.670 --> 10:34.190 And we have it here. 10:34.200 --> 10:39.660 This is this instruction used for sign division and it divides the contents of the accumulator by the 10:39.660 --> 10:46.980 specified operand and stores, the quotient in the accumulator and the remainder in the specified register. 10:46.980 --> 10:48.840 And we have the printf. 10:48.870 --> 10:52.710 This is a function from the C library used for formatted output. 10:52.710 --> 10:57.840 And in the code it's called with arguments stored in registers and displays the formatted message to 10:57.840 --> 10:58.680 the console.