Very clearly explained. Thank you.

winslows :’v

Visual Studio zoom in = Alt+ mouse scrolling, very informative video thank you.

It would be interesting to see how an FPGA is programmed.

Great video!

Intel 80386 (32 bit):
A closer look to the possible sorts of bytes of one instruction:
Instruction Prefix 0 or 1 Byte
Address-Size Prefix 0 or 1 Byte
Operand-Size Prefix 0 or 1 Byte
Segment Prefix 0 or 1 Byte
Opcode 1 or 2 Byte
Mod R/M 0 or 1 Byte
SIB, Scale Index Base (386+) 0 or 1 Byte
Displacement 0, 1, 2 or 4 Byte (4 only 386+)
Immediate 0, 1, 2 or 4 Byte (4 only 386+)

Format of Postbyte(Mod R/M from Intel-manual)
——————————————
MM RRR MMM

MM – Memory addressing mode
RRR – Register operand address
MMM – Memory operand address

RRR Register Names
Filds 8bit 16bit 32bit
000 AL AX EAX
001 CL CX ECX
010 DL DX EDX
011 Bl BX EBX
100 AH SP ESP
101 CH BP EBP
110 DH SI ESI
111 BH DI EDI

—

(Note: We observe the next two tables from the 16 bit address mode. The D flag in the code-segment descriptor is not set. The default size of memory access and the operand size (without size prefixes) is 16 bit.) The first table below shows which of the 16 bit register can be used as an address register and the default segment register(Sreg) of them, if no segment override prefix is used.

16bit memory (No 32 bit memory address prefix)
MMM Default MM Field
Field Sreg 00 01 10 11=MMM is reg
000 DS [BX+SI] [BX+SI+o8] [BX+SI+o16]
001 DS [BX+DI] [BX+DI+o8] [BX+DI+o16]
010 SS [BP+SI] [BP+SI+o8] [BP+SI+o16]
011 SS [BP+DI] [BP+DI+o8] [BP+DI+o16]
100 DS [SI] [SI+o8] [SI+o16]
101 DS [DI] [DI+o8] [SI+o16]
110 SS [o16] [BP+o8] [BP+o16]
111 DS [BX] [BX+o8] [BX+o16]
Note: MMM=110,MM=0 Default Sreg is DS !!!!

32bit memory (Has 67h 32 bit memory address prefix)
MMM Default MM Field
Field Sreg 00 01 10 11=MMM is reg
000 DS [EAX] [EAX+o8] [EAX+o32]
001 DS [ECX] [ECX+o8] [ECX+o32]
010 DS [EDX] [EDX+o8] [EDX+o32]
011 DS [EBX] [EBX+o8] [EBX+o32]
100 SIB [SIB] [SIB+o8] [SIB+o32]
101 SS [o32] [EBP+o8] [EBP+o32]
110 DS [ESI] [ESI+o8] [ESI+o32]
111 DS [EDI] [EDI+o8] [EDI+o32]
Note: MMM=110,MM=0 Default Sreg is DS !!!!

—

SIB is (Scale/Base/Index)
SS BBB III
Note: SIB address calculated as:
=+*(2^(Scale))

Fild Default Base
BBB Sreg Register Note
000 DS EAX
001 DS ECX
010 DS EDX
011 DS EBX
100 SS ESP
101 DS o32 if MM=00 (Postbyte)
SS EBP if MM<>00 (Postbyte)
110 SS ESI
111 DS EDI

Fild Index
III register Note
000 EAX
001 ECX
010 EDX
011 EBX
100 never Index SS can be 00
101 EBP
110 ESI
111 EDI

Fild Scale coefficient
SS =2^(SS)
00 1
01 2
10 4
11 8

I use fasm (flatassembler by Tomasz Grysztar) for years and now the processors became so complicated so decided to program C and C++ instead of ASM, and only for critical parts of code I use Assembly language if translation of C code doesn’t met my expectations. Most of daily job I do in scripting languages as a prototype but if something must be truly fast then the language should be compiled and as a result to become a machine code. The very equal effect you may achieve using C, which is more human readable than different mnemonics for different processor types: ARM, x86, Sparc, etc…sorry for my English, I’m not talented in writing something what isn’t a code. I hope you understand my point because I barely understand myself 😉

23:36 lmao spitting bars, I have no idea what any of that stuff means but good on ya 😀

This is great; very informative. Many thanks.

Earned yourself a like and a subscribe. Fantastic video.

I vote for more Assembly videos and tutorials! if you would please 🙂

Aw man, I got lost, you have a good video presence and it-s well paced though. I-ll take a second look later.

Thank you so much for this!

As a almost new to this coding world…I didn’t understand 95% of what u said…how can i start to understand….???

Thanks for this video. We’re covering assembly in one of my university courses this semester, and it’s been a pain. This helped clarify a lot!

Thank you for this awesome explanation. I program in much higher-level programming languages but I thought it could be helpful to know what’s going on under the hood. Your video was very helpful.
P.S. it’s quite refreshing to hear a British accent every once in a while, Computer Science is full of american people 😀

Hey javidx9. I recently wanted to learn Assembly but there are tons of assemblers. Which one do you suggest me to use? And what things should I know before learning it.

what the problem
#include

using namespace std;

class fact{
int* number;
int *sum;
public:
fact(){number=new int; //constructor
*sum=1;
number=new int ;

}
~fact(){
delete sum;

delete number;
}
void print(){

cout< <"ENTER NUMBER: "; cin>>*number;

}
void print2(){
if(*number==1||*number==0)
cout< <"!"<<*number<<"= "<<1; else{ cout<<"!"<<*number<<"= "; for(;*number>0;*number-=1){
*sum=(*sum)*(*number);
cout<<*number; if(*number==1) cout<<"="<<*sum; else cout<<"*"; }}} }; int main() { fact a; a.print(); a.print2(); return 0; }

Thank you for your great video! Your English is perfect. I’m russian and my English level is intermediate, but I understood almost everything… about 80% My like and subscription are yours =)

This introduction to assembly was very enlightening and reasonably simplified. Thank you very much!

If you want to get your head dissembled , this is the language to learn.

no words can describe my admiration for ASM and the people who are fluent in it, but for me it’s still a dark magic