Basics of Assembly (this helps me learn as well)

Assembly is something I am starting to learn more in depth. I will format this later

We start off with the smallest data piece availble this is called

a bit 0 it can only be a 1 or 0

you have 1 nibble which is 0000 its 4 bits, its also half of a byte.  the max value of a nibble is 15 which is 1111 in binary and F in hex which is a base 16 number system

———

nibble

———

1 nibble 0000

4 bits 0000

 

hex goes from 1 to 9 then a to F A being 10 and F being 15

1

2

3

4

5

6

7

8

9

10  A

11  B

12  C

13  D

14  E

15  F

——-

byte

——-

2 nibbles 0000 0000

8 bits 00000000

a byte has a maximum value of 255 in decimal or again FF

then you have a

——-

word

——- 

2 bytes 00000000 00000000

4 nibbles 0000 0000 0000 0000

16 bits 0000000000000000

word has a max value of FFFF which is also 65,336

for every nibble

Registers

There are areas on a computer where data can be stored and manipulated these are called registers.

There is 4 general purpose registers AX, BX, CX, and DX

These are split up into 8 bit registers AX is split into AH and AL

BX and DX, you add a letter E in front and you get EAX and EDX

You also have index registers such as SI DI and IP

On 32 bit this becomes EBX EDX ESI EIP and EDI

SI = Source Index

DI = destination Index

IP = instruction pointer

The Stack

BP and SP are the stack registers, The stack is like having a stack of plates, and anything most recent used is taken off the top of the pile.

 

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