Assembler

Registers

• Working memory
• Different purposed
• Fixed width

The stack

• LIFO data structure
• Is an array
• Stack pointer (register)
• Random access

The program for compiling assembler code

sudo apt install nasm

Comtiling binary file

nasm -f elf32 ex1.asm -o ex1.o

elf32 = executable and linking format

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This is a command used in the process of compiling and linking assembly code. It invokes the linker (ld) to create an executable file (ex1) from an object file (ex1.o) for a 32-bit x86 system (elf_i386).

ld -m elf_i386 ex1.o -o ex1

For executing we use commands

./ex1
echo $?

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mov ebx, 123 // ebx = 123 mov eax, ebx // eax = ebx add ebx, ecx // ebx += ecx sub ebx, edx // ebx -= edx mul ebx // eax *= ebx div edx // eax /= edx

je A, B // Jump if Equal jne A, B // Jump if NOT Equal jg A, B // Jump if Greater jge A, B // Jump if Great or Equal jl A, B // Jump if Less jle A, B // Jump if Less or Equal

Command 'call'

• Pushes EIP to stack
• Performs jump

debugging assembly code with c++ https://godbolt.org

cours https://www.udemy.com/course/assembly-language-programming/?utm_source=adwords&utm_medium=udemyads&utm_campaign=Search_DSA_Beta_Prof_la.EN_cc.ROW-English&campaigntype=Search&portfolio=ROW-English&language=EN&product=Course&test=&audience=DSA&topic=&priority=Beta&utm_content=deal4584&utm_term=_._ag_162511579564_._ad_696197165424_._kw__._de_c_._dm__._pl__._ti_dsa-1677053911888_._li_9198704_._pd__._&matchtype=&gad_source=2&gclid=EAIaIQobChMIxe`i7m6XSiQMVEplQBh0jWB1vEAAYASAAEgIoEPD_BwE&couponCode=2021PM20

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