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Assembly Language

  • Assembly is a low-level programming language used to directly translate instructions into the computer’s machine code in a more human-readable way.

Spesific Use Case

  • Embedded systems that have limited memory and hardware capacity

  • Direct hardware testing

  • Software optimization

Compilation Process

  1. Preprocessing - prepare the user’s code for machine code by removing comments, expanding included macros, and performing any code maintenance prior to handing the file to the compiler.

  2. Compiling - the process of taking the expanded file from the preprocessor and translating the program into an optimized Assembly language.

  3. Assembling - process of taking an assembly language program and using an assembler to generate machine code.

  4. Linking - process of filling in function calls, including additional objects, libraries, and source code from other locations into the main source code.

ARM Arithmethic Operations Opcode

Instruction
Function
Example
Explaination

ADD

adding numbers

ADD a, b, c

  • adding value b and c, stored in a

ADDI

adding immidiate number (constant value) rather than being fetched from registers or memory location

ADDI a, c, 10

  • adding 10 to a, and stored in c

SUB

substracting number

SUB a, b, c

  • substract value and c, stored in a

MUL

multiply number

MUL a, b, c

  • multiply value b and c, stored in a

Bitwise Logic Operations

Syntax

{instruction} {destination}, {source1}, {source2}

Instruction
Example
Comparison in C
Explaination

AND

AND a, b, c

a = b && c

  • result of b AND c, stored in a

ORR

ORR a, b, c

a = b || c

  • result of b OR c, stored in a

EOR

EOR a, b, c

a = b ^ c

  • result of b XOR c, stored in c

BIC

BIC a, b, c

a = b & (!c)

  • the result of b AND negation of c, stored in a

Others

Instruction
Example
Comparison in C
Explaination

CMP

CMP a, b

a == b

  • compares value at a and b

MOV

MOV a, 1

a = 1

  • assign value 1 to a

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