x86 Assembly Crash Course

Prompts and answers

• What are the hex codes that denote the assembly operations called?
  Opcodes
• Which type of operand is denoted by square brackets?
  memory operand
• In mov eax, ebx, which register is the destination operand?
  eax
• What instruction performs no action?
  nop
• Which flag will be set if the result of the operation is zero? (Answer in abbreviation)
  ZF
• Which flag will be set if the result of the operation is negative? (Answer in abbreviation)
  SF
• In a subtraction operation, which flag is set if the destination is smaller than the subtracted value?
  Carry Flag
• Which instruction is used to increase the value of a register
  inc
• Do the following instructions have the same result? (yea/nay)
  yea
• Which flag is set as a result of the test instruction being zero?
  Zero flag
• Which of the below operations uses subtraction to test two values? 1 or 2?
  1
• Which flag is used to identify whether a jump will be taken or not after a jz or jnz instruction?
  Zero Flag
• Which instruction is used for performing a function call?
  call
• Which instruction is used to push all registers to the stack?
  pusha
• While running the MOV instructions, what is the value of [eax] after running the 4th instruction? (in hex)
  0x00000040
• What error is displayed after running the 6th instruction from the MOV instruction section?
  Memory to memory data movement is not allowed.
• Run the instructions from the stack section. What is the value of eax after the 9th instruction? (in hex)
  0x00000025
• Run the instructions from the stack section. What is the value of edx after the 12th instruction? (in hex)
  0x00000010
• Run the instructions from the stack section. After POP ecx, what is the value left at the top of the stack? (in hex)
  0x00000010
• Run the cmp and test instructions. Which flags are triggered after the 3rd instruction?
  PF,ZF
• Run the test and the cmp instructions. Which flags are triggered after the 11th instruction?
  CF,SF
• Run the instructions from the lea section. What is the value of eax after running the 9th instruction? (in hex)
  0x0000004B
• Run the instructions from the lea section. What is the final value found in the ECX register? (in hex)
  0x00000045