Podcast
Questions and Answers
What is the value of AL after executing 'mov al,[arrayB+1]'?
What is the value of AL after executing 'mov al,[arrayB+1]'?
What happens if you execute 'mov ax,[arrayW-2]'?
What happens if you execute 'mov ax,[arrayW-2]'?
What value is stored in EAX after executing 'mov eax,[arrayD+4]'?
What value is stored in EAX after executing 'mov eax,[arrayD+4]'?
How will the values in arrayD change after executing the rearrangement program provided?
How will the values in arrayD change after executing the rearrangement program provided?
Signup and view all the answers
What is the result of executing 'add ax,[myBytes+1]' if 'myBytes' contains BYTE values 80h, 66h, 0A5h?
What is the result of executing 'add ax,[myBytes+1]' if 'myBytes' contains BYTE values 80h, 66h, 0A5h?
Signup and view all the answers
Why doesn't 'arrayB+1' produce the value 11h?
Why doesn't 'arrayB+1' produce the value 11h?
Signup and view all the answers
What will be the final value of 'arrayD' after executing the given rearrangement program?
What will be the final value of 'arrayD' after executing the given rearrangement program?
Signup and view all the answers
What is the value of AX after the operation 'add ax,1'?
What is the value of AX after the operation 'add ax,1'?
Signup and view all the answers
What is the value of the Zero Flag (ZF) after 'add al,1' if AL is initially 00h?
What is the value of the Zero Flag (ZF) after 'add al,1' if AL is initially 00h?
Signup and view all the answers
Which condition triggers the Overflow Flag (OF) to be set during addition?
Which condition triggers the Overflow Flag (OF) to be set during addition?
Signup and view all the answers
What operation does the NEG instruction perform on its operand?
What operation does the NEG instruction perform on its operand?
Signup and view all the answers
What is the Carry Flag (CF) value after 'add bh,95h' if BH is initially 6Ch?
What is the Carry Flag (CF) value after 'add bh,95h' if BH is initially 6Ch?
Signup and view all the answers
When the processor executes "neg valB", what is the resulting state of the Carry Flag?
When the processor executes "neg valB", what is the resulting state of the Carry Flag?
Signup and view all the answers
What is the value of AL after 'mov al,-2'?
What is the value of AL after 'mov al,-2'?
Signup and view all the answers
Which flag is set when the result of an arithmetic operation equals zero?
Which flag is set when the result of an arithmetic operation equals zero?
Signup and view all the answers
What happens to the Overflow Flag when performing 'add al,1' with AL set to 7Fh?
What happens to the Overflow Flag when performing 'add al,1' with AL set to 7Fh?
Signup and view all the answers
What happens to the Overflow flag after executing "neg valC" where valC is set to -128?
What happens to the Overflow flag after executing "neg valC" where valC is set to -128?
Signup and view all the answers
What is the value of the Sign Flag (SF) after the operation 'sub al,3' if AL starts with 02h?
What is the value of the Sign Flag (SF) after the operation 'sub al,3' if AL starts with 02h?
Signup and view all the answers
What is the outcome of 'add al,92h' if AL is initially set to 80h?
What is the outcome of 'add al,92h' if AL is initially set to 80h?
Signup and view all the answers
In the expression Rval = -Xval + (Yval – Zval), what is the value of Rval after the assembly instructions are executed?
In the expression Rval = -Xval + (Yval – Zval), what is the value of Rval after the assembly instructions are executed?
Signup and view all the answers
Which of the following flags is NOT affected by the MOV instruction?
Which of the following flags is NOT affected by the MOV instruction?
Signup and view all the answers
What will be the result in the ALU's status flags after the operation "neg [valB + 1]"?
What will be the result in the ALU's status flags after the operation "neg [valB + 1]"?
Signup and view all the answers
When compiling Rval = Xval - (-Yval + Zval), which statement reflects the assembly language translation correctly?
When compiling Rval = Xval - (-Yval + Zval), which statement reflects the assembly language translation correctly?
Signup and view all the answers
What is the value of AX after the loop terminates if the initial value was set to 6 and ECX was set to 4 with the LOOP instruction?
What is the value of AX after the loop terminates if the initial value was set to 6 and ECX was set to 4 with the LOOP instruction?
Signup and view all the answers
How many times will the second loop labeled as X2 execute if ECX is initialized to 0?
How many times will the second loop labeled as X2 execute if ECX is initialized to 0?
Signup and view all the answers
What happens to the ECX register in a nested loop structure?
What happens to the ECX register in a nested loop structure?
Signup and view all the answers
What is the largest possible forward jump when using a single signed byte for the relative offset?
What is the largest possible forward jump when using a single signed byte for the relative offset?
Signup and view all the answers
In the LOOP instruction example provided, what machine code corresponds to the instruction 'mov ecx,5'?
In the LOOP instruction example provided, what machine code corresponds to the instruction 'mov ecx,5'?
Signup and view all the answers
What is the hexadecimal representation of the negative offset used for the backward jump in the LOOP instruction?
What is the hexadecimal representation of the negative offset used for the backward jump in the LOOP instruction?
Signup and view all the answers
What is the initial action of the loop at location 00000009?
What is the initial action of the loop at location 00000009?
Signup and view all the answers
If a signed byte is used for a relative offset, which of the following values can be achieved by a backward jump?
If a signed byte is used for a relative offset, which of the following values can be achieved by a backward jump?
Signup and view all the answers
What operation is performed to scale an indexed operand in the provided example?
What operation is performed to scale an indexed operand in the provided example?
Signup and view all the answers
In the context of pointers, what does the variable 'ptrW' represent?
In the context of pointers, what does the variable 'ptrW' represent?
Signup and view all the answers
What would be the result of the instruction 'mov al, arrayB[esi*TYPE arrayB]' if 'esi' is 4?
What would be the result of the instruction 'mov al, arrayB[esi*TYPE arrayB]' if 'esi' is 4?
Signup and view all the answers
What does the instruction 'mov ax, [esi]' do in the context of pointers?
What does the instruction 'mov ax, [esi]' do in the context of pointers?
Signup and view all the answers
Which of the following statements is true regarding general-purpose registers?
Which of the following statements is true regarding general-purpose registers?
Signup and view all the answers
What does the LENGTHOF operator measure in data declarations?
What does the LENGTHOF operator measure in data declarations?
Signup and view all the answers
If an array is declared as 'array WORD 30 DUP(?),0,0', what is the result of LENGTHOF(array)?
If an array is declared as 'array WORD 30 DUP(?),0,0', what is the result of LENGTHOF(array)?
Signup and view all the answers
What does the SIZEOF operator return?
What does the SIZEOF operator return?
Signup and view all the answers
In a data declaration, which statement is true regarding spanning multiple lines?
In a data declaration, which statement is true regarding spanning multiple lines?
Signup and view all the answers
What is the LENGTHOF value for the digitStr BYTE '12345678',0 declaration?
What is the LENGTHOF value for the digitStr BYTE '12345678',0 declaration?
Signup and view all the answers
What is SIZEOF(array) if array is declared as 'array WORD 10,20,30,40,50,60'?
What is SIZEOF(array) if array is declared as 'array WORD 10,20,30,40,50,60'?
Signup and view all the answers
For an array initialized as 'array1 WORD 30 DUP(?),0,0', how many total WORDs are declared?
For an array initialized as 'array1 WORD 30 DUP(?),0,0', how many total WORDs are declared?
Signup and view all the answers
What is the effect of the SIZEOF operator on a declaration made across multiple lines?
What is the effect of the SIZEOF operator on a declaration made across multiple lines?
Signup and view all the answers
Study Notes
Assembly Language Programming - Chapter 4
- This chapter covers data transfers, addressing, and arithmetic operations in assembly language.
- Data transfer instructions include MOV, MOVSX, MOVZX, and XCHG. These instructions move data from one location to another. MOVSX and MOVZX are used with sign and zero extension, respectively. XCHG swaps the contents of two operands.
- Operand types include direct, direct-offset, indirect, and indexed.
- Arithmetic instructions: INC, DEC, ADD, SUB, and NEG impact registers and memory locations.
- Flags (Sign, Carry, Zero, Overflow) provide status information after arithmetic operations.
- Operators (OFFSET, PTR, TYPE, LENGTHOF, SIZEOF, TYPEDEF) are used for addressing and manipulating data.
- Branching instructions (JMP and LOOP) control the flow of execution.
- 64-bit programming is also discussed. This involves different register usage and operand size considerations.
Data Transfer Instructions
- MOV: Copies data from source to destination. Both operands need to be the same size.
- MOV reg, reg: Moves data between registers (e.g., MOV AX, BX).
- MOV reg, mem: Moves data from memory to a register (e.g., MOV AX, [variable]).
- MOV mem, reg: Moves data from a register to memory (e.g., MOV [variable], BX).
- MOV mem, imm: Moves immediate data to memory (e.g., MOV [variable], 100h).
- MOVSX: Moves and sign extends. Used for moving data between different size registers when using sign-based integer data types.
- MOVZX: Moves and zero extends. Used for moving data between different size registers when using unsigned integer data types.
- XCHG: Exchanges the contents of two operands.
Operand Types
- Immediate: A constant value.
- Register: A named CPU register.
- Memory: Location in memory addressed.
Arithmetic Instructions
- INC: Increments a value by 1.
- DEC: Decrements a value by 1.
- ADD: Adds two operands.
- SUB: Subtracts two operands.
- NEG: Reverses the sign of an operand.
Operators
- OFFSET: Returns the offset of a label.
- PTR: Specifies the data type of an operand.
- TYPE: Returns the size in bytes of a variable.
- LENGTHOF: Returns the number of elements in an array.
- SIZEOF: Returns the size in bytes of an array or variable.
- TYPEDEF: Defines a new data type.
JMP and LOOP Instructions
- JMP: Unconditional jump.
- LOOP: Conditional jump based on ECX value.
64-Bit Programming
- Different register usage compared to 32-bit assembly.
- Operands in 64-bit mode are 8, 16, 32 or 64 bits.
Overlapping Values
- Modifying a 32-bit register using values of different sizes will overwrite the bits in the register depending on the data sizes.
Invalid MOV Instructions
- Attempting to move data to or from a protected register.
- Moving values of different sizes (eg. moving a byte to a word).
- Memory to memory moves.
Arithmetic Flags
- Zero Flag (ZF): Set to 1 if the result of an operation is zero.
- Sign Flag (SF): Set to 1 if the result of an operation is negative.
- Carry Flag (CF): Set to 1 if result is unsigned out of range
- Overflow Flag (OF): Set to one if signed result is out of range.
Other
- Data transfer instructions, addition and subtraction, data-related operators, indirect addressing, JMP and LOOP instructions are covered.
- 64-bit programming concepts are introduced.
- Conventions to handle 64-bit data and operations are included.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz tests your knowledge of x86 assembly language instructions and their effects on registers and flags. You'll explore operations involving 'AL', 'AX', 'EAX', and various flags like CF, ZF, and OF. Challenge your understanding of memory operations and the behavior of data manipulations in assembly.
