Microprocessor Concepts Quiz

Moves the hexadecimal value 123AH into the AX register.

MOV AX, DS copies the contents of the Data Segment register (DS) into the AX register.

LIFO (Last-In, First-Out) memory organization where items are added and removed from the top.

Pushes the contents of the AX register onto the stack.

Removes and stores at the particular register from the stack.

When BP addresses data, it refers to the Stack Segment (SS).

When BX addresses data, it most often refers to the Data Segment (DS).

When IP addresses memory, it refers to the Code Segment (CS) which contains the instructions.

Subtracts the value in the AX register from the word-sized memory location addressed by DI (within the data segment).

Subtracts the value in the BX register from the value in the AX register, storing the result in AX.

Performs signed multiplication.

Results in a 16-bit product.

Results in a 32-bit product.

Multiplies the value in the AL register by the value in the CL register, storing the unsigned product in the AX register.

Multiplies the value in the AX register by the value in the CX register, storing the signed product in the DX:AX registers.

The IDIV instruction performs signed integer division, dividing the 32-bit dividend (DX:AX) by a byte or word operand. The quotient is stored in AX (or AL for byte division) and the remainder in DX (or AH for byte division).

The DIV instruction performs unsigned integer division, dividing the 32-bit dividend (DX:AX) by a byte or word operand. The quotient is stored in AX (or AL for byte division) and the remainder in DX (or AH for byte division).

When dividing with DIV or IDIV, you can access the operand from the stack segment memory using [BP]. This allows you to operate on data stored on the stack.

Arithmetic and logic instructions, such as addition, subtraction, AND, OR, etc., affect the flags in the flag register. The flags indicate the result of the operation (carry, parity, zero, sign etc.).

The TEST instruction performs a bitwise AND operation between the destination operand and the source operand. It sets the flags based on the result, but doesn't modify the destination operand.

Both NOT and NEG are arithmetic instructions: NOT performs a bitwise complement (inverting all bits), while NEG computes the two's complement of the operand, meaning its arithmetic negation.

Instructions like AND, OR, and XOR are used to manipulate individual bits within registers or memory. This enables you to selectively modify specific bits based on their logical combination.

The OR instruction performs a bitwise OR operation between the destination and source operands. Sets bits in the destination operand if either corresponding bits in the destination or source are set.

The mode field value of '11' indicates the use of register-addressing mode.

A mode field value of '00' implies no displacement is used, meaning the address is directly accessed.

A mode field value of '10' signifies an 8-bit signed extended displacement, which is added to the base address.

A mode field value of '01' denotes a 16-bit signed displacement, which is added to the base address.

The machine language instruction '8A15H' translates to the assembly language instruction MOV [DI], DL.

The machine language instruction '8BECH' translates to the assembly language instruction MOV BP, SP.

The assembly instruction 'MOV SI, [BX+2]' moves the value stored at the memory location addressed by BX+2 into the SI register.

The assembly instruction 'MOV [BX+4], DI' copies the value from the DI register into the memory location addressed by BX+4.

The Zero Flag (ZF) is a status flag in a CPU that is set to 1 if the result of an arithmetic or logical operation is zero, otherwise it is reset to 0.

The Sign Flag (SF) is a status flag that reflects the sign bit of the result of an arithmetic or logical operation. If the most significant (leftmost) bit of the result is 1, indicating a negative number, SF is set to 1. Otherwise, SF is 0.

In real mode, memory is addressed using a segment and offset. The physical address is calculated by multiplying the segment value by 16 and adding the offset value.

Segment registers (CS, DS, SS, ES) hold the starting address of a memory segment, which is then used to calculate the actual physical address of data within the segment.

A descriptor is a data structure that holds information about a memory segment, including its location, length, and access rights.

Protected mode is an operational mode of a CPU that provides more sophisticated memory management and security features, giving the operating system greater control over memory access.

A Local Descriptor Table (LDT) is a table that contains descriptors specific to a particular process or task, providing access to the memory space dedicated to that process.

The Global Descriptor Table (GDT) is a system-wide table that contains descriptors for memory segments that are shared across different tasks or processes.

Performs a bitwise exclusive OR operation between the value in the AX register and the value at the memory location calculated by adding the contents of the SI and BX registers. The result is stored in the AX register.

Performs a bitwise NOT operation on the byte stored at the memory location 0300H. This effectively inverts all the bits of the byte.

This instruction performs a logical right shift on the ECX register by 10 bits. In a logical right shift, zeros are shifted in from the left side, potentially losing data on the right side.

This instruction performs an arithmetic left shift on the BX register by 5 bits. In an arithmetic left shift, the most significant bit (MSB) is copied to the leftmost position. The least significant bit (LSB) is filled with a 0.

This instruction performs a rotate left through carry operation on the BL register by 6 bits. In a rotate operation, the bits are shifted circularly (shifted bits re-enter the register from the other side). The carry flag is involved as the MSB goes to the carry flag and the carry flag goes to the LSB.

This instruction performs a rotate right through carry operation on the AH register by the number of bits specified in the CL register.

This instruction performs a rotate right on the EDX register by 18 bits. Bits shifted out of the register are re-inserted from the other side.

The opcode field of a machine language instruction determines the operation to be performed. In many architectures, it consists of one or two bytes encoding the specific action the processor will take.