1What does the JMP instruction do?
Transfers program control unconditionally to another part of the program.
2What does “unconditional” mean in JMP instruction?
It always jumps regardless of any condition.
3What determines conditional jumps?
Status flags such as Zero, Carry, Sign, Overflow, and Parity.
4What do JE and JZ mean?
Jump if Equal or Jump if Zero.
5What do JNE and JNZ mean?
Jump if Not Equal or Jump if Not Zero.
6What does JA or JNBE mean?
Jump if Above or Jump if Not Below or Equal (for unsigned data).
7What does JAE or JNB mean?
Jump if Above or Equal or Jump if Not Below.
8What does JB or JNAE mean?
Jump if Below or Jump if Not Above or Equal.
9What does JBE or JNA mean?
Jump if Below or Equal or Jump if Not Above.
10What does JG or JNLE mean?
Jump if Greater or Jump if Not Less or Equal (for signed data).
11What does JGE or JNL mean?
Jump if Greater or Equal or Jump if Not Less.
12What does JL or JNGE mean?
Jump if Less or Jump if Not Greater or Equal.
13What does JLE or JNG mean?
Jump if Less or Equal or Jump if Not Greater.
14What does JS mean?
Jump if Sign (Negative).
15What does JNS mean?
Jump if No Sign (Positive).
16What does JC mean?
Jump if Carry.
17What does JNC mean?
Jump if No Carry.
18What does JO mean?
Jump if Overflow.
19What does JNO mean?
Jump if No Overflow.
20What does JP or JPE mean?
Jump if Parity Even.
21What does JNP or JPO mean?
Jump if Parity Odd.
22What does the LOOP instruction do?
Repeats a block of instructions a specific number of times.
23Which register determines the number of LOOP repetitions?
The CX register.
24What happens to CX after each LOOP execution?
CX decreases by 1.
25When does the LOOP end?
When CX becomes zero.
26What is a macro in assembly language?
A name that defines a set of instructions substituted wherever it appears.
27Where must a macro be declared?
Before a segment.
28What is the syntax for defining a macro?
macro_name macro(dummy_argument) … endm.
29What is the purpose of the dummy_argument in a macro?
It acts as a placeholder for additional data or values.
30What are the benefits of using macros?
They make programs shorter, easier to read, and reusable.
31What does the ADD instruction do?
Performs binary addition.
32What does the SUB instruction do?
Performs binary subtraction.
33In ADD or SUB, what can operand1 be?
A register or a memory location.
34In ADD or SUB, what can operand2 be?
A register, memory location, or immediate value.
35Why is AAA used?
To adjust ASCII addition results in the AX register to correct decimal form.
36What does AAA stand for?
ASCII Adjust after Addition.
37What does the AAM instruction do?
Adjusts ASCII result after multiplication.
38Why do operands need to be ANDed with 0Fh before AAM or AAD?
To clear the leftmost hex digit of 3s.
39What is the function of MUL?
Multiplies unsigned data.
40What is the function of IMUL?
Multiplies signed data.
41Where is the multiplicand stored for byte multiplication?
In the AL register.
42What is the purpose of the OR ax,3030h instruction?
To convert the result to ASCII format.
43What does the DIV instruction do?
Divides unsigned data.
44What does the IDIV instruction do?
Divides signed data.
45Where is the quotient stored after division?
In the AL register.
46Where is the remainder stored after division?
In the AH register.
47What is the purpose of AAD?
Adjusts ASCII values before division.
48What is a procedure in assembly language?
A sequence of instructions that performs a specific task.
49How does a procedure start and end?
With PROC and ENDP directives.
50Which instruction calls a procedure?
CALL.
51Which instruction returns control from a procedure?
RET.
52What instruction can also transfer control to a procedure but is less structured?
JMP.
53What is the benefit of using procedures?
They make programs modular, reusable, and easier to maintain.
54Which interrupt handles DOS disk services?
INT 21H.
55What does INT 21H Service 3CH do?
Creates a new file.
56What does AH = 3CH represent?
Service number for file creation.
57What is stored in DX for INT 21H 3CH?
Address of the ASCIIZ string containing the file path and name.
58What does CX represent in INT 21H 3CH?
File attribute or type.
59What happens if file creation is successful?
File is created and carry flag is cleared.
60What happens if file creation fails?
Carry flag is set, and error code is returned in AX.
61What does error code 03 mean?
File not found.
62What does error code 04 mean?
Path not found.
63What does error code 05 mean?
Access denied.
64What does error code 11 mean?
Invalid format.
65What does error code 21 mean?
Drive not ready.
66What does INT 21H Service 41H do?
Deletes a file.
67What files cannot be deleted using INT 21H 41H?
Read-only files.
68What does INT 21H Service 56H do?
Renames a file.
69What happens if INT 21H 56H fails?
File not found or protected.
70What does INT 21H Service 39H do?
Creates a directory.
71What does AH = 39H represent?
Function number for creating a directory.
72What does INT 21H Service 3AH do?
Removes a directory.
73When can you not delete a directory?
When it is the current directory or contains files.
74What does INT 21H Service 3BH do?
Changes the current working directory.
75What does INT 21H Service 47H do?
Retrieves the current directory.
76What does DL represent in INT 21H 47H?
Drive number (0 = default, 1 = A:, etc.).
77What does SI represent in INT 21H 47H?
Address of the buffer to store the directory path.
78What are operands?
The data or values that an instruction works on.
79Give an example of operands.
In MOV AX, BX — AX and BX are operands.
80What are directives?
Commands for the assembler, not the CPU.
81What do directives do?
Define data, reserve memory, or control program structure.
82Give examples of directives.
DB, DW, SEGMENT, ENDS, ORG, END.
83What are labels?
Names given to memory addresses or code locations.
84What is the purpose of labels?
Used for branching, loops, or procedures.
85What are instructions?
Commands executed by the CPU to perform operations.
86Give examples of instructions.
MOV, ADD, SUB, JMP, INT.