In an 8086, AL = 19 BCD & BL = 36 BCD prior to execution of following example ADD AL, BL DAA What will be content of AL after execution of the example ?
5 5
To solve this problem of adding two BCD numbers using the 8086 microprocessor, we first need to understand what happens during each of the given assembly instructions: ADD AL, BL and DAA.
- Initial Conditions:
- \(AL = 19_{BCD}\)
- \(BL = 36_{BCD}\)
- Performing ADD AL, BL:
- This operation will add the contents of \(BL\) to \(AL\).
- Adding \(19_{BCD} + 36_{BCD}\) as simple binary without considering BCD:
- \(19_{BCD} = 25_{base\ 10}\\)
- \(36_{BCD} = 54_{base\ 10}\\)
- Binary sum:
- \(11001_{binary} (25)\)
- +
- \(110010_{binary} (54)\)
- =
- \(101111_{binary} (79)\)
- The result is stored in \(AL\).
- Applying DAA (Decimal Adjust for Addition):
- The
DAAinstruction adjusts the result in \(AL\) to form a valid BCD. - Because the binary result \(79\) exceeds the maximum of \(9\) in lower 4 bits:
- \(79_{binary} = 7D_{BCDfe}\)
- The DAA will adjust it by:
- Add 6 to lower four bits: \(D\)
- So, \(85_{base\ 10} = 50_{BCD}\\)
- Add 6 to lower four bits: \(D\)
- The
- This adjustment gives the final correct BCD result in \(AL\) as 55.
Conclusion:
After executing these instructions, the content of AL becomes 55, which corresponds to option 2. Thus, the correct answer is 5 5.
Similar Questions
If SS = 3000 H and SP = 2000 H in 8086 microprocessor, in which memory addresses the contents of BL and BH are stored respectively, when PUSH BX instruction is executed.
The BIU of 8086 contains 16 bit segment registers. What is the width of address sent out by BIU of 8086 miocroprocessor?
Loop 1 : MOV A, P1
MOV P2, A
JNB P3.3, Loop1
The program does the following
In 8051 micro controller
A. INT0 and INT1 pins are normally low
B. Timer1 Interrupt Flag is auto cleared after occurrence
C. Serial interrupt is auto cleared after occurrence
D. Timer 0 Vector location is 000B H
Choose the correct answer from the options given below:
In 8086
A. The stack memory is a FIFO (First In First Out)
B. The JMP instruction cannot be prefixed with segment override prefix
C. SAHF and POPF instructions affect the flag register
D. DAS instruction cannot be used for 8 bit operations.
Choose the correct answer from the options given below :
In 8051
A. INT0 and INT1 can be made edge triggered by programming TCON
B. On reset serial communication interrupts has highest priority
C. Upon reset all interrupts are enabled
D. Only one interrupt is set aside for serial communication.
Choose the correct answer from the options given below:
Match List I with List II in 8086 Micro processor
LIST I LIST II A. Direct memory addressing data memory I. MOV [SI], 2500 H B. Immediate Addressing II. PUSHF C. Flag Manipulation III. RET D. Control transfer IV. MOV BX, [2000 H] Choose the correct answer from the options given below:
Arrange following interrupts in order of polling (checking interrupt conditions) after every instructions.
A. Serial Interrupt
B. External 1 Interrupt
C. Timer 1 Interrupt
D. External 0 Interrupt
Choose the correct answer from the options given below :
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : Some instruction read the contents of an internal port latch instead of reading the status of an external pin.
Reason R : We must not make a distinction between reading the status of the input pin and internal latch of the output port.
In the light of the above statements, choose the most appropriate answer from the options given below :
The ALE line of an 8085 microprocessor is used to
Important Questions from Microprocessors
An 8086 address bus is a/an _____ -bit bus
Program counter for any counter:
In the pin out configuration of the 8085 microprocessor, the sequential input data is represented by
Which of the following functions is not performed by a microprocessor?
Match the columns.
Pin
Description
a. D 0-D 7
1. Reset Input
b. RESET
2. Data Lines
c. A 0,A 1
3. Internal Address
