The contents of register BL and register AL of 8085 microprocessor are 49H and 3AH, respectively. The contents of AL, the status of carry flag (CF), and sign flag (SF) after executing the instruction SUB AL, BL are:

Question

In case of DMA, after the completion of the transfer, the processor is required to be notified of the completion. This is done through.

Answer 1

The SUB AL, BL instruction executes AL = AL − BL. With AL = 3AH and BL = 49H, the subtraction 3AH − 49H results in −0F H, which is F1H in two’s complement hexadecimal. Due to the negative result, a borrow occurs, setting the Carry Flag (CF) to 1. The Sign Flag (SF) is also set to 1, as the most significant bit of the result indicates a negative number.

List I	List II
A. Supervisor mode	I. Entered when the processor encounters a software interrupt instruction
B. Abort Mode	II. Entered in response to memory fault
C. Fast Interrupt Mode	III. Entered whenever the processor receives an interrupt signal from a designated fast interrupt source
D. Interrupt Mode	IV. Entered whenever the processor receives an interrupt signal from any other source

Firm 2	Cooperate	Compete
Firm 1	5, 5	0, 10
Compete	10,0	2, 2

The contents of register BL and register AL of 8085 microprocessor are 49H and 3AH, respectively. The contents of AL, the status of carry flag (CF), and sign flag (SF) after executing the instruction SUB AL, BL are:

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The Correct Option is A

Solution and Explanation

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