Question

Discuss the internal structure of a digital computer with the importance of each
block. Also Show the purpose of each field in flag register

Answer 1

Answer:

Answer. The Flag register is a Special Purpose Register. ... There are total 9 flags in 8086 and the flag register is divided into two types: (a) Status Flags – There are 6 flag registers in 8086 microprocessor which become set(1) or reset(0) depending upon condition after either 8-bit or 16-bit operation.

Answer 2

In this question, we are asked to discuss the internal structure of a digital computer.

• Microprocessor 8086's flag register
• Flag register in the 8085 microprocessor is a requirement.
• A Special Purpose Register is the Flag Register. After any arithmetic and logical operation, the flag bits either get set to (1) or reset depending on the value of the result (0).
• Figure: Flag register format
• There are nine flags in all in 8086, and there are two different flag register types:
• (a) Status Flags - The 8086 microprocessor has six flag registers, which, depending on the situation, get set (1) or reset (0) after either 8-bit or 16-bit action. These flags are status and conditional. Five of these flags are identical to those found in an 8085 CPU, and they all function similarly. The overflow flag is the sixth one.
• Here are the 6 status flags:
• Post a flag (S)
• Null Flag (Z)
• Parity Flag (P) Carry Flag (AC) Auxiliary Carry Flag (CY)
• Here is a definition of the first five flags.
• If the outcome of a signed operation is too large to fit in the number of bits available to represent it, the overflow flag (O) will be set to (1); otherwise, it will be reset to (0). Following each operation, the overflow flag is set, or 1, if D [6] generates any carry and sends it to D [7] OR if D [6] does not generate any carry but D [7] does, then. The overflow flag is reset to 0 or does not exist if D [6] and D [7] both produce carry or neither do.
• Example: The result of adding bytes 100 + 50 is not inside the range -128–127.

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