What is a flag in a microprocessor?
Flags are a modified kind of register that record the condition of a microprocessor’s calculation. For instance, a “zero status” flag is activated only when the microprocessor’s calculation concludes with a “zero” status.
What is status flag bit?
Individual bits in the FLAGS register give information about the status of the processor. Status flags – reflect the results of computations (add, subtract, multiply, divided) executed by the processor. Zero flag (ZF) – the zero flag is set(1) when the result of an arithmetic operation is zero.
What is the function of status flag register in microprocessor?
The FLAGS register is the status register that contains the current state of a CPU. The size and meanings of the flag bits are architecture dependent. It usually reflects the result of arithmetic operations as well as information about restrictions placed on the CPU operation at the current time.
What are status flags in 8086?
8086 has 16-bit flag register, and there are 9 valid flag bits….Status Flags.
| Flag Bit | Function |
|---|---|
| P | This is even parity flag. When result has even number of 1, it will be set to 1, otherwise 0 for odd number of 1s |
| CY | This is carry bit. If some operations are generating carry after the operation this flag is set to 1 |
What are the status flags in 8085?
In 8085 microprocessor, the flags register can have a total of eight flags. Thus a flag can be represented by 1 bit of information. But only five flags are implemented in 8085….And they are:
- Carry flag (Cy),
- Auxiliary carry flag (AC),
- Sign flag (S),
- Parity flag (P), and.
- Zero flag (Z).
Which is not a status flag in microprocessor?
Which of the following is not a status flag in microprocessor? Explanation: Overflow flag represents whether the result is out of scope or not. Direction flag is used in string operations and interrupt flag is used to enable the interrupts.
What is status register in microprocessor?
The status register is a hardware register that contains information about the state of the processor. Individual bits are implicitly or explicitly read and/or written by the machine code instructions executing on the processor.
How many flags are there in microprocessor?
(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.
What is the function of status register?
The status register lets an instruction take action contingent on the outcome of a previous instruction. Typically, flags in the status register are modified as effects of arithmetic and bit manipulation operations. For example, a Z bit may be set if the result of the operation is zero and cleared if it is nonzero.
Which are the flags of status register?
Common flags
| Flag | Name |
|---|---|
| Z | Zero flag |
| C | Carry flag |
| S / N | Sign flag Negative flag |
| V / O / W | Overflow flag |
Which of the following is not a status flag in microprocessor?
24. Which of the following is not a status flag in microprocessor? Explanation: Overflow flag represents whether the result is out of scope or not.
What are the various status flags provided in 8085?
What is the Z flag?
International maritime signal flag In the system of international maritime signal flags, part of the International Code of Signals, the Z flag stands for the letter Z (“Zulu” in the NATO Alphabet) when used in letter-by-letter alphabetic communication.
What is the purpose of status flags?
Status flags enable an instruction to act based on the result of a previous instruction. In pipelined processors, such as superscalar and speculative processors, this can create hazards that slow processing or require extra hardware to work around them.
What is the status register in 8085 microprocessor?
All the flags are present in an 8-bit register called as status register or flags register. The flags generally reflect the status of arithmetic or logical operations. In 8085, 5 flags are definite at the definite bit of flag register. Figure 1 shows the bit positions reserved for these flags in the flag register. Figure 1
What is flag in microprocessor?
What is flag in microprocessor? The Flag register is a Special Purpose Register which shows the status of the task. This is an 8-bit register but the only 5bit is used for the operation.
What happens when the directional flag is reset in microprocessor?
If directional flag is reset (0), then access the string data from lower memory location towards higher memory location. Interrupt Flag (I) – This flag is for interrupts. If interrupt flag is set (1), the microprocessor will recognize interrupt requests from the peripherals.
What is the difference between interrupt flag 1 and 0?
If interrupt flag is set (1), the microprocessor will recognize interrupt requests from the peripherals. If interrupt flag is reset (0), the microprocessor will not recognize any interrupt requests and will ignore them. Trap Flag (T) – This flag is used for on-chip debugging.