What is the purpose of a zero flag?
What is the purpose of a zero flag?
Along with a carry flag, a sign flag and an overflow flag, the zero flag is used to check the result of an arithmetic operation, including bitwise logical instructions. It is set to 1, or true, if an arithmetic result is zero, and reset otherwise.
What is the zero flag in assembly?
The Zero flag indicates that an operation produced zero. For example, if an operand is subtracted from another of equal value, the Zero flag is set. The Sign flag indicates that an operation produced a negative result. If the most significant bit of the destination operand is set, the Sign flag is set.
Which flag is set when ALU generates complete zero result?
Assertion (A): In 8085, the zero flag is set when ALU operation results in 0. If the result is not 0, this flag is reset.
How can you tell a zero flag?
Zero flag (ZF) – the zero flag is set(1) when the result of an arithmetic operation is zero. Sign flag (SF) – the sign flag is set(1) when the result of an arithmetic operation has a 1 in the most significant bit (msb)….
| Status Flags | Flag Set (1) | Flag Clear (0) |
|---|---|---|
| ZF | ZR | NZ |
| SF | NG | PL |
| OF | OV | NV |
What is JZ in microprocessor?
Microprocessor8085. In 8085 Instruction set, we are having one mnemonic JZ a16, which stands for “Jump Zero” and “a16” stands for any 16-bit address. This instruction is used to jump to the address a16 as provided in the instruction.
What does 0 mean in assembly?
%0 is just the first input/output operand defined in your code. In practice, this could be a stack variable, a heap variable or a register depending on how the assembly code generated by the compiler.
What is XOR in assembly?
The XOR instruction performs a bit wise Exclusive OR operation between corresponding bits in the two operands and places the result in the first operand.
When a zero flag is set and a carry flag is set during an ALU operation of a microprocessor?
Zero Flag (Z) The zero flag is set (i.e. becomes 1) when the ALU operation results in 0, and the flag is reset (i.e. becomes 0) if the result is nonzero. This flag is affected by the results in the accumulator as well as in the other registers.
Which flag is reset when flag register content is d4h?
Answer: Explanation: In 8085 microprocessor, flag register consists of 8 bits and only 5 of them are useful. These set of instructions will reset the sign flag to 0 as 40 – 30 is a positive number.
What is JZ and JNZ?
3. 137. JE and JZ are just different names for exactly the same thing: a conditional jump when ZF (the “zero” flag) is equal to 1. (Similarly, JNE and JNZ are just different names for a conditional jump when ZF is equal to 0.)
What does LXI mean in 8085?
We can use this instruction to load data from memory location using the memory address, which is stored in the register pair rp. For an example, if the instruction is LXI H, FE50. It means that the FE50 is loaded into the HL register pair.
When the Z bit is 0 What is the result of 0?
Flag-Setting Example
| Flag | Explanation |
|---|---|
| N = 0 | The result is 0, which is considered positive, and so the N (negative) bit is set to 0 . |
| Z = 1 | The result is 0, so the Z (zero) bit is set to 1 . |
| C = 1 | We lost some data because the result did not fit into 32 bits, so the processor indicates this by setting C (carry) to 1 . |
What is flag register in microprocessor?
The Flag register is a Special Purpose Register. Depending upon the value of result after any arithmetic and logical operation the flag bits become set (1) or reset (0). In 8085 microprocessor, flag register consists of 8 bits and only 5 of them are useful. The 5 flags are:
What is a zero flag in 8085 microprocessor?
Answer Wiki. A zero flag is used in 8085 to indicate that the arithmetic or logical operation resulted to a zero. It is located at the 6th bit in flag register.
What is the flag register in 8085?
Flag register in 8085 microprocessor. The Flag register is a Special Purpose Register. Depending upon the value of result after any arithmetic and logical operation the flag bits become set (1) or reset (0). In 8085 microprocessor, flag register consists of 8 bits and only 5 of them are useful.
Where is the zero flag located in a microcontroller?
It is located at the 6th bit in flag register. The zero flag is typically used along with jump instruction to check when a counter elapses so as to allow looping in assembly code. For example a piece of code has to be executed 5 times, a counter is set of 5 and the code which is to be looped is written.
