How many flags does microprocessor 8085 have?
5 flags
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 are the various flag of 8085?
8085 has five flags. Sign flag, zero flag, Auxiliary carry flag, Parity flag and Carry flag.
How many flags are there in flag register?
8086 has 16-bit flag register, and there are 9 valid flag bits….Status Flags.
| Flag Bit | Function |
|---|---|
| CY | This is carry bit. If some operations are generating carry after the operation this flag is set to 1 |
| O | The overflow flag is set to 1 when the result of a signed operation is too large to fit. |
Which instruction does not affect the flag?
NOT instruction does not affect any flags! NEG instruction affects these flags only: CF, ZF, SF, OF, PF, AF. NOT – Reverse each bit of operand.
What is the difference between carry flag and overflow flag?
The difference between Carry and Overflow is that Carry is used for unsigned numbers whereas Overflow is used for signed numbers. Carry is detected when addition of two numbers becomes a smaller number than the input terms.
What will happen if the direction flag is set?
When the direction flag is set, the processor decrements the registers instead. This means you need to start with them pointing to the end of the memory block you’re copying. Instead of starting from the beginning and copying to the end, it starts at the end and copies backward until it gets to the beginning.
How can you tell a zero flag?
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.
When an auxiliary carry flag is cleared?
AC, the auxiliary carry flag If there is a carry from D3 to D4 during an ADD or SUB operation, this bit is set; otherwise, it is cleared. This flag is used by instructions that perform BCD (binary coded decimal) arithmetic. Flag 0 is a general-purpose flag available to the programmer.
What is overflow flag with example?
An example, suppose we add 127 and 127 using 8-bit registers. The overflow flag is thus set when the most significant bit (here considered the sign bit) is changed by adding two numbers with the same sign (or subtracting two numbers with opposite signs).
Why flag is called PSW?
The Program Status Word (PSW) contains status bits that reflect the current CPU state. The 8051 variants provide one special function register called PSW with this status information. The 251 provides two additional status flags, Z and N, that are available in a second special function register called PSW1.
What is full form of PSW?
The program status word (PSW) is a register that performs the function of a status register and program counter, and sometimes more.
What does PSW stand for in school?
PSW Education Abbreviation
| 3 | PSW | Personal Support Worker + 1 variant Medical, Government, Support |
|---|---|---|
| 1 | PSW | Pattern s of Strengths and Weaknesses Learning, School, Technology |
| 2 | PSW | Physician-Scientist Workforce Group, Report, Science |
| 2 | PSW | Polytechnic of the South West |
| 2 | PSW | Post Study Work + 1 variant Tier, Student, Study |
What does the flag indicate when rs1 1 and RS 0 1?
This flag is set whenever the result of a signed number operation is too large causing the high order bit to overflow into the sign bit. the carry flag is used to detect error in unsigned arithmetic operations….Welcome back.
| RS 1 | RS 0 | Register Bank |
|---|---|---|
| 0 | 1 | Register bank 1 |
| 1 | 0 | Register bank 2 |
| 1 | 1 | Register bank 3 |