| Flag Name | Z Zero flag | C Carry flag | S / N Sign flag Negative flag | V / O / W Overflow flag |
|---|
How many flags are in the status register?
Computer Architecture
The flag register holds a collection of
16 different conditions
. Table 14.1 outlines the most used flags. Contains the carry from the most significant bit (left hand bit) following a shift, rotate or arithmetic operation.
Which are the flags of status register are most likely to?
The answer to your query is the Z flags. It is the Z flags of status register are most likely to get
affected by the single cycle increment and decrement instructions
. Hope this helps!
What is flag register and its types?
The flag register is one of the
special purpose register
. The flag bits are changed to 0 or 1 depending upon the value of result after arithmetic or logical operations. 8086 has 16-bit flag register, and there are 9 valid flag bits. The format of flag register is like below.
Which are different flags in PSW register?
| CY PSW.7 Carry Flag | RS0 PSW.3 Register Bank selector bit 0 | OV PSW.2 Overflow Flag | – PSW.1 User definable FLAG |
|---|
What is the purpose of a 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.
What is difference between carry and auxiliary carry flag?
The auxiliary carry flag
AF watches for a 4-bit (nibble) carry
, while the common carry flag CF watches for a carry-out from the MSB of the operand size.
What are the commonly used condition code flags?
Processor status is described as condition codes, or status flags. Condition codes refer to the information about
most recently executed instruction
. For example, if decrementing a register produces zero value, the zero flag ZF is set by the processor. (A programmer might say: zero condition has occurred.)
Which register is used to check the flag in pic?
The flag register in the PIC is called
the status register
. The status register is an 8-bit register. It is also referred to as the flag register.
Which is the only register that can give memory address?
In a computer, the
memory address register (MAR)
is the CPU register that either stores the memory address from which data will be fetched to the CPU, or the address to which data will be sent and stored.
What is Flag register with example?
In our previous Example 1, as the 8-bit result 38H = 0011 1000 has three numbers of 1’s, so having odd number of 1’s, the parity flag is reset to 0. On the other hand, in Example 2, as the 8-bit result A3H = 1010 0011 has four numbers of 1’s (so an even number of 1’s), the parity flag is set to 1.
What are the different types of registers?
- MAR Register. The full form of MAR is the memory address register. …
- MDR. The full form of MDR register is a memory data register. …
- MBR. The full form of MBR is the memory buffer register. …
- PC. The full form of PC is the program counter register. …
- Accumulator. …
- Index Register. …
- Instruction Register.
What is meant by flag register?
The FLAGS register is
the status register that contains the current state of the CPU
. The size and meanings of the flag bits are architecture dependent. … The carry, parity, adjust, zero and sign flags are inherited from an earlier architecture, 8080 and 8085.
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 the use of accumulator register?
All microprocessors make use of an accumulator register
that can supply one number for an action, and where the result of an action will also be stored
. The size of the accumulator in terms of bits is used as a measure of the data unit capability of the microprocessor (as 8-bit, 16-bit, 32-bit, 64-bit, and so on).
Why flag is also called PSW?
PSW (program status word) register
The two unused bits are user-definable flags
. Four of the flags are called conditional flags, meaning that they indicate some conditions that result after an instruction is executed. These four are CY (carry), AC (auxiliary carry), P (parity), and OV (overflow).
