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Why does 8085 microprocessor has 8 bit flag register when it has only 5 flags?
Adssmile
The 8085 microprocessor has an 8-bit flag register, even though it only has 5 flags, because all of the registers in the 8085 are 8-bit or 16-bit. In fact, the flags register is considered to be part of the accumulator, as one "register pair", for purposes of stack push/pop and interrupt call/return.
Be warned, however, that you should not attempt to change the state of bits stored on the stack and then pop'ing them into AF, because some of the three "unused" bits might be undocumented but actually used, or their meaning might change between different versions of the chip.
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What is a flag in micro processor?
Flags are kind of register that record the condition of a microprocessor's calculation process.
What are the various flags used in 8085?
there are 5 flags of intel 8085 are: Carry flag(CY), parity flag(P), Auxiliary Carry flag(AC), Zero Flag(Z), Sign flag(S).
What is the importance of flags in microprocessor?
sign flag parity flag zero flag
Explain different types of flags in 8085 microprocessor?
Flags are microprocessor dependent. ie flags are different for different microprocessors. Flag represents the status ( & Type) of the operation performed. Ex: In terms of 8085 we have 5 flags : Zero, Carry, Ac Carry, Parity, Sign Flag register is of 8 bits in this case. These flags can also be used for logic implementation.
What is the purpose of adc instruction according to 8085 microprocessor?
this instruction is used to add the specified register content to that of the accumulator along with the carry flag value. this instruction is used in processes which involve continuous addition.
Microprocessor PREVIOUS question papers for bca 2nd year IN MADRAS UNiversity?
PART - A 10*3=30 1. Define Micro Processor. 2. What is an accumulator. 3. Why Data Bus id Bidirectional? 4. What is Microcomputer? Explain the difference between a microprocessor and microcomputer 5. List the applications of micro computer. 6. What are the advantages of microprocessor based system? 7. Explain the functions of IO/Min 8085. 8. What is Flag? List the flag of 8085. Show the bit positions of various flags in 8085 flag register? 9. Why Address Bus is unidirectional? 10. What are the Interrupts in 8085? PART - B 5*6=30 11. What are Data Transfer Instructions, Write any Instruction. 12. Define the following Terms Compiler, Assembler, Interpreter with example 13. Explain Instructions & Data Format. 14. Explain & Draw a Block Diagram of Computer with the microprocessor as CPU. 15. Explain the Logical Operations. PART - C 4*10=40 16. Explain the Microprocessor Architecture and its operations 17. Explain the various pins of 8085 Microprocessor 18. List the Registers in the 8085 Microprocessor & explain the functions in detail 19. Write a Assembly language program to add two 8 bit numbers 20. Write a Assembly language program to add 16 bit numbers
Show the bit positions of various flags in 8085 flag register?
The 8085 microprocessor has 5 flags: 1. Zero flag: The zero flag is set, when the ALU operation results a zero . 2. Carry flag: If an arithmetic operations results in a carry, this flag is set. 3. Parity flag: This flag is set, when an arithmetic or logical operation results in a data, which has even number of 1s. If otherwise, it is reset. 4. Sign flag: After the execution of an arithmetic or logic operations, if D7 bit of the accumulator is 1, it indicates a negative number and this flag is set. If otherwise, it is reset. 5. Auxiliary Carry flag: used for BCD Operations, During the BCD operations, if D3 bit producing the carry then the AC bit set as1, otherwise the bit is 0. 6. Carry Flag: when a carry is generated by digit D7, then the carry flag set as 1, otherwise the bit will be 0.
What Is The Flags Signals In Microprocessor?
Microprocessors are equipped with flags which are used for letting one know some information such as for instance whether the result of any operaton was positive or negative,the result contains the even parity bits or odd,whether carry bits are generated or not.all these help the programmer out in performing further opertaions.different microprocessors contain different types and differnet number of flags.for instance INTEL 8085 contains 5 flags. AUX CARRY FLAG,ZERO FLAG,SIGN FLAG,PARITY FLAG,CARRY FLAG Anand bhat(mca@kiit-870024)
Explain 8086 flag register?
FLAGS REGISTER="h2headingh3"style="color:rgb(0,0,0);"name="flags_register">Flags Register - determines the current state of the processor. They are modified automatically by CPU after mathematical operations and allow one to determine the type of the result as well as determine conditions to transfer control to other parts of the program. Generally you cannot access these registers directly.Carry Flag (CF) - this flag is set to 1 when there is an unsigned overflow. For example when you add bytes 255 + 1 (result is not in range 0...255). When there is no overflow this flag is set to 0.Parity Flag (PF) - this flag is set to 1 when there is even number of one bits in result, and to 0 when there is odd number of one bits.Auxiliary Flag (AF) - set to 1 when there is an unsigned overflow for low nibble (4 bits).Zero Flag (ZF) - set to 1 when result is zero. For non-zero result this flag is set to 0.Sign Flag (SF) - set to 1 when result is negative. When result is positive it is set to 0. (This flag takes the value of the most significant bit.)Trap Flag (TF) - Used for on-chip debugging.Interrupt enable Flag (IF) - when this flag is set to 1 CPU reacts to interrupts from external devices.Direction Flag (DF) - this flag is used by some instructions to process data chains, when this flag is set to 0 - the processing is done forward, when this flag is set to 1 the processing is done backward.Overflow Flag (OF) - set to 1 when there is a signed overflow. For example, when you add bytes 100 + 50 (result is not in range -128...127).
What is the difference between conditional and control flags in 8086 microprocessor?
Control Flag Register: The Control Flag Register (CFR), also known as the Program Status Word (PSW), is a register used to control the execution flow and behavior of the processor. It typically stores various control flags that govern different aspects of the CPU's operation. Some common flags found in the Control Flag Register include: Carry Flag (CF): Used to indicate whether an arithmetic operation generated a carry or borrow. Zero Flag (ZF): Indicates whether the result of an operation is zero. Sign Flag (SF): Indicates the sign (positive or negative) of the result. Overflow Flag (OF): Indicates whether an arithmetic operation resulted in an overflow. Interrupt Flag (IF): Determines whether interrupts are enabled or disabled. The Control Flag Register provides control over program execution, including branching, interrupt handling, and arithmetic operations. It helps determine the outcome of operations and can be used for conditional branching based on specific flag states. Conditional Flag Register: The Conditional Flag Register (CFR), also known as the Condition Code Register (CCR) or Status Register (SR), contains flags that reflect the result of the most recent arithmetic or logical operation performed by the processor. These flags are used to perform conditional branching and control the flow of instructions based on specific conditions. The flags present in the Conditional Flag Register can vary depending on the processor architecture, but some common flags include: Zero Flag (ZF): Indicates whether the result of an operation is zero. Sign Flag (SF): Indicates the sign (positive or negative) of the result. Overflow Flag (OF): Indicates whether an arithmetic operation resulted in an overflow. Carry Flag (CF): Used to indicate whether an arithmetic operation generated a carry or borrow. Auxiliary Carry Flag (AF): Indicates a carry or borrow from the lower-order nibble (4 bits) to the higher-order nibble. The Conditional Flag Register is primarily used for conditional jumps or branches, allowing the processor to alter the program flow based on the current flag states. To summarize, the Control Flag Register focuses on controlling the processor's behavior and handling interrupts, while the Conditional Flag Register reflects the outcome of arithmetic and logical operations and enables conditional branching based on flag states.
Conditional call and unconditional call all condition of 8085 microprocessor?
Calls Which are based on conditions like flag status are called conditional flags ex:cc(Call if carry) cz(Call if zero) Calls Which are independent of any kind of conditions, are called unconditional call Ex:Call 2030
How you can change value of flag register of 8086?
In general, the best way to change the flag register is to perform some operation that sets or clears flags. If you are careful, you can also push the flags onto the stack, manipulate the stored value, and then pop them back off. This is often the method used by a debugger to set the single step flag. When using this method, it is important to not set an inconsistent combination of flags.
