Contained within the PSW are the two bit condition code, representing zero, positive, negative, overflow, and similar flags of other architectures' status registers. Conditional branch instructions test this encoded as a four bit value, with each bit representing a test of one of the four condition code values, 2 3 + 2 2 + 2 1 + 2 0 .

May 21, 2023 · PSW register in 8051 microcontroller contains math flags and PCON contains general user flags. Math flags are grouped in PSW of microcontroller 8051 and they are Carry(C), Auxiliary Carry (AC), Over flow (OV), and Parity (P).

Four of the flags are called conditional flags, which means that they indicate a condition which results after an instruction is executed. These four are CY (Carry), AC (auxiliary carry), P (parity), and OV (overflow).

Nov 9, 2024 · The 8051 microcontroller’s Program Status Word (PSW) is a special function register that houses several important flags. These flags are single-bit indicators that provide valuable information about the state of the processor and the results of various operations.

The PSW.5 and PSW.l bits are general-purpose status flag bits and can be used by the programmer for any purpose. In other words, they are user definable. The following is a brief explanation of four of the flag bits of the PSW register.

P (parity flag): The parity flag reflect the number of 1's in the A (accumulator) register only; if the A register contains an odd number of 1's then p=1 therefore p=0 if A has an even number 1's. OV (overflow flag): This flag is set whenever the result of a signed number operation is too large causing the high order bit to overflow into the ...

In this tutorial one part of architecture PSW( program status word ) also known as Flag register of 8051 microcontrollers. Flag register in 8051 microcontroller is a 8-bit register and it is bit addressable ( refer previous tutorials for what is bit addressable ) .

• Four math flags that respond automatically to the outcomes of the math operations • Three general purpose user flags that can be set to 1 or cleared to 0 by the programmer

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.

Jul 2, 2013 · Although the PSW register is 8 bits wide, only 6 bits of it are used by the 8051. 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.