Those things about CPU registers (4)-flag register

Flag register-stores a lot of flag bits, which identify a series of states during the execution of instructions by the CPU. These flags are basically automatically set and modified by the CPU. We only need to understand or remember it (except for hardware or cpu gods)

CF carry flag

PF parity flag

ZF zero flag

SF symbol mark

OF complement overflow flag

TF trace flag

IF interrupt flag

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Under the x64 architecture, the original eflags register is upgraded to 64-bit rflags, but the expanded upper 32 bits are not currently used.