POPF             POP Flags from the Stack            Flags: O D I T S Z A P C
                                                            r r r r r r r r r
          Logic:    flag-register . (SP)
                    SP . SP + 2

    POPF transfers the word at the top of the stack to the flags register,
    replacing the old flags, then increments SP by 2 to point to the new
    top of stack.

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   Operands                  Clocks   Transfers  Bytes   Example
   no operands                 12         1        1     POPF
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