WH Tan <PICLIST@mitvma.mit.edu> wrote:

> I read from datasheet regarding OV flag.
>
> "This bit is used for signed arithmetic. It indicates an overflow
> of the 7-bit magnitude, which causes the sign bit to change."
>
> Is that mean whenever the MSB toggled (not include the result from
> bsf & bcf), this flag will be set?

No.  The Overflow flag indicates that the result is too large to fit
in 8 bits; it should be set whenever:

    1.  There was an internal carry generated between bit 6 and bit 7
        of the result, but NO carry was generated out of bit 7 of
        the result.

        OR

    2.  There was NO internal carry generated between bit 6 and bit
        7 of the result, but there WAS a carry generated out of bit
        7.

-Andy

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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