[Coco] Apparent discrepancy between MAME and XRoar re: SBCB instruction

[Ron Klein]

Hi Tim,

Great to see you are still around!  I was asking Boisy about you at Tandy
Assembly.  In any case, did you submit the your findings to mametesters?

Thanks

-Ron


On Tue, Oct 17, 2017 at 7:40 PM, tim lindner <tlindner at macmess.org> wrote:

> On Tue, Oct 17, 2017 at 4:22 PM, Pierre Sarrazin <sarrazip at sarrazip.com>
> wrote:
> > On MAME 0.158, it's 7 while on XRoar, it's 5.
>
> Here is the code in MASTER branch of MAME:
>
> SBC8:
> m_temp.w = (uint16_t)read_operand() + (m_cc & CC_C ? 1 : 0);
> regop8() = set_flags(CC_NZVC, regop8(), m_temp.b.l, regop8() - m_temp.w);
> return;
>
>
> Operand plus carry? It seems you found a legitimate bug.
>
>
>
> <https://github.com/mamedev/mame/blob/master/src/devices/
> cpu/m6809/base6x09.ops#L241>
>
> --
> --
> tim lindner
>
> "Proper User Policy apparently means Simon Says."
>
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