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

[tim lindner]

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."