Re: [hatari-devel] Strange behaviour with ROL.B ?

[Laurent <laurent.sallafranque@xxxxxxx>]

I agree.

But under Hatari, it's often set instead of clear.

Laurent

Le 28/06/2020 à 10:14, Thorsten Otto a écrit :

On Sonntag, 28. Juni 2020 10:04:04 CEST Laurent wrote:

> rol.b d0 by $40 (if carry bit is set, add 2 to d7)

 

From the manual:

 

2. Register—The rotate count is the value in the data register specified in the instruction, modulo 64.

 

and:

 

C — Set according to the last bit rotated out of the operand; cleared when the rotate count is zero.

 

So in your example, rol by $40 will actually use a count of zero, and the carry flag should always be cleared.