Re: [hatari-devel] floppy issue

[David Savinkoff <dsavnkff@xxxxxxxxx>]

----- Nicolas Pomarède wrote:
> Le 17/02/2014 03:31, David Savinkoff a écrit :
> > ----- Thomas Huth wrote:
> 
> >> The only related change to the DMA status that I can see is this patch
> >> here:
> >>
> >>   http://hg.tuxfamily.org/mercurialroot/hatari/hatari/rev/f84eb81fa309
> >>
> >> Nicolas, any ideas what could be wrong here?
> >>
> >>   Thomas
> >
> > Hi,
> >
> > Here is a patch that assumes the DMA error is transient.
> > EmuTOS works with this patch.
> >
> 
> Hello
> 
> calling "FDC_SetDMAStatus ( false )" outside of FDC_DMA_FIFO_Pull() 
> should not be required as DMA Status is completely handled in 
> FDC_DMA_FIFO_Push() and FDC_DMA_FIFO_Pull().
> 
> Except there was a bug in FDC_DMA_FIFO_Pull() and FDC_DMA.SectorCount 
> was set to 0 too early (when the last 16 bytes need to be transferred), 
> resulting in DMA.Status being set to "error", but also forcing the last 
> 15 bytes of each sector to 0, which would seriously damage any disk :(
> 
> This is now fixed and hopefully no one damaged some ST/MSA images.
> 
> Nicolas
> 

Hi Nicolas,

1) An unsigned compare for less than zero produces the compiler warning:

hatari/src/fdc.c: In function ‘FDC_DMA_FIFO_Pull’:
hatari/src/fdc.c:981: warning: comparison is always false
due to limited range of data type

2) I noticed that FDC_DMA_FIFO_Push() and FDC_DMA_FIFO_Pull()
now have different conditions for similar sections of code.

FDC_DMA_FIFO_Push() has:
if ( FDC_DMA.BytesInSector <= 0 )
and
FDC_DMA_FIFO_Pull() has:
if ( FDC_DMA.BytesInSector < 0 )

Sincerely,
David Savinkoff