On Tue, 2002-04-30 at 23:53, Leif Delgass wrote:
> On Tue, 30 Apr 2002, Jos� Fonseca wrote:
>
> > On 2002.04.30 22:07 Jos� Fonseca wrote:
> > > ... Next in mach64_drv.h, let's try the following definitions for the
> > > MMIO:
> > >
> > > #define MACH64_READ(reg) readl(MACH64_ADDR(reg))
> > > #define MACH64_WRITE(reg,val) writel(MACH64_ADDR(val, reg))
> > >
> >
> > Sorry, i've mistaken writting it. It's instead
> >
> > #define MACH64_READ(reg) readl(MACH64_ADDR(reg))
> > #define MACH64_WRITE(reg,val) writel(val, MACH64_ADDR(reg))
>
> There's a wrinkle for the vertex buffers though. The register offsets and
> data in the buffer have already been swapped to little-endian, whereas the
> state updates and such using the DMA* macros (which in turn use
> MACH64_WRITE) pass data to the macros in cpu endianess. So in the
> pseudo-DMA code in _dispatch_vertex, I changed the
>
> MACH64_WRITE(reg, *p++);
>
> to
>
> MACH64_DEREF(reg) = *p++;
Maybe better
MACH64_WRITE(le32_to_cpu(*p++), reg);
?
> because the value (*p) is already little-endian, whereas the register
> address has to be swapped from little-endian back to big-endian for the
> MMSELECT(reg). So wouldn't you have to swap the value back to big-endian
> as well in order to use this modified MACH64_WRITE macro?
Yes, but it's already done correctly AFAICS on mach64_state.c line 530:
reg = le32_to_cpu(*p++);
PS: http://www.byteswap.net/mikesnotes/2002/getting-started/ is a nice
introductory article about cross-platform lowlevel programming.
--
Earthling Michel D�nzer (MrCooper)/ Debian GNU/Linux (powerpc) developer
XFree86 and DRI project member / CS student, Free Software enthusiast
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