Re: [RFC PATCH v2] hw/display/tcx: Allow 64-bit accesses to framebuffer stippler and blitter

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

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Le sam. 29 août 2020 18:14, Michael <macallan1888@gmail.com> a écrit :

> Hello,
>
> since I wrote the NetBSD code in question, here are my 2 cent:
>
> On Sat, 29 Aug 2020 08:41:43 -0700
> Richard Henderson <richard.henderson@linaro.org> wrote:
>
> > On 8/22/20 7:21 AM, Philippe Mathieu-Daudé wrote:
> > > The S24/TCX datasheet is listed as "Unable to locate" on [1].
>
> I don't have it either, but someone did a lot of reverse engineering
> and gave me his notes. The hardware isn't that complicated, but quite
> weird.
>
> > > However the NetBSD revision 1.32 of the driver introduced
> > > 64-bit accesses to the stippler and blitter [2]. It is safe
> > > to assume these memory regions are 64-bit accessible.
> > > QEMU implementation is 32-bit, so fill the 'impl' fields.
>
> IIRC the real hardware *requires* 64bit accesses for stipple and
> blitter operations to work. For stipples you write a 64bit word into
> STIP space, the address defines where in the framebuffer you want to
> draw, the data contain a 32bit bitmask, foreground colour and a ROP.
> BLIT space works similarly, the 64bit word contains an offset were to
> read pixels from, and how many you want to copy.
>

Thanks Michael for this information!
If you don't mind I'll amend it to the commit description so there is a
reference for posterity.

I'm waiting for *Andreas Gustafsson to test it then will repost.*


> have fun
> Michael
>

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