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.hender...@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. have fun Michael
