Re: Arguments for a sane ISA 6-years later

BGB <cr88192@gmail.com> writes:

Some amount of the cases where consistency issues have come up in my
case have do do with RAM-backed hardware devices, like the rasterizer
module. It has its own internal caches that need to be flushed, and not
flushing caches (between this module and CPU) when trying to "transfer"
control over things like the framebuffer or Z-buffer, can result in
obvious graphical issues (and, texture-corruption doesn't necessarily
look good either).

The approach taken on AMD64 CPUs is to have different memory types
(and associated memory type range registers).  Plain DRAM is
write-back cached, but there is also write-through and uncacheable
memory.  For a frame buffer that is read by some hardware that can
access the memory independently, write-through seems to be the way to
go.

- anton
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>