hw/display/artist: rewrite vram access mode handling
When writing this code it was assumed that register 0x118000 is the
buffer access mode for color map accesses. It turned out that this
is wrong. Instead register 0x118000 sets both src and dst buffer
access mode at the same time.
This required a larger rewrite of the code. The good thing is that
both the linear framebuffer and the register based vram access can
now be combined into one function.
This makes the linux 'stifb' framebuffer work, and both HP-UX 10.20
and HP-UX 11.11 are still working.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: qemu-stable@nongnu.org
Signed-off-by: Helge Deller <deller@gmx.de>