tree af18c33b645df4ceac47899f0b82c73101ce32ad
parent 68c18d1ccff03ef4763bd7c0cbb6fabc4fd761cb
author Artyom Tarasenko <atar4qemu@googlemail.com> 1281881081 +0200
committer Blue Swirl <blauwirbel@gmail.com> 1281894972 +0000

sparc escc IUS improvements (SunOS 4.1.4 fix)

According to scc_escc_um.pdf:
 - Reset Highest IUS must update irq status to allow processing
   of the next priority interrupt.
 - rx interrupt has always higher priority than tx on same channel

The documentation only explicitly says that Reset Highest IUS
command (0x38) clears IUS bits, not that it clears the corresponding
interrupt too, so don't clear interrupts on this command.

The patch allows SunOS 4.1.4 to use the serial ports

Signed-off-by: Artyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>