On recent u-boots, the watchdog is turned on / left enabled. The
Beaglebone Black rev. C ships with such a u-boot internally so any
application booting from it must disable the watchdog.
Therefore this change is needed to boot an RTEMS app out-of-the-box
on a BBB Rev C - otherwise the user button must be held during boot
(to bypass the stock uboot) or the internal uboot must be updated. To
allow for a better out-of-the-box experience, we just turn off the
watchdog.
* Coding style cleanups.
* Use OS reserved trap 0x89 for IRQ Disable
* Use OS reserved trap 0x8A for IRQ Enable
* Add to SPARC CPU supplement documentation
This will result in faster Disable/Enable code since the
system trap handler does not need to decode which function
the user wants. Besides the IRQ disable/enabled can now
be inline which avoids the caller to take into account that
o0-o7+g1-g4 registers are destroyed by trap handler.
It was also possible to reduce the interrupt trap handler by
five instructions due to this.
Save five instructions on underflow handling.
By using an optimized trap entry we can move instructions from
the window underflow function into the trap entry vector. By
setting WIM=0 and using RESTORE it is possible to move the
new WIM register content from the trapped window into the
to-be-restored register window. It is then possible to avoid
the WIM write delay.
By using a optimized trap entry we can move instructions from
the window overflow function into the trap entry vector. By
using the saved locals instead of g1 we don't need to save
that register temporarily. Also spead out non store instructions
inbetween stores to use the write buffer better.
Make sure also the size is cache aligned since otherwise we may have
some overlap with the next allocation block. A cache invalidate on this
area would be fatal.
sparc64_install_isr_entries function is no longer used. Removing it also
allows to use the default bsppredriverhook for usiii and bspstart for niagara.
