This file contains elementary context related functions used to

This file contains elementary context related functions used to
save and restore "sets" of registers in various places.
The restorectx and swapctx functions are used by cpu_switch()
and deal with the special registers, as well as the preserved
registers.
The *callee_saved* functions are used to save and restore the
preserved registers (integer and floating-point). They are
useful for signal delivery and ptrace support.
The save_high_fp and restore_high_fp functions are used to
"load" and "unload" to and from the CPU as part of lazy context
switching.
The ia32 specific context functions have been kept with the ia32
code.

Approved by: re@ (blanket)