[RFC] Port libitm to powerpc

[Joseph S. Myers]

On Thu, 1 Dec 2011, Iain Sandoe wrote:

> However, we (on Darwin) don't seem to save the FPSCR  - and there's no mention
> of it in "preserved regs" section of the ABI doc.  I wonder if that's an
> oversight.

As I previously noted in the ARM discussion, C specifically says that 
setjmp/longjmp should *not* save/restore floating-point exceptions and 
rounding modes.  Think of the floating-point state as being a global 
variable (well, thread-local).

-- 
Joseph S. Myers
joseph@codesourcery.com