Tim Bird wrote:
Roman Zippel wrote:
On Sun, 25 Sep 2005, Thomas Gleixner wrote:
Can you please point out which architectures do not have a 32x32->64
instruction ?
<snip>
For the rest you might want to check <asm/div64.h>, if div64 has to be
emulated, there are good chances this instruction has to be emulated as
well (especially in smaller embedded archs).
Hmmm. In my experience, there are several embedded platforms
with a 32x32->64 instruction, which are lacking a div64 instruction.
I don't think checking for div64 is a very good metric here.
Also, even having a div64 instruction does not eliminate the asm/div64.h
as it checks for results that are >32-bits and does the right thing.
For example, letting the x86 do this divide with such a result, results
in a trap.
This is why we need to be very careful where we use the div_ll_l_rem()
which accesses just this instruction.
--
George Anzinger [email protected]
HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/
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