T3/T3 mul_2 and addmul_2

[David Miller]

From: Torbjorn Granlund <tg at gmplib.org>
Date: Fri, 08 Mar 2013 13:41:01 +0100

> I reverted to the version I sent you, then tested your operands, as will
> as a trillion other operands.  The code works perfectly with my
> emulation of the umulxhi, addxc, and addxccc...
> 
> Then I re-read the documentation, ad stared at the *mul_2 code as well
> as the emulation code.  All looked good.

Seems to work fine, here are some speed runs:

davem at patience:~/src/GMP/HG/build-sparc64-ultrasparct4/tune$ ./speed -C -s 32-64 -t 2 mpn_mul_2
overhead 6.06 cycles, precision 10000 units of 3.51e-10 secs, CPU freq 2847.34 MHz
            mpn_mul_2
32             7.7564
34             7.5137
36             7.7395
38             7.4933
40             7.7088
42             7.4566
44             7.7251
46             7.4409
48             7.6494
50             7.4467
52             7.6216
54             7.4067
56             7.5927
58             7.3858
60             7.6043
62             7.4039
64             7.5909
davem at patience:~/src/GMP/HG/build-sparc64-ultrasparct4/tune$ ./speed -C -s 32-64 -t 2 mpn_addmul_2
overhead 6.04 cycles, precision 10000 units of 3.51e-10 secs, CPU freq 2847.46 MHz
         mpn_addmul_2
32             8.5508
34             8.4938
36             8.6271
38             8.4753
40             8.4031
42             8.4429
44             8.3950
46             8.4700
48             8.3910
50             8.4448
52             8.4181
54             8.4581
56             8.3765
58             8.4279
60             8.3778
62             8.4242
64             8.3734