Replacing "redc"

[paul zimmermann]

quite interesting. Is the API of the new interface fixed? I'd like to try it
with GMP-ECM, where we currently use the redc_* internal functions. For example
on my machine Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz, running at 3499.804Mhz:

$ ./bench_mulredc -v
...
Time in microseconds per call, size=8 (iter=1807889):
mpn_mul_n  = 0.055
mpn_sqr    = 0.042
mpn_redc_1 = 0.069 *
mpn_redc_2 = 0.077
mpn_redc_n = disabled

mulredc    = 0.124
mul+redc_1 = 0.122 *
mul+redc_2 = 0.135
mul+redc_n = disabled

mulredc    = 0.124
sqr+redc_1 = 0.108 *
sqr+redc_2 = 0.122
sqr+redc_n = disabled
mulredc1   = 0.013

Paul