This directory contains code for AMD bulldozer including its piledriver update.

We currently make limited use of SIMD instructions, both via the MPN_PATH and

via inclusion of x86_64/fastsse files.

The bd1 cores share one SIMD/FPU pipeline for two integer units.  This probably

means that an all-core GMP load (such as a HPC load) might run slower if there

is significant SIMD dependency.

We should perhaps allow a special 'bd1nosimd' pseudo cpu-name excluding any

SIMD code.