diff options
| -rw-r--r-- | mpn/cray/README | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/mpn/cray/README b/mpn/cray/README index 145a2af72..14d7a006e 100644 --- a/mpn/cray/README +++ b/mpn/cray/README @@ -63,7 +63,7 @@ max allowed vn 2097152 number of multiplies 16 -IDEAS: +IDEA: * Rewrite mpn_add_n: short cy[n + 1]; #pragma _CRI ivdep @@ -91,3 +91,13 @@ IDEAS: and 2, and generate cy[]. Then add operand 3 to the partial result, and accumulate carry into cy[]. Finally propagate carry just like in the new mpn_add_n. + +IDEA: + +Store fewer bits, perhaps 62, per limb. That brings mpn_add_n time +down to 2.5 cycles/limb and mpn_addmul_1 times to 4 cycles/limb. By +storing even fewer bits per limb, perhaps 56, it would be possible to +write a mul_mul_basecase that would run at effectively 1 cycle/limb. +(Use VM here to better handle the romb-shaped multiply area, perhaps +rouding operand sizes up to the next power of 2.) + |