| Implementation | Optimisation | Cycles | Code size | Stack usage |
|---|---|---|---|---|
| donna | -Os |
15748K | 7.4KB | 3148B |
| donna | -O2 |
15218K | 7.9KB | 3148B |
| donna | -O3 |
12907K | 16KB | 3380B |
| naclref | -Os |
47813K | 3.2KB | 4012B |
| naclref | -O2 |
34309K | 3.5KB | 4036B |
| naclref | -O3 |
35059K | 4.1KB | 4044B |
| tweetnacl | -Os |
75979K | 2.8KB | 2244B |
| tweetnacl | -O2 |
68876K | 3.0KB | 2268B |
| tweetnacl | -O3 |
69622K | 8.9KB | 2900B |
naclref at -O2 seems to give a good balance. If you can spare the flash, donna is quite significantly quicker.