| This directory contains mpn functions optimized for MIPS3. Example of |
| processors that implement MIPS3 are R4000, R4400, R4600, R4700, and R8000. |
| |
| RELEVANT OPTIMIZATION ISSUES |
| |
| 1. On the R4000 and R4400, branches, both the plain and the "likely" ones, |
| take 3 cycles to execute. (The fastest possible loop will take 4 cycles, |
| because of the delay insn.) |
| |
| On the R4600, branches takes a single cycle |
| |
| On the R8000, branches often take no noticable cycles, as they are |
| executed in a separate function unit.. |
| |
| 2. The R4000 and R4400 have a load latency of 4 cycles. |
| |
| 3. On the R4000 and R4400, multiplies take a data-dependent number of |
| cycles, contrary to the SGI documentation. There seem to be 3 or 4 |
| possible latencies. |
| |
| STATUS |
| |
| Good... |
