mirror of
git://git.gnupg.org/gnupg.git
synced 2024-11-04 20:38:50 +01:00
24 lines
760 B
Plaintext
24 lines
760 B
Plaintext
|
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...
|