1Copyright 1996 Free Software Foundation, Inc. 2 3This file is part of the GNU MP Library. 4 5The GNU MP Library is free software; you can redistribute it and/or modify 6it under the terms of either: 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at your 10 option) any later version. 11 12or 13 14 * the GNU General Public License as published by the Free Software 15 Foundation; either version 2 of the License, or (at your option) any 16 later version. 17 18or both in parallel, as here. 19 20The GNU MP Library is distributed in the hope that it will be useful, but 21WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 22or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 23for more details. 24 25You should have received copies of the GNU General Public License and the 26GNU Lesser General Public License along with the GNU MP Library. If not, 27see https://www.gnu.org/licenses/. 28 29 30 31 32 33This directory contains mpn functions optimized for MIPS3. Example of 34processors that implement MIPS3 are R4000, R4400, R4600, R4700, and R8000. 35 36RELEVANT OPTIMIZATION ISSUES 37 381. On the R4000 and R4400, branches, both the plain and the "likely" ones, 39 take 3 cycles to execute. (The fastest possible loop will take 4 cycles, 40 because of the delay insn.) 41 42 On the R4600, branches takes a single cycle 43 44 On the R8000, branches often take no noticeable cycles, as they are 45 executed in a separate function unit.. 46 472. The R4000 and R4400 have a load latency of 4 cycles. 48 493. On the R4000 and R4400, multiplies take a data-dependent number of 50 cycles, contrary to the SGI documentation. There seem to be 3 or 4 51 possible latencies. 52 534. The R1x000 processors can issue one floating-point operation, two integer 54 operations, and one memory operation per cycle. The FPU has very short 55 latencies, while the integer multiply unit is non-pipelined. We should 56 therefore write fp based mpn_Xmul_1. 57 58STATUS 59 60Good... 61