X-Git-Url: https://oss.titaniummirror.com/gitweb?a=blobdiff_plain;f=gmp%2Fmpn%2Fmips64%2FREADME;fp=gmp%2Fmpn%2Fmips64%2FREADME;h=65a1af16682477259676b54a6823b36e1e6131d3;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=0000000000000000000000000000000000000000;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/gmp/mpn/mips64/README b/gmp/mpn/mips64/README new file mode 100644 index 00000000..65a1af16 --- /dev/null +++ b/gmp/mpn/mips64/README @@ -0,0 +1,49 @@ +Copyright 1996 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 3 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. + + + + + +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. + +4. The R1x000 processors can issue one floating-point operation, two integer + operations, and one memory operation per cycle. The FPU has very short + latencies, while the integer multiply unit is non-pipelined. We should + therefore write fp based mpn_Xmul_1. + +STATUS + +Good...