From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001 From: Duncan Wilkie Date: Sat, 18 Nov 2023 06:11:09 -0600 Subject: Initial commit. --- gmp-6.3.0/mpn/sparc32/README | 71 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 gmp-6.3.0/mpn/sparc32/README (limited to 'gmp-6.3.0/mpn/sparc32/README') diff --git a/gmp-6.3.0/mpn/sparc32/README b/gmp-6.3.0/mpn/sparc32/README new file mode 100644 index 0000000..f2dd116 --- /dev/null +++ b/gmp-6.3.0/mpn/sparc32/README @@ -0,0 +1,71 @@ +Copyright 1996, 2001 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 either: + + * 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. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +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 General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. + + + + + +This directory contains mpn functions for various SPARC chips. Code that +runs only on version 8 SPARC implementations, is in the v8 subdirectory. + +RELEVANT OPTIMIZATION ISSUES + + Load and Store timing + +On most early SPARC implementations, the ST instructions takes multiple +cycles, while a STD takes just a single cycle more than an ST. For the CPUs +in SPARCstation I and II, the times are 3 and 4 cycles, respectively. +Therefore, combining two ST instructions into a STD when possible is a +significant optimization. + +Later SPARC implementations have single cycle ST. + +For SuperSPARC, we can perform just one memory instruction per cycle, even +if up to two integer instructions can be executed in its pipeline. For +programs that perform so many memory operations that there are not enough +non-memory operations to issue in parallel with all memory operations, using +LDD and STD when possible helps. + +UltraSPARC-1/2 has very slow integer multiplication. In the v9 subdirectory, +we therefore use floating-point multiplication. + +STATUS + +1. On a SuperSPARC, mpn_lshift and mpn_rshift run at 3 cycles/limb, or 2.5 + cycles/limb asymptotically. We could optimize speed for special counts + by using ADDXCC. + +2. On a SuperSPARC, mpn_add_n and mpn_sub_n runs at 2.5 cycles/limb, or 2 + cycles/limb asymptotically. + +3. mpn_mul_1 runs at what is believed to be optimal speed. + +4. On SuperSPARC, mpn_addmul_1 and mpn_submul_1 could both be improved by a + cycle by avoiding one of the add instructions. See a29k/addmul_1. + +The speed of the code for other SPARC implementations is uncertain. -- cgit v1.2.3