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| hppa1_1 | ||
| hppa2_0 | ||
| add_n.asm | ||
| gmp-mparam.h | ||
| lshift.asm | ||
| pa-defs.m4 | ||
| README | ||
| rshift.asm | ||
| sub_n.asm | ||
| udiv.asm | ||
Copyright 1996, 1999, 2001, 2002, 2004 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 2.1 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; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. This directory contains mpn functions for various HP PA-RISC chips. Code that runs faster on the PA7100 and later implementations, is in the pa7100 directory. RELEVANT OPTIMIZATION ISSUES Load and Store timing On the PA7000 no memory instructions can issue the two cycles after a store. For the PA7100, this is reduced to one cycle. The PA7100 has a lookup-free cache, so it helps to schedule loads and the dependent instruction really far from each other. STATUS 1. mpn_mul_1 could be improved to 6.5 cycles/limb on the PA7100, using the instructions below (but some sw pipelining is needed to avoid the xmpyu-fstds delay): fldds s1_ptr xmpyu fstds N(%r30) xmpyu fstds N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) addc stws res_ptr addc stws res_ptr addib Loop 2. mpn_addmul_1 could be improved from the current 10 to 7.5 cycles/limb (asymptotically) on the PA7100, using the instructions below. With proper sw pipelining and the unrolling level below, the speed becomes 8 cycles/limb. fldds s1_ptr fldds s1_ptr xmpyu fstds N(%r30) xmpyu fstds N(%r30) xmpyu fstds N(%r30) xmpyu fstds N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) ldws N(%r30) addc addc addc addc addc %r0,%r0,cy-limb ldws res_ptr ldws res_ptr ldws res_ptr ldws res_ptr add stws res_ptr addc stws res_ptr addc stws res_ptr addc stws res_ptr addib 3. For the PA8000 we have to stick to using 32-bit limbs before compiler support emerges. But we want to use 64-bit operations whenever possible, in particular for loads and stores. It is possible to handle mpn_add_n efficiently by rotating (when s1/s2 are aligned), masking+bit field inserting when (they are not). The speed should double compared to the code used today. LABEL SYNTAX The HP-UX assembler takes labels starting in column 0 with no colon, L$loop ldws,mb -4(0,%r25),%r22 Gas on hppa GNU/Linux however requires a colon, L$loop: ldws,mb -4(0,%r25),%r22 This is covered by using LDEF() from asm-defs.m4. An alternative would be to use ".label" which is accepted by both, .label L$loop ldws,mb -4(0,%r25),%r22 but that's not as nice to look at, not if you're used to assembler code having labels in column 0. REFERENCES Hewlett Packard, "HP Assembler Reference Manual", 9th edition, June 1998, part number 92432-90012. ---------------- Local variables: mode: text fill-column: 76 End: