1 Copyright 1996, 1999, 2001, 2002, 2004 Free Software Foundation, Inc.
3 This file is part of the GNU MP Library.
5 The GNU MP Library is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or (at your
8 option) any later version.
10 The GNU MP Library is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
13 License for more details.
15 You should have received a copy of the GNU Lesser General Public License
16 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
23 This directory contains mpn functions for various HP PA-RISC chips. Code
24 that runs faster on the PA7100 and later implementations, is in the pa7100
27 RELEVANT OPTIMIZATION ISSUES
31 On the PA7000 no memory instructions can issue the two cycles after a store.
32 For the PA7100, this is reduced to one cycle.
34 The PA7100 has a lookup-free cache, so it helps to schedule loads and the
35 dependent instruction really far from each other.
39 1. mpn_mul_1 could be improved to 6.5 cycles/limb on the PA7100, using the
40 instructions below (but some sw pipelining is needed to avoid the
62 2. mpn_addmul_1 could be improved from the current 10 to 7.5 cycles/limb
63 (asymptotically) on the PA7100, using the instructions below. With proper
64 sw pipelining and the unrolling level below, the speed becomes 8
108 3. For the PA8000 we have to stick to using 32-bit limbs before compiler
109 support emerges. But we want to use 64-bit operations whenever possible,
110 in particular for loads and stores. It is possible to handle mpn_add_n
111 efficiently by rotating (when s1/s2 are aligned), masking+bit field
112 inserting when (they are not). The speed should double compared to the
120 The HP-UX assembler takes labels starting in column 0 with no colon,
122 L$loop ldws,mb -4(0,%r25),%r22
124 Gas on hppa GNU/Linux however requires a colon,
126 L$loop: ldws,mb -4(0,%r25),%r22
128 This is covered by using LDEF() from asm-defs.m4. An alternative would be
129 to use ".label" which is accepted by both,
132 ldws,mb -4(0,%r25),%r22
134 but that's not as nice to look at, not if you're used to assembler code
135 having labels in column 0.
142 Hewlett Packard, "HP Assembler Reference Manual", 9th edition, June 1998,
143 part number 92432-90012.