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      1 Copyright 2002, 2005 Free Software Foundation, Inc.
      2 
      3 This file is part of the GNU MP Library.
      4 
      5 The GNU MP Library is free software; you can redistribute it and/or modify
      6 it 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 
     12 or
     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 
     18 or both in parallel, as here.
     19 
     20 The GNU MP Library is distributed in the hope that it will be useful, but
     21 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     22 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     23 for more details.
     24 
     25 You should have received copies of the GNU General Public License and the
     26 GNU Lesser General Public License along with the GNU MP Library.  If not,
     27 see https://www.gnu.org/licenses/.
     28 
     29 
     30 
     31 
     32 
     33 This directory contains assembly code for nails-enabled 21264.  The code is not
     34 very well optimized.
     35 
     36 For addmul_N, as N grows larger, we could make multiple loads together, then do
     37 about 3.3 i/c.  10 cycles after the last load, we can increase to 4 i/c.  This
     38 would surely allow addmul_4 to run at 2 c/l, but the same should be possible
     39 also for addmul_3 and perhaps even addmul_2.
     40 
     41 
     42 		current		fair		best
     43 Routine		c/l  unroll	c/l  unroll	c/l  i/c
     44 mul_1		3.25		2.75		2.75 3.273
     45 addmul_1	4.0	4	3.5	4 14	3.25 3.385
     46 addmul_2	4.0	1	2.5	2 10	2.25 3.333
     47 addmul_3	3.0	1	2.33	2 14	2    3.333
     48 addmul_4	2.5	1	2.125	2 17	2    3.135
     49 
     50 addmul_5			2	1 10
     51 addmul_6			2	1 12
     52 addmul_7			2	1 14
     53 
     54 (The "best" column doesn't account for bookkeeping instructions and
     55 thereby assumes infinite unrolling.)
     56 
     57 Basecase usages:
     58 
     59 1	 addmul_1
     60 2	 addmul_2
     61 3	 addmul_3
     62 4	 addmul_4
     63 5	 addmul_3 + addmul_2	2.3998
     64 6	 addmul_4 + addmul_2
     65 7	 addmul_4 + addmul_3
     66