sysdeps/rs6000/addmul_1.s

   1 # IBM POWER __mpn_addmul_1 -- Multiply a limb vector with a limb and add
   2 # the result to a second limb vector.
   3
   4 # Copyright (C) 1992, 1994 Free Software Foundation, Inc.
   5
   6 # This file is part of the GNU MP Library.
   7
   8 # The GNU MP Library is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU Lesser General Public License as published by
  10 # the Free Software Foundation; either version 2.1 of the License, or (at your
  11 # option) any later version.
  12
  13 # The GNU MP Library is distributed in the hope that it will be useful, but
  14 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15 # or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16 # License for more details.
  17
  18 # You should have received a copy of the GNU Lesser General Public License
  19 # along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
  20 # the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  21 # MA 02111-1307, USA.
  22
  23
  24 # INPUT PARAMETERS
  25 # res_ptr       r3
  26 # s1_ptr        r4
  27 # size          r5
  28 # s2_limb       r6
  29
  30 # The RS/6000 has no unsigned 32x32->64 bit multiplication instruction.  To
  31 # obtain that operation, we have to use the 32x32->64 signed multiplication
  32 # instruction, and add the appropriate compensation to the high limb of the
  33 # result.  We add the multiplicand if the multiplier has its most significant
  34 # bit set, and we add the multiplier if the multiplicand has its most
  35 # significant bit set.  We need to preserve the carry flag between each
  36 # iteration, so we have to compute the compensation carefully (the natural,
  37 # srai+and doesn't work).  Since the POWER architecture has a branch unit
  38 # we can branch in zero cycles, so that's how we perform the additions.
  39
  40         .toc
  41         .csect .__mpn_addmul_1[PR]
  42         .align 2
  43         .globl __mpn_addmul_1
  44         .globl .__mpn_addmul_1
  45         .csect __mpn_addmul_1[DS]
  46 __mpn_addmul_1:
  47         .long .__mpn_addmul_1[PR], TOC[tc0], 0
  48         .csect .__mpn_addmul_1[PR]
  49 .__mpn_addmul_1:
  50
  51         cal     3,-4(3)
  52         l       0,0(4)
  53         cmpi    0,6,0
  54         mtctr   5
  55         mul     9,0,6
  56         srai    7,0,31
  57         and     7,7,6
  58         mfmq    8
  59         cax     9,9,7
  60         l       7,4(3)
  61         a       8,8,7           # add res_limb
  62         blt     Lneg
  63 Lpos:   bdz     Lend
  64
  65 Lploop: lu      0,4(4)
  66         stu     8,4(3)
  67         cmpi    0,0,0
  68         mul     10,0,6
  69         mfmq    0
  70         ae      8,0,9           # low limb + old_cy_limb + old cy
  71         l       7,4(3)
  72         aze     10,10           # propagate cy to new cy_limb
  73         a       8,8,7           # add res_limb
  74         bge     Lp0
  75         cax     10,10,6         # adjust high limb for negative limb from s1
  76 Lp0:    bdz     Lend0
  77         lu      0,4(4)
  78         stu     8,4(3)
  79         cmpi    0,0,0
  80         mul     9,0,6
  81         mfmq    0
  82         ae      8,0,10
  83         l       7,4(3)
  84         aze     9,9
  85         a       8,8,7
  86         bge     Lp1
  87         cax     9,9,6           # adjust high limb for negative limb from s1
  88 Lp1:    bdn     Lploop
  89
  90         b       Lend
  91
  92 Lneg:   cax     9,9,0
  93         bdz     Lend
  94 Lnloop: lu      0,4(4)
  95         stu     8,4(3)
  96         cmpi    0,0,0
  97         mul     10,0,6
  98         mfmq    7
  99         ae      8,7,9
 100         l       7,4(3)
 101         ae      10,10,0         # propagate cy to new cy_limb
 102         a       8,8,7           # add res_limb
 103         bge     Ln0
 104         cax     10,10,6         # adjust high limb for negative limb from s1
 105 Ln0:    bdz     Lend0
 106         lu      0,4(4)
 107         stu     8,4(3)
 108         cmpi    0,0,0
 109         mul     9,0,6
 110         mfmq    7
 111         ae      8,7,10
 112         l       7,4(3)
 113         ae      9,9,0           # propagate cy to new cy_limb
 114         a       8,8,7           # add res_limb
 115         bge     Ln1
 116         cax     9,9,6           # adjust high limb for negative limb from s1
 117 Ln1:    bdn     Lnloop
 118         b       Lend
 119
 120 Lend0:  cal     9,0(10)
 121 Lend:   st      8,4(3)
 122         aze     3,9
 123         br