source/libs/gmp/gmp-src/mpn/powerpc32/750/lshift.asm

   1 dnl  PowerPC 750 mpn_lshift -- mpn left shift.
   2
   3 dnl  Copyright 2002, 2003 Free Software Foundation, Inc.
   4
   5 dnl  This file is part of the GNU MP Library.
   6 dnl
   7 dnl  The GNU MP Library is free software; you can redistribute it and/or modify
   8 dnl  it under the terms of either:
   9 dnl
  10 dnl    * the GNU Lesser General Public License as published by the Free
  11 dnl      Software Foundation; either version 3 of the License, or (at your
  12 dnl      option) any later version.
  13 dnl
  14 dnl  or
  15 dnl
  16 dnl    * the GNU General Public License as published by the Free Software
  17 dnl      Foundation; either version 2 of the License, or (at your option) any
  18 dnl      later version.
  19 dnl
  20 dnl  or both in parallel, as here.
  21 dnl
  22 dnl  The GNU MP Library is distributed in the hope that it will be useful, but
  23 dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  24 dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  25 dnl  for more details.
  26 dnl
  27 dnl  You should have received copies of the GNU General Public License and the
  28 dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
  29 dnl  see https://www.gnu.org/licenses/.
  30
  31 include(`../config.m4')
  32
  33
  34 C       cycles/limb
  35 C 750:     3.0
  36 C 7400:    3.0
  37
  38
  39 C mp_limb_t mpn_lshift (mp_ptr dst, mp_srcptr src, mp_size_t size,
  40 C                       unsigned shift);
  41 C
  42 C This code is the same per-limb speed as mpn/powerpc32/lshift.asm, but
  43 C smaller and saving about 30 or so cycles of overhead.
  44
  45 ASM_START()
  46 PROLOGUE(mpn_lshift)
  47
  48         C r3    dst
  49         C r4    src
  50         C r5    size
  51         C r6    shift
  52
  53         mtctr   r5              C size
  54         slwi    r5, r5, 2       C 4*size
  55
  56         subfic  r7, r6, 32      C 32-shift
  57         add     r4, r4, r5      C &src[size]
  58
  59         add     r5, r3, r5      C &dst[size]
  60         lwz     r8, -4(r4)      C src[size-1]
  61         bdz     L(one)
  62
  63         lwzu    r9, -8(r4)      C src[size-2]
  64
  65         srw     r3, r8, r7      C return value
  66         slw     r8, r8, r6      C src[size-1] << shift
  67         bdz     L(two)
  68
  69
  70 L(top):
  71         C r3    return value
  72         C r4    src, incrementing
  73         C r5    dst, incrementing
  74         C r6    lshift
  75         C r7    32-shift
  76         C r8    src[i+1] << shift
  77         C r9    src[i]
  78         C r10
  79
  80         lwzu    r10, -4(r4)
  81         srw     r11, r9, r7
  82
  83         or      r8, r8, r11
  84         stwu    r8, -4(r5)
  85
  86         slw     r8, r9, r6
  87         bdz     L(odd)
  88
  89         C r8    src[i+1] << shift
  90         C r9
  91         C r10   src[i]
  92
  93         lwzu    r9, -4(r4)
  94         srw     r11, r10, r7
  95
  96         or      r8, r8, r11
  97         stwu    r8, -4(r5)
  98
  99         slw     r8, r10, r6
 100         bdnz    L(top)
 101
 102
 103 L(two):
 104         C r3    return value
 105         C r4
 106         C r5    &dst[2]
 107         C r6    shift
 108         C r7    32-shift
 109         C r8    src[1] << shift
 110         C r9    src[0]
 111         C r10
 112
 113         srw     r11, r9, r7
 114         slw     r12, r9, r6     C src[0] << shift
 115
 116         or      r8, r8, r11
 117         stw     r12, -8(r5)     C dst[0]
 118
 119         stw     r8, -4(r5)      C dst[1]
 120         blr
 121
 122
 123 L(odd):
 124         C r3    return value
 125         C r4
 126         C r5    &dst[2]
 127         C r6    shift
 128         C r7    32-shift
 129         C r8    src[1] << shift
 130         C r9
 131         C r10   src[0]
 132
 133         srw     r11, r10, r7
 134         slw     r12, r10, r6
 135
 136         or      r8, r8, r11
 137         stw     r12, -8(r5)     C dst[0]
 138
 139         stw     r8, -4(r5)      C dst[1]
 140         blr
 141
 142
 143 L(one):
 144         C r5    &dst[1]
 145         C r6    shift
 146         C r7    32-shift
 147         C r8    src[0]
 148
 149         srw     r3, r8, r7      C return value
 150         slw     r8, r8, r6      C src[size-1] << shift
 151
 152         stw     r8, -4(r5)      C dst[0]
 153         blr
 154
 155 EPILOGUE(mpn_lshift)