sysdeps/powerpc/powerpc32/rshift.S

   1 /* Shift a limb right, low level routine.
   2    Copyright (C) 1995-2013 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20 #include <bp-sym.h>
  21 #include <bp-asm.h>
  22
  23 /* INPUT PARAMETERS
  24    res_ptr      r3
  25    s1_ptr       r4
  26    size         r5
  27    cnt          r6  */
  28
  29 ENTRY (BP_SYM (__mpn_rshift))
  30 #if __BOUNDED_POINTERS__
  31         slwi r10,r5,2           /* convert limbs to bytes */
  32         CHECK_BOUNDS_BOTH_WIDE (r3, r8, r9, r10)
  33         CHECK_BOUNDS_BOTH_WIDE (r4, r8, r9, r10)
  34 #endif
  35         mtctr   r5              # copy size into CTR
  36         addi    r7,r3,-4        # move adjusted res_ptr to free return reg
  37         subfic  r8,r6,32
  38         lwz     r11,0(r4)       # load first s1 limb
  39         slw     r3,r11,r8       # compute function return value
  40         bdz     L(1)
  41
  42 L(0):   lwzu    r10,4(r4)
  43         srw     r9,r11,r6
  44         slw     r12,r10,r8
  45         or      r9,r9,r12
  46         stwu    r9,4(r7)
  47         bdz     L(2)
  48         lwzu    r11,4(r4)
  49         srw     r9,r10,r6
  50         slw     r12,r11,r8
  51         or      r9,r9,r12
  52         stwu    r9,4(r7)
  53         bdnz    L(0)
  54
  55 L(1):   srw     r0,r11,r6
  56         stw     r0,4(r7)
  57         blr
  58
  59 L(2):   srw     r0,r10,r6
  60         stw     r0,4(r7)
  61         blr
  62 END (BP_SYM (__mpn_rshift))