sysdeps/powerpc/mul_1.S

   1 /* Multiply a limb vector by a limb, for PowerPC.
   2    Copyright (C) 1993-1995, 1997, 1999, 2000 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <sysdep.h>
  21 #include <bp-sym.h>
  22 #include <bp-asm.h>
  23
  24 /* mp_limb_t mpn_mul_1 (mp_ptr res_ptr, mp_srcptr s1_ptr,
  25                         mp_size_t s1_size, mp_limb_t s2_limb)
  26    Calculate s1*s2 and put result in res_ptr; return carry.  */
  27
  28 ENTRY (BP_SYM (__mpn_mul_1))
  29 #if __BOUNDED_POINTERS__
  30         slwi r10,r5,2           /* convert limbs to bytes */
  31         CHECK_BOUNDS_BOTH_WIDE (r3, r8, r9, r10)
  32         CHECK_BOUNDS_BOTH_WIDE (r4, r8, r9, r10)
  33 #endif
  34         mtctr   r5
  35
  36         lwz     r0,0(r4)
  37         mullw   r7,r0,r6
  38         mulhwu  r10,r0,r6
  39         addi    r3,r3,-4                # adjust res_ptr
  40         addic   r5,r5,0                 # clear cy with dummy insn
  41         bdz     L(1)
  42
  43 L(0):   lwzu    r0,4(r4)
  44         stwu    r7,4(r3)
  45         mullw   r8,r0,r6
  46         adde    r7,r8,r10
  47         mulhwu  r10,r0,r6
  48         bdnz    L(0)
  49
  50 L(1):   stw     r7,4(r3)
  51         addze   r3,r10
  52         blr
  53 END (BP_SYM (__mpn_mul_1))