| dnl IBM POWER mpn_sub_n -- Subtract two limb vectors of equal, non-zero |
| dnl length. |
| |
| dnl Copyright 1992, 1994, 1995, 1996, 1999, 2000, 2001, 2005 Free Software |
| dnl Foundation, Inc. |
| |
| dnl This file is part of the GNU MP Library. |
| |
| dnl The GNU MP Library is free software; you can redistribute it and/or modify |
| dnl it under the terms of the GNU Lesser General Public License as published |
| dnl by the Free Software Foundation; either version 3 of the License, or (at |
| dnl your option) any later version. |
| |
| dnl The GNU MP Library is distributed in the hope that it will be useful, but |
| dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| dnl License for more details. |
| |
| dnl You should have received a copy of the GNU Lesser General Public License |
| dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. |
| |
| |
| dnl INPUT PARAMETERS |
| dnl res_ptr r3 |
| dnl s1_ptr r4 |
| dnl s2_ptr r5 |
| dnl size r6 |
| |
| include(`../config.m4') |
| |
| ASM_START() |
| PROLOGUE(mpn_sub_n) |
| andil. 10,6,1 C odd or even number of limbs? |
| l 8,0(4) C load least significant s1 limb |
| l 0,0(5) C load least significant s2 limb |
| cal 3,-4(3) C offset res_ptr, it's updated before it's used |
| sri 10,6,1 C count for unrolled loop |
| sf 7,0,8 C subtract least significant limbs, set cy |
| mtctr 10 C copy count into CTR |
| beq 0,Leven C branch if even # of limbs (# of limbs >= 2) |
| |
| C We have an odd # of limbs. Add the first limbs separately. |
| cmpi 1,10,0 C is count for unrolled loop zero? |
| bc 4,6,L1 C bne cr1,L1 (misassembled by gas) |
| st 7,4(3) |
| sfe 3,0,0 C load !cy into ... |
| sfi 3,3,0 C ... return value register |
| br C return |
| |
| C We added least significant limbs. Now reload the next limbs to enter loop. |
| L1: lu 8,4(4) C load s1 limb and update s1_ptr |
| lu 0,4(5) C load s2 limb and update s2_ptr |
| stu 7,4(3) |
| sfe 7,0,8 C subtract limbs, set cy |
| Leven: lu 9,4(4) C load s1 limb and update s1_ptr |
| lu 10,4(5) C load s2 limb and update s2_ptr |
| bdz Lend C If done, skip loop |
| |
| Loop: lu 8,4(4) C load s1 limb and update s1_ptr |
| lu 0,4(5) C load s2 limb and update s2_ptr |
| sfe 11,10,9 C subtract previous limbs with cy, set cy |
| stu 7,4(3) C |
| lu 9,4(4) C load s1 limb and update s1_ptr |
| lu 10,4(5) C load s2 limb and update s2_ptr |
| sfe 7,0,8 C subtract previous limbs with cy, set cy |
| stu 11,4(3) C |
| bdn Loop C decrement CTR and loop back |
| |
| Lend: sfe 11,10,9 C subtract limbs with cy, set cy |
| st 7,4(3) C |
| st 11,8(3) C |
| sfe 3,0,0 C load !cy into ... |
| sfi 3,3,0 C ... return value register |
| br |
| EPILOGUE(mpn_sub_n) |
