| dnl IBM POWER mpn_rshift -- Shift a number right. |
| |
| dnl Copyright 1992, 1994, 1999, 2000, 2001 Free Software 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 s_ptr r4 |
| dnl size r5 |
| dnl cnt r6 |
| |
| include(`../config.m4') |
| |
| ASM_START() |
| PROLOGUE(mpn_rshift) |
| sfi 8,6,32 |
| mtctr 5 C put limb count in CTR loop register |
| l 0,0(4) C read least significant limb |
| ai 9,3,-4 C adjust res_ptr since it's offset in the stu:s |
| sle 3,0,8 C compute carry limb, and init MQ register |
| bdz Lend2 C if just one limb, skip loop |
| lu 0,4(4) C read 2:nd least significant limb |
| sleq 7,0,8 C compute least significant limb of result |
| bdz Lend C if just two limb, skip loop |
| Loop: lu 0,4(4) C load next higher limb |
| stu 7,4(9) C store previous result during read latency |
| sleq 7,0,8 C compute result limb |
| bdn Loop C loop back until CTR is zero |
| Lend: stu 7,4(9) C store 2:nd most significant limb |
| Lend2: sre 7,0,6 C compute most significant limb |
| st 7,4(9) C store it |
| br |
| EPILOGUE(mpn_rshift) |
