1dnl IBM POWER mpn_rshift -- Shift a number right. 2 3dnl Copyright 1992, 1994, 1999-2001 Free Software Foundation, Inc. 4 5dnl This file is part of the GNU MP Library. 6dnl 7dnl The GNU MP Library is free software; you can redistribute it and/or modify 8dnl it under the terms of either: 9dnl 10dnl * the GNU Lesser General Public License as published by the Free 11dnl Software Foundation; either version 3 of the License, or (at your 12dnl option) any later version. 13dnl 14dnl or 15dnl 16dnl * the GNU General Public License as published by the Free Software 17dnl Foundation; either version 2 of the License, or (at your option) any 18dnl later version. 19dnl 20dnl or both in parallel, as here. 21dnl 22dnl The GNU MP Library is distributed in the hope that it will be useful, but 23dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 24dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 25dnl for more details. 26dnl 27dnl You should have received copies of the GNU General Public License and the 28dnl GNU Lesser General Public License along with the GNU MP Library. If not, 29dnl see https://www.gnu.org/licenses/. 30 31 32dnl INPUT PARAMETERS 33dnl res_ptr r3 34dnl s_ptr r4 35dnl size r5 36dnl cnt r6 37 38include(`../config.m4') 39 40ASM_START() 41PROLOGUE(mpn_rshift) 42 sfi 8,6,32 43 mtctr 5 C put limb count in CTR loop register 44 l 0,0(4) C read least significant limb 45 ai 9,3,-4 C adjust res_ptr since it's offset in the stu:s 46 sle 3,0,8 C compute carry limb, and init MQ register 47 bdz Lend2 C if just one limb, skip loop 48 lu 0,4(4) C read 2:nd least significant limb 49 sleq 7,0,8 C compute least significant limb of result 50 bdz Lend C if just two limb, skip loop 51Loop: lu 0,4(4) C load next higher limb 52 stu 7,4(9) C store previous result during read latency 53 sleq 7,0,8 C compute result limb 54 bdn Loop C loop back until CTR is zero 55Lend: stu 7,4(9) C store 2:nd most significant limb 56Lend2: sre 7,0,6 C compute most significant limb 57 st 7,4(9) C store it 58 br 59EPILOGUE(mpn_rshift) 60