1/* IBM POWER rshift 2 * 3 * Copyright (C) 1992, 1994, 1999, 2002 Free Software Foundation, Inc. 4 * 5 * This file is part of Libgcrypt. 6 * 7 * Libgcrypt is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU Lesser General Public License as 9 * published by the Free Software Foundation; either version 2.1 of 10 * the License, or (at your option) any later version. 11 * 12 * Libgcrypt is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 20 */ 21 22#include "sysdep.h" 23#include "asm-syntax.h" 24 25 26/* 27# INPUT PARAMETERS 28# res_ptr r3 29# s_ptr r4 30# size r5 31# cnt r6 32*/ 33 34 .toc 35 .extern _gcry_mpih_rshift[DS] 36 .extern ._gcry_mpih_rshift 37.csect [PR] 38 .align 2 39 .globl _gcry_mpih_rshift 40 .globl ._gcry_mpih_rshift 41 .csect _gcry_mpih_rshift[DS] 42_gcry_mpih_rshift: 43 .long ._gcry_mpih_rshift, TOC[tc0], 0 44 .csect [PR] 45._gcry_mpih_rshift: 46 sfi 8,6,32 47 mtctr 5 # put limb count in CTR loop register 48 l 0,0(4) # read least significant limb 49 ai 9,3,-4 # adjust res_ptr since it's offset in the stu:s 50 sle 3,0,8 # compute carry limb, and init MQ register 51 bdz Lend2 # if just one limb, skip loop 52 lu 0,4(4) # read 2:nd least significant limb 53 sleq 7,0,8 # compute least significant limb of result 54 bdz Lend # if just two limb, skip loop 55Loop: lu 0,4(4) # load next higher limb 56 stu 7,4(9) # store previous result during read latency 57 sleq 7,0,8 # compute result limb 58 bdn Loop # loop back until CTR is zero 59Lend: stu 7,4(9) # store 2:nd most significant limb 60Lend2: sre 7,0,6 # compute most significant limb 61 st 7,4(9) # store it 62 br 63 64 65