1*27620987Smatt/* $NetBSD: mulsi3.S,v 1.1 2014/09/03 19:34:25 matt Exp $ */ 2*27620987Smatt 3*27620987Smatt/*- 4*27620987Smatt * Copyright (c) 2014 The NetBSD Foundation, Inc. 5*27620987Smatt * All rights reserved. 6*27620987Smatt * 7*27620987Smatt * This code is derived from software contributed to The NetBSD Foundation 8*27620987Smatt * by Matt Thomas of 3am Software Foundry. 9*27620987Smatt * 10*27620987Smatt * Redistribution and use in source and binary forms, with or without 11*27620987Smatt * modification, are permitted provided that the following conditions 12*27620987Smatt * are met: 13*27620987Smatt * 1. Redistributions of source code must retain the above copyright 14*27620987Smatt * notice, this list of conditions and the following disclaimer. 15*27620987Smatt * 2. Redistributions in binary form must reproduce the above copyright 16*27620987Smatt * notice, this list of conditions and the following disclaimer in the 17*27620987Smatt * documentation and/or other materials provided with the distribution. 18*27620987Smatt * 19*27620987Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20*27620987Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21*27620987Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22*27620987Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23*27620987Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24*27620987Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25*27620987Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26*27620987Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27*27620987Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28*27620987Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29*27620987Smatt * POSSIBILITY OF SUCH DAMAGE. 30*27620987Smatt */ 31*27620987Smatt 32*27620987Smatt#include <machine/asm.h> 33*27620987Smatt 34*27620987Smatt__RCSID("$NetBSD: mulsi3.S,v 1.1 2014/09/03 19:34:25 matt Exp $") 35*27620987Smatt 36*27620987SmattENTRY(__mulsi3) 37*27620987Smatt l.movhi r11, 0 38*27620987Smatt 39*27620987Smatt l.sfeqi r3, 0 40*27620987Smatt l.bf .Lret 41*27620987Smatt l.nop 42*27620987Smatt 43*27620987Smatt l.sfeqi r4, 0 44*27620987Smatt l.bf .Lret 45*27620987Smatt l.nop 46*27620987Smatt 47*27620987Smatt l.sfleu r3, r4 # is r3 < r4 (unsigned) 48*27620987Smatt#if 0 49*27620987Smatt l.ori r6, r3, 0 # move r3 to r6 50*27620987Smatt l.bf .Lloop # yes, r6 already has smaller value, 51*27620987Smatt l.nop 52*27620987Smatt l.ori r6, r4, 0 # move r4 to r6 because it's smaller than r3 53*27620987Smatt#else 54*27620987Smatt l.cmov r6, r3, r4 # choose lesser of r3 or r4 55*27620987Smatt#endif 56*27620987Smatt 57*27620987Smatt.Lloop: 58*27620987Smatt l.andi r5, r6, 1 # get LSB 59*27620987Smatt l.sub r8, r0, r5 # 0 -> 0, 1 -> 0xffffffff 60*27620987Smatt l.and r8, r8, r4 # r8 = r6 & 1 ? r4 : 0 61*27620987Smatt l.add r11, r11, r8 # add to result 62*27620987Smatt l.srli r4, r4, 1 # discard LSB 63*27620987Smatt l.slli r6, r6, 1 # multiply by 2 64*27620987Smatt.Lentry: 65*27620987Smatt l.sfeqi r4, 0 # only 0 left? 66*27620987Smatt l.bf .Lret # yes, we're done 67*27620987Smatt l.nop 68*27620987Smatt l.sfeqi r6, 0 # only 0 left? 69*27620987Smatt l.bnf .Lloop # no, another round of long multiplication. 70*27620987Smatt l.nop 71*27620987Smatt 72*27620987Smatt.Lret: l.jr lr 73*27620987Smatt l.nop 74*27620987SmattEND(__mulsi3) 75