1*9b9d2a55Sguenther/* $OpenBSD: bcopy.S,v 1.5 2015/08/31 02:53:56 guenther Exp $ */ 20eea0d08Spefo/*- 30eea0d08Spefo * Copyright (c) 1991, 1993 40eea0d08Spefo * The Regents of the University of California. All rights reserved. 50eea0d08Spefo * 60eea0d08Spefo * This code is derived from software contributed to Berkeley by 70eea0d08Spefo * Ralph Campbell. 80eea0d08Spefo * 90eea0d08Spefo * Redistribution and use in source and binary forms, with or without 100eea0d08Spefo * modification, are permitted provided that the following conditions 110eea0d08Spefo * are met: 120eea0d08Spefo * 1. Redistributions of source code must retain the above copyright 130eea0d08Spefo * notice, this list of conditions and the following disclaimer. 140eea0d08Spefo * 2. Redistributions in binary form must reproduce the above copyright 150eea0d08Spefo * notice, this list of conditions and the following disclaimer in the 160eea0d08Spefo * documentation and/or other materials provided with the distribution. 170eea0d08Spefo * 3. Neither the name of the University nor the names of its contributors 180eea0d08Spefo * may be used to endorse or promote products derived from this software 190eea0d08Spefo * without specific prior written permission. 200eea0d08Spefo * 210eea0d08Spefo * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 220eea0d08Spefo * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 230eea0d08Spefo * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 240eea0d08Spefo * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 250eea0d08Spefo * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 260eea0d08Spefo * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 270eea0d08Spefo * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 280eea0d08Spefo * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 290eea0d08Spefo * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 300eea0d08Spefo * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 310eea0d08Spefo * SUCH DAMAGE. 320eea0d08Spefo */ 330eea0d08Spefo 34*9b9d2a55Sguenther#include "SYS.h" 350eea0d08Spefo 360eea0d08Spefo/* bcopy(s1, s2, n) */ 370eea0d08Spefo 380eea0d08Spefo 395738bc62SpefoLEAF(bcopy, 0) 400eea0d08Spefo .set noreorder 4150027fe1Smiod daddu t0, a0, a2 # t0 = end of s1 region 420eea0d08Spefo sltu t1, a1, t0 430eea0d08Spefo sltu t2, a0, a1 440eea0d08Spefo and t1, t1, t2 # t1 = true if from < to < (from+len) 450eea0d08Spefo beq t1, zero, forward # non overlapping, do forward copy 460eea0d08Spefo slt t2, a2, 12 # check for small copy 470eea0d08Spefo 480eea0d08Spefo ble a2, zero, 2f 4950027fe1Smiod daddu t1, a1, a2 # t1 = end of to region 500eea0d08Spefo1: 510eea0d08Spefo lb v0, -1(t0) # copy bytes backwards, 5250027fe1Smiod dsubu t0, t0, 1 # does not happen often so do slow way 5350027fe1Smiod dsubu t1, t1, 1 540eea0d08Spefo bne t0, a0, 1b 550eea0d08Spefo sb v0, 0(t1) 560eea0d08Spefo2: 570eea0d08Spefo j ra 580eea0d08Spefo nop 590eea0d08Spefoforward: 600eea0d08Spefo bne t2, zero, smallcpy # do a small bcopy 610eea0d08Spefo xor v0, a0, a1 # compare low two bits of addresses 620eea0d08Spefo and v0, v0, 3 6350027fe1Smiod dsubu a3, zero, a1 # compute # bytes to word align address 640eea0d08Spefo beq v0, zero, aligned # addresses can be word aligned 650eea0d08Spefo and a3, a3, 3 660eea0d08Spefo 670eea0d08Spefo beq a3, zero, 1f 6850027fe1Smiod dsubu a2, a2, a3 # subtract from remaining count 690eea0d08Spefo LWHI v0, 0(a0) # get next 4 bytes (unaligned) 700eea0d08Spefo LWLO v0, 3(a0) 7150027fe1Smiod daddu a0, a0, a3 720eea0d08Spefo SWHI v0, 0(a1) # store 1, 2, or 3 bytes to align a1 7350027fe1Smiod daddu a1, a1, a3 740eea0d08Spefo1: 750eea0d08Spefo and v0, a2, 3 # compute number of words left 7650027fe1Smiod dsubu a3, a2, v0 770eea0d08Spefo move a2, v0 7850027fe1Smiod daddu a3, a3, a0 # compute ending address 790eea0d08Spefo2: 800eea0d08Spefo LWHI v0, 0(a0) # copy words a0 unaligned, a1 aligned 810eea0d08Spefo LWLO v0, 3(a0) 8250027fe1Smiod daddu a0, a0, 4 8350027fe1Smiod daddu a1, a1, 4 840eea0d08Spefo bne a0, a3, 2b 850eea0d08Spefo sw v0, -4(a1) 860eea0d08Spefo b smallcpy 870eea0d08Spefo nop 880eea0d08Spefoaligned: 890eea0d08Spefo beq a3, zero, 1f 9050027fe1Smiod dsubu a2, a2, a3 # subtract from remaining count 910eea0d08Spefo LWHI v0, 0(a0) # copy 1, 2, or 3 bytes to align 9250027fe1Smiod daddu a0, a0, a3 930eea0d08Spefo SWHI v0, 0(a1) 9450027fe1Smiod daddu a1, a1, a3 950eea0d08Spefo1: 960eea0d08Spefo and v0, a2, 3 # compute number of whole words left 9750027fe1Smiod dsubu a3, a2, v0 980eea0d08Spefo move a2, v0 9950027fe1Smiod daddu a3, a3, a0 # compute ending address 1000eea0d08Spefo2: 1010eea0d08Spefo lw v0, 0(a0) # copy words 10250027fe1Smiod daddu a0, a0, 4 10350027fe1Smiod daddu a1, a1, 4 1040eea0d08Spefo bne a0, a3, 2b 1050eea0d08Spefo sw v0, -4(a1) 1060eea0d08Spefosmallcpy: 1070eea0d08Spefo ble a2, zero, 2f 10850027fe1Smiod daddu a3, a2, a0 # compute ending address 1090eea0d08Spefo1: 1100eea0d08Spefo lbu v0, 0(a0) # copy bytes 11150027fe1Smiod daddu a0, a0, 1 11250027fe1Smiod daddu a1, a1, 1 1130eea0d08Spefo bne a0, a3, 1b 1140eea0d08Spefo sb v0, -1(a1) 1150eea0d08Spefo2: 1160eea0d08Spefo j ra 1170eea0d08Spefo nop 1180eea0d08Spefo .set reorder 119*9b9d2a55SguentherEND_WEAK(bcopy) 120