/* * File: arch/blackfin/lib/memcmp.S * Based on: * Author: * * Created: * Description: * * Modified: * Copyright 2004-2006 Analog Devices Inc. * * Bugs: Enter bugs at http://blackfin.uclinux.org/ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see the file COPYING, or write * to the Free Software Foundation, Inc., * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include <linux/linkage.h> /* int memcmp(const void *s1, const void *s2, size_t n); * R0 = First Address (s1) * R1 = Second Address (s2) * R2 = count (n) * * Favours word aligned data. */ .text .align 2 ENTRY(_memcmp) I1 = P3; P0 = R0; /* P0 = s1 address */ P3 = R1; /* P3 = s2 Address */ P2 = R2 ; /* P2 = count */ CC = R2 <= 7(IU); IF CC JUMP .Ltoo_small; I0 = R1; /* s2 */ R1 = R1 | R0; /* OR addresses together */ R1 <<= 30; /* check bottom two bits */ CC = AZ; /* AZ set if zero. */ IF !CC JUMP .Lbytes ; /* Jump if addrs not aligned. */ P1 = P2 >> 2; /* count = n/4 */ R3 = 3; R2 = R2 & R3; /* remainder */ P2 = R2; /* set remainder */ LSETUP (.Lquad_loop_s, .Lquad_loop_e) LC0=P1; .Lquad_loop_s: #if ANOMALY_05000202 R0 = [P0++]; R1 = [I0++]; #else MNOP || R0 = [P0++] || R1 = [I0++]; #endif CC = R0 == R1; IF !CC JUMP .Lquad_different; .Lquad_loop_e: NOP; P3 = I0; /* s2 */ .Ltoo_small: CC = P2 == 0; /* Check zero count*/ IF CC JUMP .Lfinished; /* very unlikely*/ .Lbytes: LSETUP (.Lbyte_loop_s, .Lbyte_loop_e) LC0=P2; .Lbyte_loop_s: R1 = B[P3++](Z); /* *s2 */ R0 = B[P0++](Z); /* *s1 */ CC = R0 == R1; IF !CC JUMP .Ldifferent; .Lbyte_loop_e: NOP; .Ldifferent: R0 = R0 - R1; P3 = I1; RTS; .Lquad_different: /* We've read two quads which don't match. * Can't just compare them, because we're * a little-endian machine, so the MSBs of * the regs occur at later addresses in the * string. * Arrange to re-read those two quads again, * byte-by-byte. */ P0 += -4; /* back up to the start of the */ P3 = I0; /* quads, and increase the*/ P2 += 4; /* remainder count*/ P3 += -4; JUMP .Lbytes; .Lfinished: R0 = 0; P3 = I1; RTS; ENDPROC(_memcmp)