/* memcmp.S * Copyright (C) 2003-2007 Analog Devices Inc., All Rights Reserved. * * This file is subject to the terms and conditions of the GNU Library General * Public License. See the file "COPYING.LIB" in the main directory of this * archive for more details. * * Non-LGPL License also available as part of VisualDSP++ * http://www.analog.com/processors/resources/crosscore/visualDspDevSoftware.html */ #include <sysdep.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 .weak _memcmp 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 !defined(__WORKAROUND_AVOID_DAG1) MNOP || R0 = [P0++] || R1 = [I0++]; #else 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; .size _memcmp,.-_memcmp libc_hidden_def (memcmp) #ifdef __UCLIBC_SUSV3_LEGACY__ weak_alias (memcmp,bcmp) #endif