/* Optimized strlen for Xtensa. Copyright (C) 2001, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ #include "../../sysdeps/linux/xtensa/sysdep.h" #include <bits/xtensa-config.h> #ifdef __XTENSA_EB__ #define MASK0 0xff000000 #define MASK1 0x00ff0000 #define MASK2 0x0000ff00 #define MASK3 0x000000ff #else #define MASK0 0x000000ff #define MASK1 0x0000ff00 #define MASK2 0x00ff0000 #define MASK3 0xff000000 #endif .text ENTRY (strlen) /* a2 = s */ addi a3, a2, -4 /* because we overincrement at the end */ movi a4, MASK0 movi a5, MASK1 movi a6, MASK2 movi a7, MASK3 bbsi.l a2, 0, .L1mod2 bbsi.l a2, 1, .L2mod4 j .Laligned .L1mod2: /* address is odd */ l8ui a8, a3, 4 /* get byte 0 */ addi a3, a3, 1 /* advance string pointer */ beqz a8, .Lz3 /* if byte 0 is zero */ bbci.l a3, 1, .Laligned /* if string pointer is now word-aligned */ .L2mod4: /* address is 2 mod 4 */ addi a3, a3, 2 /* advance ptr for aligned access */ l32i a8, a3, 0 /* get word with first two bytes of string */ bnone a8, a6, .Lz2 /* if byte 2 (of word, not string) is zero */ bany a8, a7, .Laligned /* if byte 3 (of word, not string) is nonzero */ /* Byte 3 is zero. */ addi a3, a3, 3 /* point to zero byte */ sub a2, a3, a2 /* subtract to get length */ retw /* String is word-aligned. */ .align 4 /* (2 mod 4) alignment for loop instruction */ .Laligned: #if XCHAL_HAVE_LOOPS _movi.n a8, 0 /* set up for the maximum loop count */ loop a8, .Lz3 /* loop forever (almost anyway) */ #endif 1: l32i a8, a3, 4 /* get next word of string */ addi a3, a3, 4 /* advance string pointer */ bnone a8, a4, .Lz0 /* if byte 0 is zero */ bnone a8, a5, .Lz1 /* if byte 1 is zero */ bnone a8, a6, .Lz2 /* if byte 2 is zero */ #if XCHAL_HAVE_LOOPS bnone a8, a7, .Lz3 /* if byte 3 is zero */ #else bany a8, a7, 1b /* repeat if byte 3 is non-zero */ #endif .Lz3: /* Byte 3 is zero. */ addi a3, a3, 3 /* point to zero byte */ /* Fall through.... */ .Lz0: /* Byte 0 is zero. */ sub a2, a3, a2 /* subtract to get length */ retw .Lz1: /* Byte 1 is zero. */ addi a3, a3, 1 /* point to zero byte */ sub a2, a3, a2 /* subtract to get length */ retw .Lz2: /* Byte 2 is zero. */ addi a3, a3, 2 /* point to zero byte */ sub a2, a3, a2 /* subtract to get length */ retw libc_hidden_def (strlen)