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/* Copyright (c) 2002, 2007 Marek Michalkiewicz
Copyright (c) 2007 Dmitry Xmelkov
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of the copyright holders nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
/* $Id: memchr_P.S,v 1.1 2007/03/01 12:59:38 dmix Exp $ */
/** \file */
/** \ingroup avr_pgmspace
\fn PGM_VOID_P memchr_P(PGM_VOID_P s, int val, size_t len)
\brief Scan flash memory for a character.
The memchr_P() function scans the first \p len bytes of the flash
memory area pointed to by \p s for the character \p val. The first
byte to match \p val (interpreted as an unsigned character) stops
the operation.
\return The memchr_P() function returns a pointer to the matching
byte or \c NULL if the character does not occur in the given memory
area. */
#if !defined(__DOXYGEN__)
#include "macros.inc"
#define src_hi r25
#define src_lo r24
#define val r22
#define len_hi r21
#define len_lo r20
#define ret_hi r25
#define ret_lo r24
.text
.global _U(memchr_P)
.type _U(memchr_P), @function
_U(memchr_P):
X_movw ZL, src_lo
#if __AVR_HAVE_LPMX__
1: subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brlo 2f
lpm r0, Z+
cp r0, val
brne 1b
; OK, val is founded
sbiw ZL, 1
X_movw ret_lo, ZL
ret
; fault, val is't founded
2: clr ret_lo
clr ret_hi
ret
#else
rjmp 2f
1: lpm
cp r0, val
breq 3f
adiw ZL, 1
2: subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brsh 1b
clr ZL
clr ZH
3: X_movw ret_lo, ZL ; practicaly, this will be 2 movs
ret
#endif
.size _U(memchr_P), . - _U(memchr_P)
#endif /* not __DOXYGEN__ */
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