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/* Copyright (c) 2002, 2007 Reiner Patommel
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: atoi.S,v 1.14.2.1 2009/04/01 23:12:09 arcanum Exp $ */
/*
Contributors:
Created by Reiner Patommel
Changes: Jochen Pernsteiner, Marek Michalkiewicz
Changes: Reiner Patommel, 8 Feb 2003
Changes: Reiner Patommel, 13 May 2003 (DOXYGEN)
TODO: this implementation uses an inline isspace(). If Avr-libc will
use locales other than C/POSIX it is needed to call an external isspace().
ATTENTION: an external __mulhi_const_10() function is used: nonstandart
call conventions: some registers and bit T must be nochanged.
*/
/** \file */
/** \ingroup avr_stdlib
\fn int atoi(const char *s)
\brief Convert a string to an integer.
The atoi() function converts the initial portion of the string
pointed to by \p s to integer representation. In contrast to
\code (int)strtol(s, (char **)NULL, 10); \endcode
this function does not detect overflow (\c errno is not changed and
the result value is not predictable), uses smaller memory (flash and
stack) and works more quickly.
*/
#if !defined(__DOXYGEN__)
#include "macros.inc"
#define str_hi r25
#define str_lo r24
#define num_hi r25
#define num_lo r24
#define tmp r18
ASSEMBLY_CLIB_SECTION
.global _U(atoi)
.type _U(atoi), @function
/*
Skip leading spaces and tabs. Process optional sign. Stop conversion
on detection of a non-numeric character. Return 0 if string contains
no numeric characters. No check is performed whether the value is within
the range of an 'int' i.e. 32768 becomes -32768.
*/
/* This fact is used below. */
.if ('\t'-9) | ('\n'-10) | ('\f'-12) | ('\r'-13) ; '\v' is 11
.err
.endif
_U(atoi):
X_movw ZL, str_lo ; set pointer to string
CLR num_lo
CLR num_hi ; clear number
CLT ; clear sign flag
.L_atoi_loop:
LD tmp, Z+ ; get (next) character
CPI tmp, ' ' ; skip whitespace
BREQ .L_atoi_loop
CPI tmp, '\t' ; ASCII sequence is: \t,\n,\v,\f,\r
BRLO 1f
CPI tmp, '\r'+1
BRLO .L_atoi_loop
1:
CPI tmp, '+' ; if '+' convert
BREQ .L_atoi_loop2
CPI tmp, '-' ; if '-' remember sign
BRNE .L_atoi_digit
SET ; remember number is negative
RJMP .L_atoi_loop2
2: XCALL __mulhi_const_10 ; r25:r24 *= 10
ADD num_lo, tmp ; num = (num * 10) + (tmp - '0')
ADC num_hi, __zero_reg__
.L_atoi_loop2:
LD tmp, Z+
.L_atoi_digit:
SUBI tmp, '0'
CPI tmp, 10
BRLO 2b
BRTC .L_atoi_done ; positive number? -> return
COM num_hi
NEG num_lo
SBCI num_hi, -1 ; make number negative
.L_atoi_done:
RET
.L_atoi_end:
.size _U(atoi), .L_atoi_end - _U(atoi)
#endif /* not __DOXYGEN__ */
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