| /* Copyright (c) 2005, 2006, 2007 Helmut Wallner |
| |
| based on libc/string/strnlen.S which is |
| Copyright (c) 2002, Marek Michalkiewicz |
| |
| 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: strnlen_P.S 2191 2010-11-05 13:45:57Z arcanum $ */ |
| |
| /** \file */ |
| /** \ingroup avr_pgmspace |
| \fn size_t strnlen_P(PGM_P src, size_t len) |
| \brief Determine the length of a fixed-size string. |
| |
| The strnlen_P() function is similar to strnlen(), except that \c src is a |
| pointer to a string in program space. |
| |
| \returns The strnlen_P function returns strlen_P(src), if that is less than |
| \c len, or \c len if there is no '\\0' character among the first \c len |
| characters pointed to by \c src. */ |
| |
| |
| #if !defined(__AVR_TINY__) |
| |
| #if !defined(__DOXYGEN__) |
| |
| #include "macros.inc" |
| |
| #define src_hi r25 |
| #define src_lo r24 |
| #define len_hi r23 |
| #define len_lo r22 |
| |
| ASSEMBLY_CLIB_SECTION |
| .global _U(strnlen_P) |
| .type _U(strnlen_P), @function |
| _U(strnlen_P): |
| X_movw ZL, src_lo |
| .L_strnlen_P_loop: |
| X_lpm r0, Z+ |
| subi len_lo, lo8(1) |
| sbci len_hi, hi8(1) |
| cpse r0, __zero_reg__ |
| brcc .L_strnlen_P_loop |
| ; Z points one character past the terminating NUL |
| ; return Z - 1 - src = (-1 - src) + Z = ~src + Z |
| com src_lo |
| com src_hi |
| add src_lo, ZL |
| adc src_hi, ZH |
| ret |
| .L_strnlen_P_end: |
| .size _U(strnlen_P), .L_strnlen_P_end - _U(strnlen_P) |
| |
| #endif /* not __DOXYGEN__ */ |
| |
| #endif /* !defined(__AVR_TINY__) */ |