| /* Copyright (c) 2002, 2007 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: strncpy.S 1944 2009-04-01 23:12:20Z arcanum $ */ |
| |
| /** \file */ |
| /** \ingroup avr_string |
| \fn char *strncpy(char *dest, const char *src, size_t len) |
| \brief Copy a string. |
| |
| The strncpy() function is similar to strcpy(), except that not more than n |
| bytes of src are copied. Thus, if there is no null byte among the first n |
| bytes of src, the result will not be null-terminated. |
| |
| In the case where the length of src is less than that of n, the remainder |
| of dest will be padded with nulls. |
| |
| \returns The strncpy() function returns a pointer to the destination |
| string dest. */ |
| |
| #if !defined(__DOXYGEN__) |
| |
| #include "macros.inc" |
| |
| #define dest_hi r25 |
| #define dest_lo r24 |
| #define src_hi r23 |
| #define src_lo r22 |
| #define len_hi r21 |
| #define len_lo r20 |
| |
| ASSEMBLY_CLIB_SECTION |
| .global _U(strncpy) |
| .type _U(strncpy), @function |
| _U(strncpy): |
| X_movw ZL, src_lo |
| X_movw XL, dest_lo |
| .L_strncpy_loop: |
| subi len_lo, lo8(1) |
| sbci len_hi, hi8(1) |
| brcs .L_strncpy_done |
| ld __tmp_reg__, Z+ |
| st X+, __tmp_reg__ |
| tst __tmp_reg__ |
| brne .L_strncpy_loop |
| ; store null characters up to the end of dest |
| ; as the glibc manual says: |
| ; This behavior is rarely useful, but it is specified by the ISO C standard. |
| rjmp .L_strncpy_clr_start |
| .L_strncpy_clr_loop: |
| st X+, __zero_reg__ |
| .L_strncpy_clr_start: |
| subi len_lo, lo8(1) |
| sbci len_hi, hi8(1) |
| brcc .L_strncpy_clr_loop |
| .L_strncpy_done: |
| ; return dest (unchanged) |
| ret |
| .L_strncpy_end: |
| .size _U(strncpy), .L_strncpy_end - _U(strncpy) |
| |
| #endif /* not __DOXYGEN__ */ |