4.223.1 strlcpy.S

/*
   AVR LIBC
   strlcpy()

   Copyright (c) 2003, 2007 Eric B. Weddington, R. Patommel
   Copyright (c) 2009  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.

*/

/* $Id$ */

#if !defined(__AVR_TINY__)

#if !defined(__DOXYGEN__)

#include "asmdef.h"

#define dst_lo      r24
#define src_hi      r23
#define src_lo      r22
#define siz_hi      r21
#define siz_lo      r20
#define rslt_lo     r24


ENTRY strlcpy
    X_movw  XL, dst_lo      ; X = dst
    X_movw  ZL, src_lo      ; Z = src

  ; copy loop
1:  subi    siz_lo, lo8(1)
    sbci    siz_hi, hi8(1)
    brcs    4f          ; is possible with siz == 0
    breq    3f          ; --> siz chars copied
    ld  __tmp_reg__, Z+
    st  X+, __tmp_reg__
    tst __tmp_reg__
    brne    1b

  ; calculate result (Z - 1 - src) and return
2:  sub ZL, src_lo
    sbc ZH, src_hi
    sbiw    ZL, 1
    X_movw  rslt_lo, ZL
    ret

  ; terminate dst
3:  st  X, __zero_reg__

  ; find src end
4:  ld  __tmp_reg__, Z+
    tst __tmp_reg__
    brne    4b
    rjmp    2b

ENDFUNC

#endif /* not __DOXYGEN__ */

#endif /* !defined(__AVR_TINY__) */