4.261.1 strtok_rP.S

/* 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"

/*  char *strtok_r (char *s, const char *delim, char **last)
    {
    char *p = *last;
    const char *q;
    char c, d;

    if (!s) {
        if (!p) return s;       // end of string
        s = p;          // continue parsing
    }

    p = s;
    for (;;) {          // skip delimeters
        s = p;          // space optimization (vs. s = p-1)
        if (!(c = *p++)) {
        s = 0;
        p = 0;
        goto ret;
        }
        q = delim;
        do {
        if (!(d = *q++))
            goto find_end;
        } while (d != c);
    }

      find_end:
    do {
        q = delim;
        do {
        d = *q++;
        if (c == d) {
            *--p = 0;
            p++;
            goto ret;
        }
        } while (d);
    } while ((c = *p++) != 0);
    p = 0;              // stop parsing
      ret:
    *last = p;
    return s;
    }
 */

#define str_hi  r25
#define str_lo  r24
#define dlm_lo  r22
#define lst_lo  r20

ENTRY strtok_rP

/* Two variants below are different in registers to load chars. In case
   of enhanced core it is convinient to use <R0,R1> pair as zero word.
   In classic case it is optimal to load delimeter char (flash) to R0.
 */

/* -------------------------------------------------------------------- */
#if __AVR_HAVE_LPMX__

# define dlm_ch r18     /* delimeter character  */
# define str_ch r0      /* string character */

    X_movw  ZL, lst_lo
    ld  XL, Z+          ; X = *last
    ld  XH, Z
  ; check str
    sbiw    str_lo, 0
    brne    1f
    sbiw    XL, 0
    breq    .Lret           ; end of string
    X_movw  str_lo, XL      ; continue parsing

  ; skip delimeters
1:  X_movw  XL, str_lo      ; p = str
2:  X_movw  str_lo, XL
    ld  str_ch, X+
    tst str_ch
    brne    3f
    X_movw  str_lo, str_ch      ; <r0,r1>
    rjmp    .Lclr
3:  X_movw  ZL, dlm_lo
4:  lpm dlm_ch, Z+
    tst dlm_ch
    breq    5f          ; goto find
    cp  dlm_ch, str_ch
    brne    4b
    rjmp    2b          ; skip 1 byte

  ; find new token end
5:  X_movw  ZL, dlm_lo
6:  lpm dlm_ch, Z+
    cp  dlm_ch, str_ch      ; str_ch != 0
    brne    7f
    st  -X, __zero_reg__
    adiw    XL, 1
    rjmp    .Lret
7:  tst dlm_ch
    brne    6b
  ; next str byte
    ld  str_ch, X+
    tst str_ch
    brne    5b

  ; stop parsing
.Lclr:  X_movw  XL, str_ch      ; <r0,r1>
  ; save last pointer
.Lret:  X_movw  ZL, lst_lo      ; *last = X
    st  Z+, XL
    st  Z, XH
    ret

/* -------------------------------------------------------------------- */
#else   /* !__AVR_HAVE_LPMX__ */

# define dlm_ch r0      /* delimeter character  */
# define str_ch r18     /* string character */

    X_movw  ZL, lst_lo
    ld  XL, Z+          ; X = *last
    ld  XH, Z
  ; check str
    sbiw    str_lo, 0
    brne    1f
    sbiw    XL, 0
    breq    .Lret           ; end of string
    X_movw  str_lo, XL      ; continue parsing

  ; skip delimeters
1:  X_movw  XL, str_lo      ; p = str
2:  X_movw  str_lo, XL
    ld  str_ch, X+
    tst str_ch
    brne    3f
    clr str_lo          ; return value
    clr str_hi
    rjmp    .Lclr
3:  X_movw  ZL, dlm_lo
4:  lpm             ; lpm r0,Z
    adiw    ZL, 1
    tst dlm_ch
    breq    5f          ; goto find
    cp  dlm_ch, str_ch
    brne    4b
    rjmp    2b          ; skip 1 byte

  ; find new token end
5:  X_movw  ZL, dlm_lo
6:  lpm             ; lpm r0,Z
    adiw    ZL, 1
    cp  dlm_ch, str_ch      ; str_ch != 0
    brne    7f
    st  -X, __zero_reg__
    adiw    XL, 1
    rjmp    .Lret
7:  tst dlm_ch
    brne    6b
  ; next str byte
    ld  str_ch, X+
    tst str_ch
    brne    5b

  ; stop parsing
.Lclr:  clr XL
    clr XH
  ; save last pointer
.Lret:  X_movw  ZL, lst_lo      ; *last = X
    st  Z+, XL
    st  Z, XH
    ret

/* -------------------------------------------------------------------- */
#endif  /* !__AVR_HAVE_LPMX__ */

ENDFUNC

#endif /* not __DOXYGEN__ */

#endif /* !defined(__AVR_TINY__) */