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/* $OpenBSD: strlcpy.S,v 1.7 2005/08/07 16:40:14 espie Exp $ */
/*
* Copyright (c) 1999 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "DEFS.h"
/*
* It is faster to implement strlcpy() as two distinct operations,
* a strlen() and a memcpy(). Note that we *always* add a NUL, unless
* the count is 0.
*
* TODO: try unrolling the two main loops a bit
*/
ENTRY(strlcpy)
movl sp@(8),a0 | a0 = src
movl a0,a1 | working copy of src ptr
movl a0,d0 | return (d0) value is len(src)
notl d0 | take the complement of d0
strlcpy_len:
tstb a1@+ | did we hit the terminating NUL?
bne strlcpy_len | nope, keep going
addl a1,d0
| now set things up to do the copy
movl sp@(4),a1 | a1 = dst
movl sp@(12),d1 | d1 = count
beq strlcpy_done | zero count, just return
subql #1,d1 | subtract one for the NUL
cmpl d0, d1 | must set d1 to MIN(d0, d1)
ble strlcpy_check | count - 1 <= len(src), so d1 is ok
movl d0, d1 | d1 is too big, set it to len(src)
strlcpy_check:
tstl d1 | is d1 zero?
beq strlcpy_clear | if so, skip copy and set byte to NUL
strlcpy_copy:
movb a0@+,a1@+ | copy a byte
subql #1,d1 | decrement count
bne strlcpy_copy | space left? continue copying...
strlcpy_clear:
clrb a1@ | clear last byte
strlcpy_done:
rts
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