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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.file "strlcpy.s"
/*
* The strlcpy() function copies at most dstsize-1 characters
* (dstsize being the size of the string buffer dst) from src
* to dst, truncating src if necessary. The result is always
* null-terminated. The function returns strlen(src). Buffer
* overflow can be checked as follows:
*
* if (strlcpy(dst, src, dstsize) >= dstsize)
* return -1;
*/
#include <sys/asm_linkage.h>
! strlcpy implementation is similar to that of strcpy, except
! in this case, the maximum size of the detination must be
! tracked since it bounds our maximum copy size. However,
! we must still continue to check for zero since the routine
! is expected to null-terminate any string that is within
! the dest size bound.
!
! this method starts by checking for and arranging source alignment.
! Once this has occurred, we copy based upon destination alignment.
! This is either by word, halfword, or byte. As this occurs, we
! check for a zero-byte. If one is found, we branch to a method
! which checks for the exact location of a zero-byte within a
! larger word/half-word quantity.
ENTRY(strlcpy)
.align 32
save %sp, -SA(WINDOWSIZE), %sp
subcc %g0, %i2, %g4 ! n = -n or n == 0 ?
bz,pn %icc, .getstrlen ! if 0 do nothing but strlen(src)
add %i1, %i2, %i3 ! i3 = src + n
andcc %i1, 3, %i4 ! word aligned?
bz,pn %icc, .wordaligned
add %i0, %i2, %i2 ! n = dst + n
sub %i4, 4, %i4 ! bytes until src aligned
.alignsrc:
ldub [%i3 + %g4], %l1 ! l1 = src[]
andcc %l1, 0xff, %g0 ! null byte reached?
stub %l1, [%i2 + %g4] ! dst[] = src[]
bz,a %icc, .done
add %i2, %g4, %i2 ! get single dest ptr for strlen
addcc %g4, 1, %g4 ! src++ dest++ n--
bz,pn %icc, .forcenullunalign ! n == 0, append null byte
addcc %i4, 1, %i4 ! incr, check align
bnz,a %icc, .alignsrc
nop
.wordaligned:
sethi %hi(0x01010101), %i4
add %i2, %g4, %l0 ! l0 = dest
or %i4, %lo(0x01010101), %i4
sub %i2, 4, %i2 ! pre-incr for in cpy loop
andcc %l0, 3, %g1 ! word aligned?
bnz %icc, .dstnotaligned
sll %i4, 7, %i5 ! Mycroft part deux
.storeword:
ld [%i3 + %g4], %l1 ! l1 = src[]
addcc %g4, 4, %g4 ! n += 4, src += 4, dst +=4
bcs,pn %icc, .lastword
andn %i5, %l1, %g1 ! ~word & 0x80808080
sub %l1, %i4, %l0 ! word - 0x01010101
andcc %l0, %g1, %g0 ! doit
bz,a,pt %icc, .storeword ! if expr == 0, no zero byte
st %l1, [%i2 + %g4] ! dst[] = src[]
.zerobyte:
add %i2, %g4, %i2 ! ptr to dest
srl %l1, 24, %g1 ! 1st byte
andcc %g1, 0xff, %g0 ! test for end
bz,pn %icc, .done
stb %g1, [%i2] ! store byte
add %i2, 1, %i2 ! dst ++
srl %l1, 16, %g1 ! 2nd byte
andcc %g1, 0xff, %g0 ! zero byte ?
bz,pn %icc, .done
stb %g1, [%i2] ! store byte
add %i2, 1, %i2 ! dst ++
srl %l1, 8, %g1 ! 3rd byte
andcc %g1, 0xff, %g0 ! zero byte ?
bz,pn %icc, .done
stb %g1, [%i2] ! store byte
stb %l1, [%i2 + 1] ! store last byte
add %i2, 1, %i2 ! dst ++
.done:
sub %i2, %i0, %i0 ! len = dst - orig dst
ret
restore %i0, %g0, %o0
.lastword:
add %i2, %g4, %i2
sub %g4, 4, %g4 ! undo pre-incr
add %i3, %g4, %i3
srl %l1, 24, %g1 ! 1st byte
andcc %g1, 0xff, %g0 ! zero byte?
bz,pn %icc, .done
stb %g1, [%i2] ! store byte
inccc %g4 ! n--
bz .forcenull
srl %l1, 16, %g1 ! 2nd byte
add %i2, 1, %i2 ! dst++
andcc %g1, 0xff, %g0 ! zero?
bz,pn %icc, .done
stb %g1, [%i2] ! store
inccc %g4
bz .forcenull
srl %l1, 8, %g1 ! 3rd byte
add %i2, 1, %i2 ! dst++
andcc %g1, 0xff, %g0 ! zero?
bz,pn %icc, .done
stb %g1, [%i2] ! store
inccc %g4 ! n--
bz .forcenull
andcc %l1, 0xff, %g0 ! zero?
add %i2, 1, %i2 ! dst++
bz,pn %ncc, .done
stb %l1, [%i2]
.forcenull:
stb %g0, [%i2]
.searchword:
ld [%i3], %l1
.searchword2:
andn %i5, %l1, %g1 ! word & 0x80808080
sub %l1, %i4, %l0 ! word - 0x01010101
andcc %l0, %g1, %g0 ! do it
bz,a,pt %icc, .searchword
add %i3, 4, %i3 ! src += 4
mov 0xff, %i5
sll %i5, 24, %i5 ! mask 1st byte = 0xff000000
.searchbyte:
andcc %l1, %i5, %g0 ! cur byte 0?
srl %i5, 8, %i5 ! mask next byte
bnz,a %icc, .searchbyte ! cur !=0 continue
add %i3, 1, %i3
.endfound:
sub %i3, %i1, %i0 ! len = src - orig src
ret
restore %i0, %g0, %o0
nop
.dstnotaligned:
cmp %g1, 2 ! halfword aligned?
be .storehalfword2
.empty
.storebyte:
ld [%i3 + %g4], %l1 ! load src word
addcc %g4, 4, %g4 ! src +=4 dst +=4
bcs,pn %icc, .lastword
andn %i5, %l1, %g1 ! ~x & 0x80808080
sub %l1, %i4, %l0 ! x - 0x01010101
andcc %l0, %g1, %g0 ! get your Mycroft on
bnz,pn %icc, .zerobyte ! non-zero, we have zero byte
add %i2, %g4, %l0 ! dst in ptr form
srl %l1, 24, %g1 ! get 1st byte, then be hw aligned
stb %g1, [%l0]
srl %l1, 8, %g1 ! 2nd & 3rd bytes
sth %g1, [%l0 + 1]
ba .storebyte
stb %l1, [%l0 + 3] ! store 4th byte
.storehalfword:
ld [%i3 + %g4], %l1 ! src word
.storehalfword2:
addcc %g4, 4, %g4 ! src += 4 dst += 4
bcs,pn %icc, .lastword
andn %i5, %l1, %g1 ! ~x & 0x80808080
sub %l1, %i4, %l0 ! x - 0x01010101
andcc %l0, %g1, %g0 ! Mycroft again...
bnz,pn %icc, .zerobyte ! non-zer, we have zero byte
add %i2, %g4, %l0 ! dst in ptr form
srl %l1, 16, %g1 ! first two bytes
sth %g1, [%l0]
ba .storehalfword
sth %l1, [%l0 + 2]
.forcenullunalign:
add %i2, %g4, %i2 ! single dst ptr
stb %g0, [%i2 - 1] ! store terminating null byte
.getstrlen:
sethi %hi(0x01010101), %i4 ! Mycroft...
or %i4, %lo(0x01010101), %i4
sll %i4, 7, %i5
.getstrlenloop:
andcc %i3, 3, %g0 ! word aligned?
bz,a,pn %icc, .searchword2 ! search word at a time
ld [%i3], %l1 ! src word
ldub [%i3], %l1 ! src byte
andcc %l1, 0xff, %g0 ! end of src?
bnz,a %icc, .getstrlenloop
add %i3, 1, %i3 ! src ++
sub %i3, %i1, %i0 ! len = src - orig src
ret
restore %i0, %g0, %o0
SET_SIZE(strlcpy)
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