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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 "strcpy.s"
/*
* strcpy(s1, s2)
*
* Copy string s2 to s1. s1 must be large enough. Return s1.
*
* Fast assembler language version of the following C-program strcpy
* which represents the `standard' for the C-library.
*
* char *
* strcpy(s1, s2)
* register char *s1;
* register const char *s2;
* {
* char *os1 = s1;
*
* while(*s1++ = *s2++)
* ;
* return(os1);
* }
*
*/
#include <sys/asm_linkage.h>
! This implementation of strcpy works by first checking the
! source alignment and copying byte, half byte, or word
! quantities until the source ptr is aligned at an extended
! word boundary. Once this has occurred, the string is copied,
! checking for zero bytes, depending upon its dst ptr alignment.
! (methods for xword, word, half-word, and byte copies are present)
ENTRY(strcpy)
.align 32
sub %o1, %o0, %o3 ! src - dst
andcc %o1, 7, %o4 ! dword aligned ?
bz,pn %ncc, .srcaligned ! yup
mov %o0, %o2 ! save dst
.chkbyte:
andcc %o1, 1, %g0 ! need to copy byte ?
bz,pn %ncc, .chkhalfword ! nope, maybe halfword
sub %g0, %o1, %g1 ! %g1<2:0> = # of unaligned bytes
ldub [%o2 + %o3], %o5 ! src[0]
tst %o5 ! src[0] == 0 ?
stb %o5, [%o2] ! dst[0] = src[0]
bz,pn %ncc, .done ! yup, done
inc %o2 ! src++, dst++
.chkhalfword:
andcc %g1, 2, %g0 ! need to copy half-word ?
bz,pn %ncc, .chkword ! nope, maybe word
nop !
lduh [%o2 + %o3], %o5 ! load src halfword
srl %o5, 8, %o4 ! extract first byte
tst %o4 ! first byte == 0 ?
bz,pn %ncc, .done ! yup, done
stb %o4, [%o2] ! store first byte
andcc %o5, 0xff, %g0 ! extract second byte
stb %o5, [%o2 + 1] ! store second byte
bz,pn %ncc, .done ! yup, 2nd byte zero, done
add %o2, 2, %o2 ! src += 2
.chkword:
andcc %g1, 4, %g0 ! need to copy word ?
bz,pn %ncc, .srcaligned ! nope
nop !
lduw [%o2 + %o3], %o5 ! load src word
srl %o5, 24, %o4 ! extract first byte
tst %o4 ! is first byte zero ?
bz,pn %ncc, .done ! yup, done
stb %o4, [%o2] ! store first byte
srl %o5, 16, %o4 ! extract second byte
andcc %o4, 0xff, %g0 ! is second byte zero ?
bz,pn %ncc, .done ! yup, done
stb %o4, [%o2 + 1] ! store second byte
srl %o5, 8, %o4 ! extract third byte
andcc %o4, 0xff, %g0 ! third byte zero ?
bz,pn %ncc, .done ! yup, done
stb %o4, [%o2 + 2] ! store third byte
andcc %o5, 0xff, %g0 ! fourth byte zero ?
stb %o5, [%o2 + 3] ! store fourth byte
bz,pn %ncc, .done ! yup, fourth byte zero, done
add %o2, 4, %o2 ! src += 2
.srcaligned:
sethi %hi(0x01010101), %o4 ! Alan Mycroft's magic1
or %o4, %lo(0x01010101),%o4! finish loading magic1
sllx %o4, 32, %o1 ! spread magic1
and %o2, 3, %g4 ! dst<1:0> to examine offset
or %o4, %o1, %o4 ! to all 64 bits
cmp %g4, 1 ! dst offset of 1 or 5
sllx %o4, 7, %o5 ! Alan Mycroft's magic2
be,pn %ncc, .storebyte1241 ! store 1, 2, 4, 1 bytes
cmp %g4, 3 ! dst offset of 3 or 7
be,pn %ncc, .storebyte1421 ! store 1, 4, 2, 1 bytes
cmp %g4, 2 ! dst halfword aligned ?
be,pn %ncc, .storehalfword ! yup, store half-word wise
andcc %o2, 7, %g0 ! dst word aligned ?
bnz,pn %ncc, .storeword2 ! yup, store word wise
.empty
.storedword:
ldx [%o2 + %o3], %o1 ! src dword
add %o2, 8, %o2 ! src += 8, dst += 8
andn %o5, %o1, %g1 ! ~dword & 0x8080808080808080
sub %o1, %o4, %g4 ! dword - 0x0101010101010101
andcc %g4, %g1, %g0 ! ((dword - 0x0101010101010101) & ~dword & 0x8080808080808080)
bz,a,pt %ncc, .storedword ! no zero byte if magic expression == 0
stx %o1, [%o2 - 8] ! store word to dst (address pre-incremented)
.zerobyte:
orn %o4, %g0, %o4 ! 0xffffffffffffffff
sllx %o4, 56, %o4 ! 0xff00000000000000
srlx %o1, 56, %o3 ! %o3<7:0> = first byte
andcc %o1, %o4, %g0 ! first byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 8] ! store first byte
srlx %o4, 8, %o4 ! 0x00ff000000000000
srlx %o1, 48, %o3 ! %o3<7:0> = second byte
andcc %o1, %o4, %g0 ! second byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 7] ! store second byte
srlx %o4, 8, %o4 ! 0x0000ff0000000000
srlx %o1, 40, %o3 ! %o3<7:0> = third byte
andcc %o1, %o4, %g0 ! third byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 6] ! store third byte
srlx %o4, 8, %o4 ! 0x000000ff00000000
srlx %o1, 32, %o3 ! %o3<7:0> = fourth byte
andcc %o1, %o4, %g0 ! fourth byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 5] ! store fourth byte
srlx %o4, 8, %o4 ! 0x00000000ff000000
srlx %o1, 24, %o3 ! %o3<7:0> = fifth byte
andcc %o1, %o4, %g0 ! fifth byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 4] ! store fifth byte
srlx %o4, 8, %o4 ! 0x0000000000ff0000
srlx %o1, 16, %o3 ! %o3<7:0> = sixth byte
andcc %o1, %o4, %g0 ! sixth byte zero?
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 3] ! store sixth byte
srlx %o4, 8, %o4 ! 0x000000000000ff00
andcc %o1, %o4, %g0 ! seventh byte zero?
srlx %o1, 8, %o3 ! %o3<7:0> = seventh byte
bz,pn %ncc, .done ! yup, done
stb %o3, [%o2 - 2] ! store seventh byte
stb %o1, [%o2 - 1] ! store eigth byte
.done:
retl ! done with leaf function
nop ! ensure following loop 16-byte aligned
.storebyte1421:
ldx [%o2 + %o3], %o1 ! x = src[]
add %o2, 8, %o2 ! src += 8, dst += 8
andn %o5, %o1, %g1 ! ~x & 0x8080808080808080
sub %o1, %o4, %g4 ! x - 0x0101010101010101
andcc %g4, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases
srlx %o1, 56, %g1 ! %g1<7:0> = first byte; word aligned now
stb %g1, [%o2 - 8] ! store first byte
srlx %o1, 24, %g1 ! %g1<31:0> = bytes 2, 3, 4, 5
stw %g1, [%o2 - 7] ! store bytes 2, 3, 4, 5
srlx %o1, 8, %g1 ! %g1<15:0> = bytes 6, 7
sth %g1, [%o2 - 3] ! store bytes 6, 7
ba .storebyte1421 ! next dword
stb %o1, [%o2 - 1] ! store eigth byte
nop ! ensure following loop 16-byte aligned
nop ! ensure following loop 16-byte aligned
.storebyte1241:
ldx [%o2 + %o3], %o1 ! x = src[]
add %o2, 8, %o2 ! src += 8, dst += 8
andn %o5, %o1, %g1 ! ~x & 0x8080808080808080
sub %o1, %o4, %g4 ! x - 0x0101010101010101
andcc %g4, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases
srlx %o1, 56, %g1 ! %g1<7:0> = first byte; word aligned now
stb %g1, [%o2 - 8] ! store first byte
srlx %o1, 40, %g1 ! %g1<15:0> = bytes 2, 3
sth %g1, [%o2 - 7] ! store bytes 2, 3
srlx %o1, 8, %g1 ! %g1<31:0> = bytes 4, 5, 6, 7
stw %g1, [%o2 - 5] ! store bytes 4, 5, 6, 7
ba .storebyte1241 ! next dword
stb %o1, [%o2 - 1] ! store eigth byte
nop ! ensure following loop 16-byte aligned
nop ! ensure following loop 16-byte aligned
.storehalfword:
ldx [%o2 + %o3], %o1 ! x = src[]
add %o2, 8, %o2 ! src += 8, dst += 8
andn %o5, %o1, %g1 ! ~x & 0x8080808080808080
sub %o1, %o4, %g4 ! x - 0x0101010101010101
andcc %g4, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases
srlx %o1, 48, %g1 ! get first and second byte
sth %g1, [%o2 - 8] ! store first and second byte; word aligned now
srlx %o1, 16, %g1 ! %g1<31:0> = bytes 3, 4, 5, 6
stw %g1, [%o2 - 6] ! store bytes 3, 4, 5, 6
ba .storehalfword ! next word
sth %o1, [%o2 - 2] ! store seventh and eigth byte
.storeword:
ldx [%o2 + %o3], %o1 ! x = src[]
.storeword2:
add %o2, 8, %o2 ! src += 8, dst += 8
andn %o5, %o1, %g1 ! ~x & 0x0x8080808080808080
sub %o1, %o4, %g4 ! x - 0x0101010101010101
andcc %g4, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases
srlx %o1, 32, %g1 ! get bytes 1,2,3,4
stw %g1, [%o2 - 8] ! store bytes 1,2,3,4 (address is pre-incremented)
ba .storeword ! no zero byte if magic expression == 0
stw %o1, [%o2 - 4] ! store bytes 5,6,7,8
nop ! padding, do not remove!!!
nop ! padding, do not remove!!!
SET_SIZE(strcpy)
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