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<title>delta/glibc.git/sysdeps/i386/i586/strcpy.S, branch azanella/aarch64-split-stack</title>
<subtitle>sourceware.org: git/glibc.git
</subtitle>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/'/>
<entry>
<title>Update copyright dates with scripts/update-copyrights.</title>
<updated>2018-01-01T00:32:25+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2018-01-01T00:32:25+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=688903eb3ef01301d239ab753d309d45720610a7'/>
<id>688903eb3ef01301d239ab753d309d45720610a7</id>
<content type='text'>
	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.
</content>
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	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.
</pre>
</div>
</content>
</entry>
<entry>
<title>i586: Use conditional branches in strcpy.S [BZ #22353]</title>
<updated>2017-10-30T17:02:30+00:00</updated>
<author>
<name>H.J. Lu</name>
<email>hjl.tools@gmail.com</email>
</author>
<published>2017-10-30T17:02:16+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=c5cc45148c89cc5c57d1946348dd242d4db5c5f5'/>
<id>c5cc45148c89cc5c57d1946348dd242d4db5c5f5</id>
<content type='text'>
i586 strcpy.S used a clever trick with LEA to implement jump table:

/* ECX has the last 2 bits of the address of source - 1.  */
	andl	$3, %ecx

        call    2f
2:      popl    %edx
	/* 0xb is the distance between 2: and 1:.  */
        leal    0xb(%edx,%ecx,8), %ecx
        jmp     *%ecx

        .align 8
1:  /* ECX == 0 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 1 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 2 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 3 */
L(1):   movl    (%esi), %ecx
        leal    4(%esi),%esi

This fails if there are instruction length changes before L(1):.  This
patch replaces it with conditional branches:

	cmpb	$2, %cl
	je	L(Src2)
	ja	L(Src3)
	cmpb	$1, %cl
	je	L(Src1)

L(Src0):

which have similar performance and work with any instruction lengths.

Tested on i586 and i686 with and without --disable-multi-arch.

	[BZ #22353]
	* sysdeps/i386/i586/strcpy.S (STRCPY): Use conditional branches.
	(1): Renamed to ...
	(L(Src0)): This.
	(L(Src1)): New.
	(L(Src2)): Likewise.
	(L(1)): Renamed to ...
	(L(Src3)): This.
</content>
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<pre>
i586 strcpy.S used a clever trick with LEA to implement jump table:

/* ECX has the last 2 bits of the address of source - 1.  */
	andl	$3, %ecx

        call    2f
2:      popl    %edx
	/* 0xb is the distance between 2: and 1:.  */
        leal    0xb(%edx,%ecx,8), %ecx
        jmp     *%ecx

        .align 8
1:  /* ECX == 0 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 1 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 2 */
        orb     (%esi), %al
        jz      L(end)
        stosb
        xorl    %eax, %eax
        incl    %esi
    /* ECX == 3 */
L(1):   movl    (%esi), %ecx
        leal    4(%esi),%esi

This fails if there are instruction length changes before L(1):.  This
patch replaces it with conditional branches:

	cmpb	$2, %cl
	je	L(Src2)
	ja	L(Src3)
	cmpb	$1, %cl
	je	L(Src1)

L(Src0):

which have similar performance and work with any instruction lengths.

Tested on i586 and i686 with and without --disable-multi-arch.

	[BZ #22353]
	* sysdeps/i386/i586/strcpy.S (STRCPY): Use conditional branches.
	(1): Renamed to ...
	(L(Src0)): This.
	(L(Src1)): New.
	(L(Src2)): Likewise.
	(L(1)): Renamed to ...
	(L(Src3)): This.
</pre>
</div>
</content>
</entry>
<entry>
<title>Update copyright dates with scripts/update-copyrights.</title>
<updated>2017-01-01T00:14:16+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2017-01-01T00:14:16+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=bfff8b1becd7d01c074177df7196ab327cd8c844'/>
<id>bfff8b1becd7d01c074177df7196ab327cd8c844</id>
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<pre>
</pre>
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</entry>
<entry>
<title>Update copyright dates with scripts/update-copyrights.</title>
<updated>2016-01-04T16:05:18+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2016-01-04T16:05:18+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=f7a9f785e547bd599dee496fd906a28bcb4ec7fe'/>
<id>f7a9f785e547bd599dee496fd906a28bcb4ec7fe</id>
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<pre>
</pre>
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</entry>
<entry>
<title>Update copyright dates with scripts/update-copyrights.</title>
<updated>2015-01-02T16:29:47+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2015-01-02T16:28:19+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=b168057aaacf1d149246d0eb3e84332492d35063'/>
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</entry>
<entry>
<title>Update copyright notices with scripts/update-copyrights</title>
<updated>2014-01-01T12:00:23+00:00</updated>
<author>
<name>Allan McRae</name>
<email>allan@archlinux.org</email>
</author>
<published>2014-01-01T11:03:15+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=d4697bc93dc27a7bbf275ce7dd351bb1bfcf28de'/>
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</pre>
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</content>
</entry>
<entry>
<title>Remove remaining bounded-pointers support from i386 .S files.</title>
<updated>2013-02-21T22:21:52+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2013-02-21T22:21:52+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=2366713d874342c94f9362b0d6b2461e1c68dbc3'/>
<id>2366713d874342c94f9362b0d6b2461e1c68dbc3</id>
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</pre>
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</entry>
<entry>
<title>Remove some bounded-pointers support from i386 .S files.</title>
<updated>2013-02-19T21:58:08+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2013-02-19T21:58:08+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=92945b5261c412eb590b2b34c7ec9a035f0693a1'/>
<id>92945b5261c412eb590b2b34c7ec9a035f0693a1</id>
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</entry>
<entry>
<title>Update copyright notices with scripts/update-copyrights.</title>
<updated>2013-01-02T19:05:09+00:00</updated>
<author>
<name>Joseph Myers</name>
<email>joseph@codesourcery.com</email>
</author>
<published>2013-01-02T19:01:50+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=568035b7874a099087b77f7bba3e36a1173787b0'/>
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</entry>
<entry>
<title>Replace FSF snail mail address with URLs.</title>
<updated>2012-02-09T23:18:22+00:00</updated>
<author>
<name>Paul Eggert</name>
<email>eggert@cs.ucla.edu</email>
</author>
<published>2012-02-09T23:18:22+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/glibc.git/commit/?id=59ba27a63ada3f46b71ec99a314dfac5a38ad6d2'/>
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