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Date:      Mon, 10 Aug 2015 03:21:09 +1000 (EST)
From:      Bruce Evans <brde@optusnet.com.au>
To:        Warner Losh <imp@bsdimp.com>
Cc:        Dimitry Andric <dim@freebsd.org>, src-committers@freebsd.org,  svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r286519 - head/contrib/binutils/gas/config
Message-ID:  <20150810030920.K3557@besplex.bde.org>
In-Reply-To: <FE48F62E-79C9-48D6-B2EA-21544EC19C45@bsdimp.com>
References:  <201508091106.t79B6fGN078307@repo.freebsd.org> <FE48F62E-79C9-48D6-B2EA-21544EC19C45@bsdimp.com>

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On Sun, 9 Aug 2015, Warner Losh wrote:

> Since when is LEFT shifting a signed number undefined. It is RIGHT
> shifting that=E2=80=99s undefined=E2=80=A6

Always.  It always shifts out the sign bit in the usual 2's complement
representation, so must be undefined in that case.  It is undefined by
definition in other representions where the sign bit could have been
anywhere before C99.  Left shifting of a positive value is undefined
if the shift moves a bit into or through the sign bit.

Strangely, right shifting is never undefined.  It is implementation-
defined.  Now the sign bit may or may not be preserved or take part
in the shift, but other bits are never shifted into the sign bit
except possibly in weird pre-C99 representations, so overflow doesn't
occur and the usual reason for undefined behaviour of an expression --
that the correct result is unrepresentable -- doesn't apply.

I remembered this backwards too.

Bruce
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From: Warner Losh <imp@FreeBSD.org>
Date: Sun, 9 Aug 2015 18:15:34 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r286536 - head
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Author: imp
Date: Sun Aug  9 18:15:33 2015
New Revision: 286536
URL: https://svnweb.freebsd.org/changeset/base/286536

Log:
  cmp and cp are used by the kerberos install, so need to be imclided in
  ITOOLS. They are tiny enough that I'm not making conditional: the
  minuscule savings in disk space isn't worth the obfuscation of
  Makefile.inc1.

Modified:
  head/Makefile.inc1

Modified: head/Makefile.inc1
==============================================================================
--- head/Makefile.inc1	Sun Aug  9 17:08:18 2015	(r286535)
+++ head/Makefile.inc1	Sun Aug  9 18:15:33 2015	(r286536)
@@ -807,7 +807,7 @@ __installcheck_UGID:
 _zoneinfo=	zic tzsetup
 .endif
 
-ITOOLS=	[ awk cap_mkdb cat chflags chmod chown \
+ITOOLS=	[ awk cap_mkdb cat chflags chmod chown cmp cp \
 	date echo egrep find grep id install ${_install-info} \
 	ln lockf make mkdir mtree mv pwd_mkdb \
 	rm sed services_mkdb sh strip sysctl test true uname wc ${_zoneinfo} \



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