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Atomic operations for PA
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- To: gcc-patches at gcc dot gnu dot org, libstdc++ at gcc dot gnu dot org
- Date: Tue, 5 Nov 2002 12:24:37 -0500 (EST)
- Subject: Atomic operations for PA
The enclosed patch adds __exchange_and_add and __atomic_add to libstdc++
for the PA. It is based on a patch that Alan Modra sent me. However,
it wasn't fully ansi compatible and it didn't work with 32-bit hpux.
So, I rewrote the locking asm and added code to allow for explicit
instantiantion of the lock structure under hpux.
The PA has only one atomic instruction and the address it uses must
be 16-byte aligned. Thus, we need an atomicity lock structure. Since
the 32-bit hpux port doesn't support weak, I had to explicitly
instantiate it somewhere. I picked src/misc-inst.cc as it seemed
to contain other miscellaneous instantiations. I realize that
this is somewhat ugly but I don't see any way around this.
The patch has been tested on hppa-unknown-linux-gnu, hppa2.0-hp-hpux11*,
and hppa64-hp-hpux11*. There are no regressions and under hppa-linux
it appears to fix pthread[2-3].cc.
Ok for main.
Dave
--
J. David Anglin dave.anglin@nrc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)
2002-11-05 John David Anglin <dave@hiauly1.hia.nrc.ca>
* configure.target (hppa*): Define cpu_include_dir.
* config/os/hpux/os_defines.h (_GLIBCPP_INST_ATOMICITY_LOCK): Define.
* src/misc-inst.cc (std): Instantiate atomicity lock when
_GLIBCPP_INST_ATOMICITY_LOCK is defined.
* config/cpu/hppa/atomicity.h: New file.
Index: configure.target
===================================================================
RCS file: /cvsroot/gcc/gcc/libstdc++-v3/configure.target,v
retrieving revision 1.54
diff -u -3 -p -r1.54 configure.target
--- configure.target 2 Nov 2002 01:42:21 -0000 1.54
+++ configure.target 4 Nov 2002 21:17:15 -0000
@@ -72,6 +72,9 @@ case "${target_cpu}" in
athlon* | i586 | i686 | i786 | x86_64)
cpu_include_dir="cpu/i486"
;;
+ hppa*)
+ cpu_include_dir="cpu/hppa"
+ ;;
m680[246]0)
cpu_include_dir="cpu/m68k"
;;
Index: config/os/hpux/os_defines.h
===================================================================
RCS file: /cvsroot/gcc/gcc/libstdc++-v3/config/os/hpux/os_defines.h,v
retrieving revision 1.3
diff -u -3 -p -r1.3 os_defines.h
--- config/os/hpux/os_defines.h 26 Sep 2002 05:25:10 -0000 1.3
+++ config/os/hpux/os_defines.h 4 Nov 2002 21:17:15 -0000
@@ -84,4 +84,8 @@ namespace std
typedef long int __padding_type;
#endif
+/* We need explicit instantiation of the atomicity lock on 32-bit HPUX. */
+#ifndef __LP64__
+#define _GLIBCPP_INST_ATOMICITY_LOCK 1
+#endif
#endif
Index: src/misc-inst.cc
===================================================================
RCS file: /cvsroot/gcc/gcc/libstdc++-v3/src/misc-inst.cc,v
retrieving revision 1.19
diff -u -3 -p -r1.19 misc-inst.cc
--- src/misc-inst.cc 9 Sep 2002 20:26:42 -0000 1.19
+++ src/misc-inst.cc 4 Nov 2002 21:17:15 -0000
@@ -37,6 +37,7 @@
#include <ostream>
#include <algorithm>
#include <vector>
+#include <bits/atomicity.h>
namespace std
{
@@ -66,6 +67,9 @@ namespace std
template
basic_istream<wchar_t>&
getline(basic_istream<wchar_t>&, wstring&);
+#endif
+#ifdef _GLIBCPP_INST_ATOMICITY_LOCK
+ template volatile int __Atomicity_lock<0>::_S_atomicity_lock;
#endif
#if 1
--- /dev/null Mon Nov 4 16:19:42 2002
+++ config/cpu/hppa/atomicity.h Mon Nov 4 16:09:50 2002
@@ -0,0 +1,87 @@
+/* Low-level functions for atomic operations. PA-RISC version. -*- C++ -*-
+ Copyright 2002 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#ifndef _BITS_ATOMICITY_H
+#define _BITS_ATOMICITY_H 1
+
+typedef int _Atomic_word;
+
+template <int __inst>
+struct __Atomicity_lock
+{
+ static volatile int __attribute__ ((aligned (16))) _S_atomicity_lock;
+};
+
+template <int __inst>
+volatile int __Atomicity_lock<__inst>::_S_atomicity_lock = 1;
+
+/* Because of the lack of weak support when using the hpux
+ som linker, we explicitly instantiate the atomicity lock
+ in src/misc-inst.cc when _GLIBCPP_INST_ATOMICITY_LOCK
+ is defined. */
+#ifndef _GLIBCPP_INST_ATOMICITY_LOCK
+template volatile int __Atomicity_lock<0>::_S_atomicity_lock;
+#endif
+
+static inline int
+__attribute__ ((__unused__))
+__exchange_and_add (volatile _Atomic_word* __mem, int __val)
+{
+ _Atomic_word result;
+ int tmp;
+ volatile int& lock = __Atomicity_lock<0>::_S_atomicity_lock;
+
+ __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
+ "cmpib,<>,n 0,%0,.+20\n\t"
+ "ldw 0(%1),%0\n\t"
+ "cmpib,= 0,%0,.-4\n\t"
+ "nop\n\t"
+ "b,n .-20"
+ : "=&r" (tmp)
+ : "r" (&lock));
+
+ result = *__mem;
+ *__mem = result + __val;
+ __asm__ __volatile__("");
+ lock = tmp;
+ return result;
+}
+
+static inline void
+__attribute__ ((__unused__))
+__atomic_add (_Atomic_word* __mem, int __val)
+{
+ int tmp;
+ volatile int& lock = __Atomicity_lock<0>::_S_atomicity_lock;
+
+ __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
+ "cmpib,<>,n 0,%0,.+20\n\t"
+ "ldw 0(%1),%0\n\t"
+ "cmpib,= 0,%0,.-4\n\t"
+ "nop\n\t"
+ "b,n .-20"
+ : "=&r" (tmp)
+ : "r" (&lock));
+
+ *__mem += __val;
+ __asm__ __volatile__("");
+ lock = tmp;
+}
+
+#endif