From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13902 invoked by alias); 15 Jun 2012 08:08:50 -0000 Received: (qmail 13889 invoked by uid 22791); 15 Jun 2012 08:08:47 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE X-Spam-Check-By: sourceware.org Received: from mail-out.m-online.net (HELO mail-out.m-online.net) (212.18.0.9) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 15 Jun 2012 08:08:34 +0000 Received: from frontend1.mail.m-online.net (unknown [192.168.8.180]) by mail-out.m-online.net (Postfix) with ESMTP id 3WDDq52cgRz4KMmj for ; Fri, 15 Jun 2012 10:08:32 +0200 (CEST) Received: from igel.home (ppp-93-104-149-63.dynamic.mnet-online.de [93.104.149.63]) by mail.mnet-online.de (Postfix) with ESMTPA id 3WDDq46Wvlz4KK9v for ; Fri, 15 Jun 2012 10:08:32 +0200 (CEST) Received: by igel.home (Postfix, from userid 501) id 94488CA2A4; Fri, 15 Jun 2012 10:08:32 +0200 (CEST) From: Andreas Schwab To: java-patches@gcc.gnu.org Subject: Update libjava/sysdep/m68k/locks.h with new atomic builtins References: X-Yow: Thousands of days of civilians ... have produced a... feeling for the aesthetic modules -- Date: Fri, 15 Jun 2012 08:08:00 -0000 In-Reply-To: (Uros Bizjak's message of "Thu, 14 Jun 2012 11:41:30 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Mailing-List: contact java-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: java-patches-owner@gcc.gnu.org X-SW-Source: 2012-q2/txt/msg00021.txt.bz2 There is not much to gain, the builtin generates pretty much the same code. Tested on m68k-linux and checked in. Andreas. * sysdep/m68k/locks.h (compare_and_swap): Use __sync_bool_compare_and_swap. (release_set): Use write_barrier instead of inlining it. diff --git a/libjava/sysdep/m68k/locks.h b/libjava/sysdep/m68k/locks.h index d70757a..b51e314 100644 --- a/libjava/sysdep/m68k/locks.h +++ b/libjava/sysdep/m68k/locks.h @@ -1,6 +1,6 @@ // locks.h - Thread synchronization primitives. m68k implementation. -/* Copyright (C) 2006 Free Software Foundation +/* Copyright (C) 2006, 2012 Free Software Foundation This file is part of libgcj. @@ -22,12 +22,24 @@ static inline bool compare_and_swap(volatile obj_addr_t *addr, obj_addr_t old, obj_addr_t new_val) { - char result; - __asm__ __volatile__("cas.l %2,%3,%0; seq %1" - : "+m" (*addr), "=d" (result), "+d" (old) - : "d" (new_val) - : "memory"); - return (bool) result; + return __sync_bool_compare_and_swap (addr, old, new_val); +} + +// Ensure that subsequent instructions do not execute on stale +// data that was loaded from memory before the barrier. +// On m68k, the hardware ensures that reads are properly ordered. +static inline void +read_barrier(void) +{ +} + +// Ensure that prior stores to memory are completed with respect to other +// processors. +static inline void +write_barrier(void) +{ + // m68k does not reorder writes. We just need to ensure that gcc also doesn't. + __asm__ __volatile__(" " : : : "memory"); } // Set *addr to new_val with release semantics, i.e. making sure @@ -38,8 +50,8 @@ compare_and_swap(volatile obj_addr_t *addr, static inline void release_set(volatile obj_addr_t *addr, obj_addr_t new_val) { - __asm__ __volatile__(" " : : : "memory"); - *(addr) = new_val; + write_barrier (); + *addr = new_val; } // Compare_and_swap with release semantics instead of acquire semantics. @@ -53,20 +65,4 @@ compare_and_swap_release(volatile obj_addr_t *addr, return compare_and_swap(addr, old, new_val); } -// Ensure that subsequent instructions do not execute on stale -// data that was loaded from memory before the barrier. -// On m68k, the hardware ensures that reads are properly ordered. -static inline void -read_barrier(void) -{ -} - -// Ensure that prior stores to memory are completed with respect to other -// processors. -static inline void -write_barrier(void) -{ - // m68k does not reorder writes. We just need to ensure that gcc also doesn't. - __asm__ __volatile__(" " : : : "memory"); -} #endif -- 1.7.10.4 -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."