From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libjava/sysdep/x86-64/locks.h | 83 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 libjava/sysdep/x86-64/locks.h (limited to 'libjava/sysdep/x86-64') diff --git a/libjava/sysdep/x86-64/locks.h b/libjava/sysdep/x86-64/locks.h new file mode 100644 index 000000000..fdc0a3efb --- /dev/null +++ b/libjava/sysdep/x86-64/locks.h @@ -0,0 +1,83 @@ +/* locks.h - Thread synchronization primitives. X86/x86-64 implementation. + + Copyright (C) 2002 Free Software Foundation + + Contributed by Bo Thorsen . + + This file is part of libgcj. + +This software is copyrighted work licensed under the terms of the +Libgcj License. Please consult the file "LIBGCJ_LICENSE" for +details. */ + +#ifndef __SYSDEP_LOCKS_H__ +#define __SYSDEP_LOCKS_H__ + +typedef size_t obj_addr_t; /* Integer type big enough for object */ + /* address. */ + +// Atomically replace *addr by new_val if it was initially equal to old. +// Return true if the comparison succeeded. +// Assumed to have acquire semantics, i.e. later memory operations +// cannot execute before the compare_and_swap finishes. +inline static bool +compare_and_swap(volatile obj_addr_t *addr, + obj_addr_t old, + obj_addr_t new_val) +{ + char result; +#ifdef __x86_64__ + __asm__ __volatile__("lock; cmpxchgq %2, %0; setz %1" + : "=m"(*(addr)), "=q"(result) + : "r" (new_val), "a"(old), "m"(*addr) + : "memory"); +#else + __asm__ __volatile__("lock; cmpxchgl %2, %0; setz %1" + : "=m"(*addr), "=q"(result) + : "r" (new_val), "a"(old), "m"(*addr) + : "memory"); +#endif + return (bool) result; +} + +// Set *addr to new_val with release semantics, i.e. making sure +// that prior loads and stores complete before this +// assignment. +// On X86/x86-64, the hardware shouldn't reorder reads and writes, +// so we just have to convince gcc not to do it either. +inline static void +release_set(volatile obj_addr_t *addr, obj_addr_t new_val) +{ + __asm__ __volatile__(" " : : : "memory"); + *(addr) = new_val; +} + +// Compare_and_swap with release semantics instead of acquire semantics. +// On many architecture, the operation makes both guarantees, so the +// implementation can be the same. +inline static bool +compare_and_swap_release(volatile obj_addr_t *addr, + obj_addr_t old, + obj_addr_t new_val) +{ + 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 X86/x86-64, the hardware ensures that reads are properly ordered. +inline static void +read_barrier() +{ +} + +// Ensure that prior stores to memory are completed with respect to other +// processors. +inline static void +write_barrier() +{ + /* x86-64/X86 does not reorder writes. We just need to ensure that + gcc also doesn't. */ + __asm__ __volatile__(" " : : : "memory"); +} +#endif -- cgit v1.2.3