diff options
Diffstat (limited to 'sysdeps/x86_64/bits/atomic.h')
| -rw-r--r-- | sysdeps/x86_64/bits/atomic.h | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/sysdeps/x86_64/bits/atomic.h b/sysdeps/x86_64/bits/atomic.h index f72f16c501..22d3ab0267 100644 --- a/sysdeps/x86_64/bits/atomic.h +++ b/sysdeps/x86_64/bits/atomic.h @@ -1,4 +1,4 @@ -/* Copyright (C) 2002 Free Software Foundation, Inc. +/* Copyright (C) 2002, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -84,6 +84,28 @@ typedef uintmax_t uatomic_max_t; ret; }) +/* Note that we need no lock prefix. */ +#define atomic_exchange(mem, newvalue) \ + ({ __typeof (*mem) result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile ("xchgb %b0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "1" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile ("xchgw %w0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "1" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile ("xchgl %0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "1" (*mem)); \ + else \ + __asm __volatile ("xchgq %q0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "1" (*mem)); \ + result; }) + + #define atomic_exchange_and_add(mem, value) \ ({ __typeof (*mem) result; \ if (sizeof (*mem) == 1) \ |