nginx 1.0.12 *) Feature: the "TLSv1.1" and "TLSv1.2" parameters of the "ssl_protocols" directive. *) Feature: the "if" SSI command supports captures in regular expressions. *) Bugfix: the "if" SSI command did not work inside the "block" command. *) Bugfix: in AIO error handling on FreeBSD. *) Bugfix: in the OpenSSL library initialization. *) Bugfix: the "worker_cpu_affinity" directive might not work. *) Bugfix: the "limit_conn_log_level" and "limit_req_log_level" directives might not work. *) Bugfix: the "read_ahead" directive might not work combined with "try_files" and "open_file_cache". *) Bugfix: the "proxy_cache_use_stale" directive with "error" parameter did not return answer from cache if there were no live upstreams. *) Bugfix: a segmentation fault might occur in a worker process if small time was used in the "inactive" parameter of the "proxy_cache_path" directive. *) Bugfix: responses from cache might hang. *) Bugfix: in error handling while connecting to a backend. Thanks to Piotr Sikora. *) Bugfix: in the "epoll" event method. Thanks to Yichun Zhang. *) Bugfix: the $sent_http_cache_control variable might contain a wrong value if the "expires" directive was used. Thanks to Yichun Zhang. *) Bugfix: the "limit_rate" directive did not allow to use full throughput, even if limit value was very high. *) Bugfix: the "sendfile_max_chunk" directive did not work, if the "limit_rate" directive was used. *) Bugfix: nginx could not be built on Solaris; the bug had appeared in 1.0.11. *) Bugfix: in the ngx_http_scgi_module. *) Bugfix: in the ngx_http_mp4_module.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#if (NGX_SMP)
#define NGX_SMP_LOCK  "lock;"
#else
#define NGX_SMP_LOCK
#endif


/*
 * "cmpxchgq  r, [m]":
 *
 *     if (rax == [m]) {
 *         zf = 1;
 *         [m] = r;
 *     } else {
 *         zf = 0;
 *         rax = [m];
 *     }
 *
 *
 * The "r" is any register, %rax (%r0) - %r16.
 * The "=a" and "a" are the %rax register.
 * Although we can return result in any register, we use "a" because it is
 * used in cmpxchgq anyway.  The result is actually in %al but not in $rax,
 * however as the code is inlined gcc can test %al as well as %rax.
 *
 * The "cc" means that flags were changed.
 */

static ngx_inline ngx_atomic_uint_t
ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
    ngx_atomic_uint_t set)
{
    u_char  res;

    __asm__ volatile (

         NGX_SMP_LOCK
    "    cmpxchgq  %3, %1;   "
    "    sete      %0;       "

    : "=a" (res) : "m" (*lock), "a" (old), "r" (set) : "cc", "memory");

    return res;
}


/*
 * "xaddq  r, [m]":
 *
 *     temp = [m];
 *     [m] += r;
 *     r = temp;
 *
 *
 * The "+r" is any register, %rax (%r0) - %r16.
 * The "cc" means that flags were changed.
 */

static ngx_inline ngx_atomic_int_t
ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add)
{
    __asm__ volatile (

         NGX_SMP_LOCK
    "    xaddq  %0, %1;   "

    : "+r" (add) : "m" (*value) : "cc", "memory");

    return add;
}


#define ngx_memory_barrier()    __asm__ volatile ("" ::: "memory")

#define ngx_cpu_pause()         __asm__ ("pause")