view src/os/unix/ngx_gcc_atomic_amd64.h @ 394:05981f639d21 NGINX_0_7_9

nginx 0.7.9 *) Change: now ngx_http_charset_module works by default with following MIME types: text/html, text/css, text/xml, text/plain, text/vnd.wap.wml, application/x-javascript, and application/rss+xml. *) Feature: the "charset_types" and "addition_types" directives. *) Feature: now the "gzip_types", "ssi_types", and "sub_filter_types" directives use hash. *) Feature: the ngx_cpp_test_module. *) Feature: the "expires" directive supports daily time. *) Feature: the ngx_http_xslt_module improvements and bug fixing. Thanks to Denis F. Latypoff and Maxim Dounin. *) Bugfix: the "log_not_found" directive did not work for index files tests. *) Bugfix: HTTPS connections might hang, if kqueue, epoll, rtsig, or eventport methods were used; the bug had appeared in 0.7.7. *) Bugfix: if the "server_name", "valid_referers", and "map" directives used an "*.domain.tld" wildcard and exact name "domain.tld" was not set, then the exact name was matched by the wildcard; the bugs had appeared in 0.3.18.
author Igor Sysoev <http://sysoev.ru>
date Tue, 12 Aug 2008 00:00:00 +0400
parents 052a7b1d40e5
children
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/*
 * Copyright (C) Igor Sysoev
 */


#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")