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diff src/os/unix/ngx_gcc_atomic_amd64.h @ 274:052a7b1d40e5 NGINX_0_5_7

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nginx 0.5.7 *) Feature: the ssl_session_cache storage optimization. *) Bugfixes in the "ssl_session_cache" and "limit_zone" directives. *) Bugfix: the segmentation fault was occurred on start or while reconfiguration if the "ssl_session_cache" or "limit_zone" directives were used on 64-bit platforms. *) Bugfix: a segmentation fault occurred if the "add_before_body" or "add_after_body" directives were used and there was no "Content-Type" header line in response. *) Bugfix: the OpenSSL library was always built with the threads support. Thanks to Den Ivanov. *) Bugfix: the PCRE-6.5+ library and the icc compiler compatibility.
author Igor Sysoev <http://sysoev.ru>
date Mon, 15 Jan 2007 00:00:00 +0300
parents 73e8476f9142
children d0f7a625f27c
line wrap: on
line diff
--- a/src/os/unix/ngx_gcc_atomic_amd64.h
+++ b/src/os/unix/ngx_gcc_atomic_amd64.h
@@ -24,8 +24,11 @@
  *
  *
  * 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 %rax because it is used in cmpxchgq anyway.
+ * 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.
  */
 
@@ -33,14 +36,13 @@ 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)
 {
-    ngx_atomic_uint_t  res;
+    u_char  res;
 
     __asm__ volatile (
 
          NGX_SMP_LOCK
     "    cmpxchgq  %3, %1;   "
-    "    setz      %b0;      "
-    "    movzbq    %b0, %0;  "
+    "    sete      %0;       "
 
     : "=a" (res) : "m" (*lock), "a" (old), "r" (set) : "cc", "memory");
 
@@ -68,7 +70,7 @@ ngx_atomic_fetch_add(ngx_atomic_t *value
          NGX_SMP_LOCK
     "    xaddq  %0, %1;   "
 
-    : "+q" (add) : "m" (*value) : "cc", "memory");
+    : "+r" (add) : "m" (*value) : "cc", "memory");
 
     return add;
 }