Magic-Mirror/llvm-capstone
1
0
Fork 0
mirror of https://github.com/capstone-engine/llvm-capstone.git synced 2025-02-08 10:30:09 +00:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

Update atomic Design A spec

Browse Source 
llvm-svn: 116707
This commit is contained in:
Howard Hinnant 2010-10-18 16:02:24 +00:00
parent 8b6b189422
commit 1f1f63a698
1 changed files with 42 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
libcxx/www/atomic_design_a.html
View File

@ -36,21 +36,34 @@
<!--*********************************************************************-->
<p>
This is more of a synopsis than a true description. The compiler supplies all
of the intrinsics as described below. This list of intrinsics roughly parallels
the requirements of the C and C++ atomics proposals. The C and C++ library
imlpementations simply drop through to these intrinsics. Anything the platform
does not support in hardware, the compiler arranges for a (compiler-rt) library
call to be made which will do the job with a mutex, and in this case ignoring
the memory ordering parameter.
The compiler supplies all of the intrinsics as described below. This list of
intrinsics roughly parallels the requirements of the C and C++ atomics
proposals. The C and C++ library imlpementations simply drop through to these
intrinsics. Anything the platform does not support in hardware, the compiler
arranges for a (compiler-rt) library call to be made which will do the job with
a mutex, and in this case ignoring the memory ordering parameter (effectively
implementing <tt>memory_order_seq_cst</tt>).
</p>
<p>
Ultimate efficiency is preferred over run time error checking. Undefined
behavior is acceptable when the inputs do not conform as defined below.
</p>
<blockquote><pre>
<font color="#C80000">// In every intrinsic signature below, type* atomic_obj may be a pointer to a</font>
<font color="#C80000">// volatile-qualifed type.</font>
<font color="#C80000">// Memory ordering values map to the following meanings:</font>
<font color="#C80000">// memory_order_relaxed == 0</font>
<font color="#C80000">// memory_order_consume == 1</font>
<font color="#C80000">// memory_order_acquire == 2</font>
<font color="#C80000">// memory_order_release == 3</font>
<font color="#C80000">// memory_order_acq_rel == 4</font>
<font color="#C80000">// memory_order_seq_cst == 5</font>
<font color="#C80000">// type must be trivially copyable</font>
bool __atomic_is_lock_free(const type* atomic_obj);
<font color="#C80000">// type represents a "type argument"</font>
bool __atomic_is_lock_free(type);
<font color="#C80000">// type must be trivially copyable</font>
<font color="#C80000">// Behavior is defined for mem_ord = 0, 1, 2, 5</font>
@ -67,6 +80,8 @@ type __atomic_exchange(type* atomic_obj, type desired, int mem_ord);
<font color="#C80000">// type must be trivially copyable</font>
<font color="#C80000">// Behavior is defined for mem_success = [0 ... 5],</font>
<font color="#C80000">// mem_falure &lt;= mem_success</font>
<font color="#C80000">// mem_falure != 3</font>
<font color="#C80000">// mem_falure != 4</font>
bool __atomic_compare_exchange_strong(type* atomic_obj,
type* expected, type desired,
int mem_success, int mem_failure);
@ -74,6 +89,8 @@ bool __atomic_compare_exchange_strong(type* atomic_obj,
<font color="#C80000">// type must be trivially copyable</font>
<font color="#C80000">// Behavior is defined for mem_success = [0 ... 5],</font>
<font color="#C80000">// mem_falure &lt;= mem_success</font>
<font color="#C80000">// mem_falure != 3</font>
<font color="#C80000">// mem_falure != 4</font>
bool __atomic_compare_exchange_weak(type* atomic_obj,
type* expected, type desired,
int mem_success, int mem_failure);
@ -124,9 +141,25 @@ this argument to 5.
<p>
If desired the intrinsics taking two ordering parameters can default
<tt>mem_success</tt> to 5, and <tt>mem_failure</tt> to <tt>mem_success</tt>.
<tt>mem_success</tt> to 5, and <tt>mem_failure</tt> to
<tt>translate_memory_order(mem_success)</tt> where
<tt>translate_memory_order(mem_success)</tt> is defined as:
</p>
<blockquote><pre>
int
translate_memory_order(int o)
{
switch (o)
{
case 4:
return 2;
case 3:
return 0;
}
return o;
}
</pre></blockquote>
</div>
</body>
</html>