diff options
| author | Nate Begeman <natebegeman@mac.com> | 2009-01-26 02:54:45 +0000 |
|---|---|---|
| committer | Nate Begeman <natebegeman@mac.com> | 2009-01-26 02:54:45 +0000 |
| commit | 34509841e747f155adea8608af727e1a83c35dae (patch) | |
| tree | 1417ce55f80c4c7c444c56c4c28ff06e3f5bd357 | |
| parent | 18f02318a65e176cb165ccff97478a7967aeef86 (diff) | |
| download | llvm-34509841e747f155adea8608af727e1a83c35dae.tar.gz llvm-34509841e747f155adea8608af727e1a83c35dae.tar.bz2 llvm-34509841e747f155adea8608af727e1a83c35dae.tar.xz | |
Add some documentation for address-space-based access to the segment registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62986 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | docs/CodeGenerator.html | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/docs/CodeGenerator.html b/docs/CodeGenerator.html index 009ecd6767..66d793dfa0 100644 --- a/docs/CodeGenerator.html +++ b/docs/CodeGenerator.html @@ -1718,7 +1718,7 @@ processors, and includes support for ISA extensions such as MMX and SSE. <!-- _______________________________________________________________________ --> <div class="doc_subsubsection"> - <a name="x86_tt">X86 Target Triples Supported</a> + <a name="x86_tt">X86 Target Triples supported</a> </div> <div class="doc_text"> @@ -1791,6 +1791,27 @@ same way and in the same order.</p> <!-- _______________________________________________________________________ --> <div class="doc_subsubsection"> + <a name="x86_memory">X86 address spaces supported</a> +</div> + +<div class="doc_text"> + +<p>x86 has the ability to perform loads and stores to different address spaces +via the x86 segment registers. A segment override prefix byte on an instruction +causes the instruction's memory access to go to the specified segment. LLVM +address space 0 is the default address space, which includes the stack, and +any unqualified memory accesses in a program. Address spaces 1-255 are +currently reserved for user-defined code. The GS-segment is represented by +address space 256. Other x86 segments have yet to be allocated address space +numbers. + +<p>Some operating systems use the GS-segment to implement TLS, so care should be +taken when reading and writing to address space 256 on these platforms. + +</div> + +<!-- _______________________________________________________________________ --> +<div class="doc_subsubsection"> <a name="x86_names">Instruction naming</a> </div> |