1  X86-64 Assembler

The minimum required OpenVMS version for this kit is OpenVMS V9.2-2.

PLEASE NOTE:
This release of X86ASM added the feature to prefix each compiler message with:
%facility-severity-ident followed by the actual message text. Due to an
oversight, X86ASM (SYS$SYSTEM:LLVM-MC.EXE) incorrectly reports itself as CXX
instead of LLVMMC. The message is still correct and the generated code is still
the same as before. It is just a cosmetic mistake. We will correct this in the
next release.


This kit includes the LLVM tool  named  "llvm-mc".   This  provides  a
native  x86-64  assembler that is highly compatible with the gnu "gas"
assembler.

It needs to be activated as a "foreign command". Use the following command
to create the foreign command:
  $ llvmmc :== $sys$system:llvm-mc

The compiler version number is:

$ llvmmc --version
LLVM (http://llvm.org/):
  VSI version V10.1-3
  LLVM version 10.0.1
  Optimized build.
  Build date: 09-12-2025
  Target: x86_64-OpenVMS


A sample command is:

$ llvmmc --filetype=obj -o=objectfilename.obj sourcefilename.s

Some useful options:

   --help
   Display available options (help-hidden for more).

   -o <filename>
   Use <filename> as the output filename. See the summary above for more details.

   --filetype=[asm,null,obj]
   Sets the output filetype. Setting this flag to asm will make the tool output
   text assembly. Setting this flag to obj will make the tool output an object
   file. Setting it to null causes no output to be created and can be used for
   timing purposes. The default value is asm.

   --assemble
   Assemble assembly file (default), and print the result to assembly. This is
   useful to design and test instruction parsers, and can be a useful tool when
   combined with other llvm-mc flags. For example, this option may be useful to
   transcode assembly from different dialects, e.g. on Intel where you can use
   -output-asm-variant=1 to translate from AT&T to Intel assembly syntax. It can
   also be combined with show-encoding to understand how instructions are
   encoded.

   --disassemble
   Parse a series of hex bytes, and print the result out as assembly syntax.


1.1  Documentation

Documentation for the assembler can be found at https://llvm.org/docs/CommandGuide/llvm-mc.html