Option -win64: Select Output Format Win64
Option -win64 makes JWasm produce an object module in PE32+ format, the 64-bit format used for Win64 binaries.Option -win64 will also set cpu to x86-64, model to FLAT and default calling convention to FASTCALL. This is to make JWasm compatible with Masm64 (ML64.EXE).
With OPTION WIN64, parameters specific to Win64 may be set.
For more information about Win64, see Win64 Output Format.
Chapter Output Formats lists all available output formats.