By default on OpenVMS VAX, invokes the VAX MACRO assembler to assemble
one or more assembly language source files. By default on OpenVMS Alpha
and OpenVMS I64, invokes the MACRO compiler for OpenVMS Systems to
compile VAX assembly language source files into native OpenVMS Alpha or
OpenVMS I64 object code.
The /ALPHA qualifier causes the MACRO command to invoke the MACRO-64
assembler if it is installed on Alpha.
The /MIGRATION qualifier is the default on Alpha and I64. On those
platforms, specifying MACRO is the same as specifying MACRO/MIGRATION.
For a complete description of the MACRO compiler for OpenVMS Systems,
see the HP OpenVMS MACRO Compiler Porting and User's Guide.