Several new directives enable or disable various aspects of the assembler control, such as the new 80486 coprocessor instructions and use of compatibility options.
The new OPTION directive allows you to selectively define the assembler's behavior, including the enabling of compatibility with MASM 5.1. See Sections 1.3.2, “Using the OPTION Directive,” and A.2, “Compatibility between MASM 5.1 and 6.0.”
The new .NO87 directive disables all coprocessor instructions. See online help for more information.
To enable the 80486 instructions, use the new .486 directive. The .486P directive enables 80486 instructions at the highest privilege level (recommended for systems-level programs only). See online help for more information.
The PUSHCONTEXT and POPCONTEXT Directives
The directive PUSHCONTEXT saves the assembly environment, and POPCONTEXT restores it. The environment includes the segment register assumes, the radix, the listing and CREF flags, and the current processor and coprocessor. Note that .NOCREF (the MASM equivalent to .XCREF) still determines whether information for a given symbol will be added to Browser information and to the symbol table in the listing file. See Appendix C or online help for more information on listing files.