`.OPT`

Directive that changes assembler options. The only options allowed are:

Option name | Importance
Proc6502 | selecting the basic set of 6502 processor commands
Proc65c02 | selecting an extended set of 65c02, 6501, and other processors.
Proc6501 | Same as Proc65c02.
Proc65816 | Select the 65816 processor.
CaseSensitive | Differentiating lowercase and uppercase letters in label names
CaseInsensitive | treated as equal lowercase and uppercase letters in label names
SwapBin | swap binary radix @ and modulo % operators - % now becomes binary radix and @ becomes modulo.

Syntax:

        .OPT option_name { , option_name }

Example:

        .OPT Proc65c02, CaseInsensitive
        .OPT Proc65816, CaseSensitive, SwapBin