.OPT

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

Width3Width1771 Width3Width7441 Option name ImportanceWidth3Width1771 Width3Width7441
Width3Width1771 Width3Width7441 Proc6502 selecting the basic set of 6502 processor commandsWidth3Width1771 Width3Width7441
Proc65c02 selecting an extended set of 65c02, 6501, and other processors.Width3Width1771 Width3Width7441
Proc6501 Same as Proc65c02.Width3Width1771 Width3Width7441
CaseSensitive Differentiating lowercase and uppercase letters in label namesWidth3Width1771 Width3Width7441
Width3Width1771 Width3Width7441 CaseInsensitive treated as equal lowercase and uppercase letters in label namesWidth3Width1771 Width3Width7441

Syntax:

    .OPT option_name { , option_name }

Example:

    .OPT Proc65c02, CaseInsensitive