.ifndef

Starts a conditional assembly block, making assembly conditional on a symbol not being defined.

  .ifndef symbol statement-group

Parameters

symbol

Any valid symbol.

statement-group

Any valid assembly statements.

Remarks

If previous code does not include a definition for symbol, the assembler processes the statements of the block. If there is a definition for symbol, the assembler skips the statements of the block.

Each .ifndef directive must have a matching .endif directive.