number specifies the number of passes through the source code that the assembler should perform. An argument of ALL causes the assembler to perform the minimum number of passes necessary to optimize the size of the code. A count of 0, 1 or 2 causes the assembler to perform a standard two-pass assembly. Any other value causes the assembler to perform that number of passes (this may result in phase errors; it is best to specify ALL instead of number>2).
Note: It is rarely necessary to use pass=2, as the optimization time is minimal. The .contrl directive can be used to selectively turn off optimization for sections of code.