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In addition to the description on page 13 of AI Memo 116A LAP has the following features: Current Assembly Location Reference, Assembly Time Arithmetic, Constants, Multiple Entry Routines, and Defined Machine Operations in LAP. The atom "*" has a SYM value during assembly an integer which is the current cell address being assembled into. Thus (JRST O *) is a well known infinite loop equivalent to A (JRST O A). When LAP encounters a non-atomic argument in the position normally occupied but the address part of an instruction, and it is not one of the recognizable forms (QUOTE atom) (E function) of (C constant), then the assembly time calculates of the list of members are summed and this is the quantity assigned as address. Thus (JRST O (* 1)) is a do-little instruction roughly equivalent to TRA * +1 in FAP. |
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