Gate: a Chipmonk subroutineThe Chipmonk subroutine called GATE will layout a VLSI gate-array like layout from a textspecification of the gates involved and their inputs. Inputs (and outputs) are specified by their signal (ornode) names. A node name can be any identifier (a string of digits and/or letters, up to 100 characters).Case is ignored.The circuit specification is read from a text file. In the text file, each gate is represented by one"line" (a line is terminated by or simicolon). The format of a gate-specifying line is: : ... is the identifier for the node connected to the Output of the gate. isoptional; if it is present it consists of a decimal number enclosed in parentheses, and specifies thegate parameters (pullup size) for this one gate. If there is no , the default is used.See "Gate Parameters" below.The gates which can be used are equivalent to "and-or-invert" gates with an arbitrary number of "NOR"inputs, each of which comes from an "AND" (which may have one or more inputs). Each"AND" may have arbitrarily many inputs (keep it within reason, or the gate widths will get outof hand). defines one "AND" and there are as many of them on the line as there are "NOR"s in thegate. The consists of a single node name for a one-input "AND"; or a series of Nnode names, enclosed in square brackets, for an N-input "AND".Node names and s are seperated by a , which is any collection of spaces and commas.Naturally the collection must be non-null when two identifiers are being seperated. is exactly one carriage-return or semicolon.Other types of lines:A comment line is one whose first non- character is a minus (-). Everything from the minus tothe is ignored.The default gate parameter index starts out as 1, but may be changed by a line consisting of a alone. The default is unchanged by a gate line which specifies the for that gate.Examples:An inverter:Out1:in1A two-input Nor:Out2:in1,in2A three-input Nand, using gate parameters # 3:out(3):[in4 in5 in6 ]A 2-2-3 and-or-invert:out4 : [in10,in11][in20 in21] [ in30 , in31 in32 ]A comment:- this is a commentTwo inverters and a comment:o1:i1;o2:i2;-these inverters are sillySetting a new default:(2)Notes:Blank lines are ignored. Extra spaces and commas are ignored. Comments must be first (non blankor comma) thing on a line, so if you wish to put a comment after a gate spec, without a carriage returna'p)\qA [:58 Y/; X2)UM Ty])RhrP PWsqNNaMORK I\HOF,2E  Bs q#4AR:$?> = &sq/<S 9s q- 7ft)51qE 3)1y.7 /E -zt +iu )Ws 'Fu%5s #$u.!s us2 u rs us& u#s t) q10 VU : CuY)2between, precede the - with a ;.Parameter Spec Index:This number specifies a set of parameters used in buiding the gate. The default is 1, which is a set ofparameters with a 2-by-2 pullup, and Nor pull-downs which are 8-by-2. (AND pull-downs are wider bythe number of AND inputs). Other indexes which are currently defined are: 2 has 4-by-2 pullups and 16-by-2 pull-downs. 3 has 6-by-2 pullups and 24-by-2 pull-downs. 4 has 2-by-4 pullups and 4-by-2 pull-downs. 5 is defined for test purposes but will not work correctly.Running GATE:To run GATE (as with any of the subroutines) you type ";" (semicolon). Chipmonkwill prompt to ask for the subroutine name. You type "GATE". After a wait, GATE will ask for the filename. If it hits a problem with the input file, it will put up the message: "File Syntax Error". Yourespond with which will abort the GATE run and get you back to Chipmonk. If it has no problemwith the file, it creates the circuit as a single cell (sith sub-cells) and puts it at the MARK. When it hasfinished, it will almost always put up the error message: "Problem running subroutine/ Pages left over".You can ignore this message (type ); it is due to a bug in chipmonk which will be fixed in the nextrelease.Rather than asking a lot of questions, try it.Nfv bq _t)]nqe [Z ZfP XU W^C Tt )RqG Q+M OL N#"A L` KB& I52 H E. ECu"t TIMESROMAN TIMESROMAN GACHA TIMESROMAN  TIMESROMAN  TIMESROMANGACHA j/ gate.brPetitOctober 16, 1981 12:34 AM