CS 202, Fall 2007


Group Assignment #3: 50 Points.

Due Date: Tuesday, 12/18/07.


(15) 1.	The Simple language compiler is deficient in numerous ways.
	The final group assignment is to deliver an enhanced Simple
	compiler implementing as many new features as possible.  The 
	new features should offer improvements in one or more of the 
	following areas: (a) expression syntax, (b) error detection
	(c) user interface or (d) performance (SML code optimization).  
	The announcement of the release of the enhanced group products 
	will occur during in class presentations on Tuesday, 12/18.

	Each group will have approximately 30 minutes to describe why
	their compiler should be selected as the best implementation of
	the Simple language.  Each group should describe the unique
	features of the design, implementation and testing of their 
	version of the compiler in sufficient detail to convince the 
	audience that the compiler is not vaporware and really works.

	All members of the group should participate in the presentation
	in some manner.  The presentation should begin with a title
	slide listing the group name and members of the group.  Additional
	slides should discuss the features of the compiler.  Powerpoint
	is a good application to use for preparing slides.  Live
	demonstrations are a good way to sell a product to the audience,
	if the demo is well planned and works correctly.  The class 
	presentation will be graded on the clarity of information, 
	originality, organization, content, correctness and overall impact.

(35) 2.	The technical evaluation of the enhanced compiler will be scored 
	separately according to the point values listed below.  To receive
	full credit, each enhancement must be implemented, documented and 
	demonstrated to receive full credit.  All enhancements must be 
	implemented in a single version of the compiler and should not require
	modifications to the Simpletron SML instruction set.  Groups will 
	receive credit for only one version of the compiler.  All text, 
	source code and executable files must be handed in on a CD, 
	preferably together with the presentation files.  The enhanced 
	features and point values are as follows:**

	(5)  a. Modify the compiler to produce a source code listing of 
		the Simple program file followed by a listing of the 
		contents of the symbolTable array to cout.  The symbol table
		listing should be formatted into columns showing the
		location, type and value of each symbol in the table.

	(5)  b.	Modify the compiler to include comments in the SML code.
		Each numeric SML code should be followed by mnemonic
		for the code (READ, STORE, etc) along with the name of
		any operands from the symbol table.  For example, if
		the variable 'x' is stored in location 98, then the
		operation code 1098 would be followed by the comment 
		"READ x" on the same line of the SML code file.  Note 
		that this may require a modification to your simpletron 
		simulator in order to process the operation codes followed 
		by the mnemonic.  Note also that the compiler should 
		add a line containing -99999 to the end of the SML code
		file for compatibility with the simpletron input format.

	(5)  c.	Modify the functions which process the 'let' statement to 
		allow multidigit numeric constants in expressions.

	(5)  d.	Implement the modulus operator (%) for use in expressions.
		The precedence of the modulus operator is the same as 
		multiplication.  The definition of the modulus operation 
		for x%y is x-(x/y)*y, where '/' is integer division.

	(10) e.	Implement the exponentiation operator (^) for use in 
		expressions.  Exponentiation is right associative and has 
		higher precedence than multiplication.  Exponentiation of 
		x^y for integer operands is implemented in machine language 
		by multiplying x into the accumulator y times.  An exponent 
		of zero should produce a result of one.  Negative exponents 
		produce a result of zero.

	(10) f.	Add error detection and recovery to the Simple compiler so 
		that error messages are output when syntax errors are 
		encountered in a Simple program.  When an error is detected, 
		an informative message should be output and the compiler 
		should skip to the beginning of the next line and continue 
		compiling.  The following types of errors should be detected: 
		(i) Missing line number; (ii) Missing/misspelled keyword; 
		(iii) Missing '=' in 'let' statement; (iv) Missing/unrecognized 
		operator in 'let' expression.

	(10) g.	Modify the Simple compiler to provide an option for optimizing 
		the SML code produced by the compiler as described in Exercise 
		21.28.  Manually compare the nonoptimized code with the 
		optimized code for the Simple factorial program and calculate 
		the percentage reduction in memory use and in total 
		instructions executed.

	(10) h. Integrate the Simpletron simulator, the Simple language
		compiler and a text editor into a menu-driven Simple language
		development environment which provides a source editor, 
		compiler, debugger and execution of Simple language programs.

	(XC) i. Propose a different enhancement and receive extra credit
		points with the approval of the instructor.

	Extra credit may be earned for enhancements in accordance with the
	guidelines given in the project requirements.  Enhancements will
	typically receive a maximum of 5 points, but additional points may
	be awarded at the discretion of the instructor.  

      **For full credit, turn in fully commented program listings,
	including group name and the problem number(s), and the output
	from test runs exactly as produced by the program.