comp150 Spring 2003 Introduction to Computer Science Michael Goldwasser Loyola University Chicago Handout Exam3 Info Tuesday 22 April 2003 Exam 3 Information The final exam for this course will be on Thursday 1 May 2003 from 2 30 4 30pm This exam is closed book and no calculating devices of any type will be allowed However the following aides are allowed Included with this packet is a copy of the relevant help files associated with the Super Simple CPU and Palgo commands You will be allowed to bring these prepared notes into the exam with you In addition to the notes provided by us you may add your own personal notes onto both the front and back of this one sheet of paper for use during the exam When the exam is over staple this sheet to the rest of your exam The format of the midterm will be as follows There will be 14 questions available on the exam Each student must choose to solve exactly 12 of the 14 questions Students are free to read all of the questions and make attempts before deciding which 12 to select However the student must explicitly mark which 12 problems are to be graded if this is not clear we will assume that the first 12 problems are to be graded The potential coverage of material will be as follows Approximately 50 of the questions will cover new material that is topics which were introduced since the last exam Specifically it will included coverage of lectures from Thursday 20 Mar 2003 through Thursday 29 Apr 2003 as well as the associated readings and homeworks for those topics please see the class schedule for exact coverage The remainder of the exam will be cumulative revisiting major topics from the first two thirds of the course As a sample we will provide you with the second midterm which was used last semester in this course as well as with the solutions to that exam Keep in mind that the exact coverage of topics varies from semester to semester so this sample is meant mostly as an example of the style of the questions as opposed to the precise content of the questions MORE ABOUT THE SUPER SIMPLE CPU INSTRUCTIONS 1111 STP this stops the computer no more fetch decode execute cycles until you reset 0001 ADD fetch a number from memory and add it to the contents of the accumulator replacing the value value in the accumulator E g 0001 000000001111 get the value at memory location 15 and add that to accumulator 0010 SUB just like ADD only subtract 0011 LOD fetch a number from memory and store it into the accumulator replacing its old value E g 0011 000000001111 get the value at memory location 15 and store that value into the accumulator 0100 LDI load immediate the value to be put into the accumulator is the rightmost 12 bits of the instruction do not go to memory like LOD 0100 000000001111 store the value 15 into the accumulator 0101 STO store the accumulator s value into memory at the indicated location PALGO COMMANDS YOU CAN USE examples var expression assign an expression s value to a variable var input input a string var input number input a number print expression pen down pen up color red color 158 207 96 goto 5 6 down 8 up 8 left 8 right 8 draw draw 5 6 wait 500 numcells 40 clear STRUCTURES YOU CAN USE repeat 20 times end E g E g 0101 000000001111 store the accumulator s value into memory location 15 0110 INP ask the user for one number and store that into the accumulator 0111 OUT copy the value in the accumulator to the output area 1000 JMP jump to the instruction at the indicated memory address 1000 000000001111 put the value 15 into the PC which will cause the next instruction to be taken from location 15 of memory 1001 JNG jump to the instruction at the indicated memory location if the accumulator s value is negative otherwise just add 1 to the PC while i 10 end if n 5 then end if n 5 then else end for i 0 to 10 end E g E g 1001 000000001111 put the value 15 into the PC if accumulator 0 otherwise go to the next instruction 1010 JZR jump to the instruction at the indicated memory location if the accumulator s value is zero otherwise just add 1 to the PC E g 1010 000000001111 put the value 15 into the PC if accumulator 0 otherwise go to the next instruction define square n end