QtSpim Tutorial

QtSpimTutorialContents

1. Installation2. Usage3. Overview4. FirstProgram

Installation

WewillbeusingSPIM,aMIPSsimulator,inordertolearnassemblyprogramming.ThecurrentversionofSPIMis"QtSPIM",akaSPIMusingtheQtcrossplatformapplicationGUIframework:

InstalltheQtframeworkthatSPIMrequires:

unix>sudoaptgetinstallqt4devtoolsqt4doclibqt4help

DownloadaprepackagedversionofSPIMforLinuxthatusestheQtGUIframework:(Ifyouarerunninganolder32bitLinuxinstallation,change64to32below)

unix>wgethttp://sourceforge.net/projects/spimsimulator/files/qtspim_9.1.12_linux64.deb

InstalltheQtSPIMpackage:

unix>sudodpkgiqtspim_9.1.12_linux64.deb

Usage

TolaunchQtSPIM:

unix>qtspim&

Overview

AfterlaunchingQtSPIM,themainwindowshouldappearasshownbelow.

http://qt.nokia.com/http://qt.nokia.com/http://spimsimulator.sourceforge.net/

Therearethreeprimarysectionscontainedwithinthiswindow:TheRegisterpanel,Memorypanel,andMessagespanel.

RegisterPanel

TheRegisterpanel(shownbelow)showsthecontentsofalltheMIPSregisters.Therearetwotabsinthispanel:oneforthefloatingpointregistersandonefortheintegerregisters.Theintegerregistersincludegeneralpurposeregisters(R1R31),alongwithspecialpurposeregisterssuchastheProgramCounter(PC).

MemoryPanel

TheMemorypanelhastwotabs:DataandText.TheTexttabshowsthecontentsoftheProgrammemoryspace.Fromlefttoright,thisincludes:

1. Thememoryaddressofaninstructioninhexadecimal(showninbrackets)2. Thecontentsofthatmemoryaddressinhexadecimal.Inbinaryform,thisistheactualMIPS

instructionthattheprocessorruns!3. The"humanreadable"assemblylanguageinstructionusingthehardwareregisternumbers

(showninbold).4. Theassemblylanguageprogramyouwroteusingsymbolicregisternamesandmemory

addresssymbols(showninitalics)

TheDatatabshowsthecontentsoftheDatamemoryspace.Thisincludesthevariablesandarraydatayoucreate,alongwiththestackcontent.

MessagesPanel

TheMessagespaneldisplaysmessagesfromQtSPIMtotheuser.

FirstProgram

AvarietyofMIPSexampleprogramsareavailabletoyou.Startwiththefirstprogramexample1.asmbydownloadingittoyourcomputer.

LoadyourfirstprogrambyselectingFile>ReinitializeandLoadFile.(RecallthatthenewUbuntu"Unity"GUIdoesn'tshowthetopofscreenmenubaruntilyoumouseoverit).Thisclearstheregisterspaceandresetsthesimulator.(Otherwise,youcouldloadandrunseveralprogramsinarowonthesamemachinestate.)

YoucanscrolldownintheTextpanetoseethattheassemblycodehasbeenloadedintoProgrammemoryspace.Inthiscase,thefirstinstructionisatmemorylocation0x00400024.(Whydoesn'titstartatmemoryaddresszero?Theprogramstartswiththefunctionmain(),butthereissomecode

http://ecs-network.serv.pacific.edu/ecpe-170/tutorials/example1.asm/viewhttp://ecs-network.serv.pacific.edu/ecpe-170/tutorials/mips-example-programs

thatrunsbeforemain).

Nowthattheprogramhasbeenloaded,youcanrunasimulationoftheassemblyinstructions.Youhavethreechoices:

1. Runtheprogramfrombeginningtoend(viathe"play"Run/ContinuebuttonorF5).Thisisusefulforseeingthefinaloutputoftheprogram.

2. Stepthroughtheprogramonelineatatime(viathe"123"SingleStepbuttonorF10).Thisisusefultoseehoweachassemblyinstructionaffectsthemachinestate(i.e.memoryandregistervalues).

3. Runtheprogramuntilyoureachabreakpoint(whichcanbesetbyrightclickingonanylineintheMemorypanel.

Stepthroughthecompleteprogram,figureoutwhatitdoes,andmakesureyouunderstandhowtheQtSPIMenvironmentworks.