PowerPoint PresentationOverviewLanguage ContinuumInterpretation vs TranslationInterpretationTranslationSlide 7Interpretation vs. Translation?Steps to Starting a ProgramCompilerUpcoming CalendarAdministrivia…Midterm in 1 week!Administrivia…Other stuffWhere Are We Now?AssemblerAssembler Directives (p. A-51 to A-53)Pseudoinstruction ReplacementProducing Machine Language (1/2)Producing Machine Language (2/2)Symbol TableRelocation TableObject File FormatPeer InstructionPeer Instruction AnswerAnd in conclusion…CS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (1)Garcia, Fall 2004 © UCBLecturer PSOE Dan Garciawww.cs.berkeley.edu/~ddgarciainst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 18 – Running a Program Iaka Compiling, Assembling, Linking, Loading (CALL) 2004-10-11Finally, Tivo for the radio! Griffin Technologies releasedtheir new “radioSHARK” for $70 that allows you to pause live radio and “timeshift”your radio shows. Easily download them easily to your iPod…cool! griffintechnology.com/products/radioshark/CS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (2)Garcia, Fall 2004 © UCBOverview•Interpretation vs Translation•Translating C Programs•Compiler•Assembler•Linker (next time)•Loader (next time)•An Example (next time)CS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (3)Garcia, Fall 2004 © UCBLanguage Continuum•In general, we interpret a high level language if efficiency is not critical or translated to a lower level language to improve performanceEasy to programInefficient to interpretEfficientDifficult to programSchemeJavaC++ C Assembly machine languageJava bytecodeCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (4)Garcia, Fall 2004 © UCBInterpretation vs Translation•How do we run a program written in a source language?•Interpreter: Directly executes a program in the source language•Translator: Converts a program from the source language to an equivalent program in another language•For example, consider a Scheme program foo.scmCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (5)Garcia, Fall 2004 © UCBInterpretationScheme program: foo.scmScheme InterpreterCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (6)Garcia, Fall 2004 © UCBTranslationScheme program: foo.scmHardwareScheme CompilerExecutable(mach lang pgm): a.out°Scheme Compiler is a translator from Scheme to machine language.CS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (7)Garcia, Fall 2004 © UCBInterpretation•Any good reason to interpret machine language in software?•SPIM – useful for learning / debugging•Apple Macintosh conversion•Switched from Motorola 680x0 instruction architecture to PowerPC.•Could require all programs to be re-translated from high level language•Instead, let executables contain old and/or new machine code, interpret old code in software if necessaryCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (8)Garcia, Fall 2004 © UCBInterpretation vs. Translation?•Easier to write interpreter•Interpreter closer to high-level, so gives better error messages (e.g., SPIM)•Translator reaction: add extra information to help debugging (line numbers, names)•Interpreter slower (10x?) but code is smaller (1.5X to 2X?)•Interpreter provides instruction set independence: run on any machine•Apple switched to PowerPC. Instead of retranslating all SW, let executables contain old and/or new machine code, interpret old code in software if necessaryCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (9)Garcia, Fall 2004 © UCBSteps to Starting a ProgramC program: foo.cCompilerAssembly program: foo.sAssemblerLinkerExecutable(mach lang pgm): a.outLoaderMemoryObject(mach lang module): foo.olib.oCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (10)Garcia, Fall 2004 © UCBCompiler•Input: High-Level Language Code (e.g., C, Java such as foo.c)•Output: Assembly Language Code(e.g., foo.s for MIPS)•Note: Output m ay contain pseudoinstructions•Pseudoinstructions: instructions that assembler understands but not in machine (last lecture) For example:• mov $s1,$s2 or $s1,$s2,$zeroCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (11)Garcia, Fall 2004 © UCBUpcoming CalendarWeek # Mon Wed Thurs Lab Fri#7This weekRunning Program IRunning Program IIRunning ProgramCaches#8Midterm weekCachesMidterm @ 7pm1 PimintelCaches Caches Caches Midterm grades outCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (12)Garcia, Fall 2004 © UCBAdministrivia…Midterm in 1 week!•2004-10-18 @ 7-10pm in 1 Piminitel•Covers labs,hw,proj,lec up to Caches•Last sem midterm + answers on www•Bring…•NO backpacks, cells, calculators, pagers, PDAs•2 Pens (we’ll provide write-in exam booklets)•One handwritten (both sides) 8.5”x11” paper•One green sheet (corrections below to bugs from “Core Instruction Set”)1) Opcode wrong for Load Word. It should say 23hex, not 0 / 23hex. 2) sll and srl should shift values in R[rt], not R[rs]i.e. sll/srl: R[rd] = R[rt] << shamtCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (13)Garcia, Fall 2004 © UCBAdministrivia…Other stuf•Bug in Friday’s slides (slide 19)•WAS: ori $at,$zero,lower 16 bits•SHOULD BE: ori $at,$at,lower 16 bits•Grades in for Homework XX, Proj YY•You have one week to request official ‘regrade’ from reader – specify reason. •Reader will then regrade entire HW/Proj (grade may go down). In exceptional cases, can appeal to TA to intervene.•If no appeal generated within a week, grade frozen, no way to change after that. (Regrade could still be pending, tho)CS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (14)Garcia, Fall 2004 © UCBWhere Are We Now?C program: foo.cAssembly program: foo.sExecutable(mach lang pgm): a.outCompilerAssemblerLinkerLoaderMemoryObject(mach lang module): foo.olib.oCS 61C L18 Running a Program aka Compiling, Assembling, Loading, Linking (CALL) I (15)Garcia, Fall 2004 ©
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