Spim_smulator

By Abhilash Oommen Thomas (08MCS003) Elizabeth Isaac (08MCS010) Liz Joy (08MCS025) Prakhya K (08MCS036) Sujesh P Lal (08MCS054)

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SPIM  OBJECTIVE

To familiarize a new tool ‘SPIM’.  OUTCOME To understand the working of the Simulator and to code, load and execute assembly language programs

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 A software simulator that runs programs written for MIPS R2000/R3000

processors.  SPIM’s name is just MIPS spelled backwards  A self-contained system for running MIPS programs

 It is free and wide availability  simulators can provide a better environment for programming  Can detect more errors and provide more features than an actual computer  The MIPS architecture may be an example for a simple, clean RISC machine

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The MIPS Features  MIPS -Microprocessor without Interlocked Pipeline Stages  A RISC instruction set architecture (ISA) developed by MIPS Computer

Systems.  The early MIPS architectures were 32-bit (generally 32-bit wide registers and

data paths), while later versions were 64-bit.  One of the more interesting applications of the MIPS architecture is its use in

massive processor count supercomputers.

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The MIPS Features  The first commercial MIPS CPU model, the R2000, was announced in 1985  The R3000 succeeded the R2000 in 1988, adding 32 KB (soon increased to 64

KB) caches for instructions and data, along with cache coherency support for multiprocessor use  The R3000A was the processor used in the extremely successful Sony

PlayStation

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SPIM Installation  A freely-distributable program that simulates the operation

of the MIPS R2000/R3000 architecture  Unix  Linux  Macintosh OS  MS Windows

 Installation  System requirements  Free Download  

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http://www.cs.wisc.edu/larus/pcspim.zip http://www.cs.wisc.edu/larus/xspim.tar.gz

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User Interfaces  Unix, Linux, Mac OS  On Unix, Linux, Mac OS the SPIM program provides a simple terminal interface and a Windowing interface.  Microsoft Windows  On Microsoft Windows the SPIM program provides a console interface and a windows interface

Version Current version of SPIM is 7.4 (January 2009)

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Invoking PCSPIM for Windows

 After you have saved the source code, invoke

PCSPIM for Windows with  Start Menu->Programs->PCSpim forWindows  PCSPIM for Windows will load and a window that looks like this will appear:

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To load 'tutorial.s' for the first time, select File->Open... from the menu bar. A dialog will appear. Find and select D:\PCSpim tutorial\tutorial.s

 After clicking Open, the window will be populated

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SPIM simulator: registers PC HI

LO

generalgeneral -purpose registers 10/04/2009

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SPIM simulator: code address of instruction bit pattern of instruction

meaning of instruction’s bit pattern 10/04/2009

source code of program SCS VIT University

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SPIM simulator: data name of segment

address of first byte of row 10/04/2009

word-by wordby-word contents of memory (16 bytes per row) SCS VIT University

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Any error in your source code

 Click "no".  Go back and correct your source code using the text editor,  Then reload the file.

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 To run the program for the first time, select 'Simulator->Go'.  A pop-up window will appear asking for a starting address:

 Accept the default address

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 the entire program will have executed and terminated.  The console window will pop up, displaying the results.  The window looks like this:

Making changes and reloading  In order to debug your program, open a text editor with the 

  



source file and keep PCSPIM open as well. After making a change to the code, save the file, but keep the text editor open. Then, select 'Simulator->Clear Registers' from the menu. Then select 'Simulator->Reinitialize' from the menu. Finally, select 'Simulator->Reload (your path)\tutorial.s' from the menu. At this point test the program again.

Debugging Overview  If the file does not 'Read' (or assemble) correctly, the

simulator will print some error message to help you find the problem.  Even if the file 'Reads', it will not necessarily work properly in all cases.  PCSPIM provides the following debugging capabilities  Register display

 Breakpoints  Tracing

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Sample program #Sum.s .data no: result:

.asciiz "Enter the numbers to be added" .asciiz "Result"

.text main: la $a0,no li $v0,4 syscall li $v0,5 syscall move $s0,$v0 23

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li $v0,5 syscall move $s1,$v0 add $s3,$s1,$s0 la $a0,result li $v0,4 syscall move $a0,$s3 li $v0,1 syscall li $v0,10 syscall

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Video Presentation

 SPIM Demo

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References  www.cs.wisc.edu  www.google.com  www.mips.org  MIPS Programmers handbook by Erin Farquhar and Philip

Bunce  MARS: An education oriented MIPS assembly language simulator

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THANK YOU!!

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