COP 4600 Project obj2Spring 2012

Instructor:Dr. Euripides Montagne

TA:Yuan Li

University of Central Florida

Task: simulate booting the OS

Load and execute the boot program

Input file: boot.dat

− (1) segment table info

− (2) instructions

Procedures:

− (1) Load the boot program from boot.dat

− (2) Save the segment table info and instructions to memory

− (3) Interpret and execute instructions of the program

What you need to do:

− Implement 11 functions described in obj2.c

Functions to implement Functions include

– void boot();– void Get_Instr(int prog_id, struct instr_type* instruction);– void Cpu();– void Exec_Program(struct state_type* state);– int Memory_Unit();– void Set_MAR(struct addr_type* addr);– int Fetch(struct instr_type* instruction);– int Read(struct instr_type* instruction);– int Write(struct instr_type* instruction);– void Display_pgm(segment_type* seg_table, int seg_num,

pcb_type* pcb)

Step (1): Load the boot program from boot.dat

An example of boot.datDetailed

description

Step (2): Initialize memory and save the boot data to memory

Save segment information to segment table (Mem_Map)– struct segment_type * Mem_Map– See osdef.h for prototype of struct segment_type– See externs.h for declaration of Mem_Map– See simulator.c for initilization of Mem_Map

Save instructions to main memory (Mem)

– Struct instr_type* Mem

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4, 0x01, 0

4, 0x02, 4

8, 0x03, 8

1, 0x04, 16

SIO 75

DISK 2000

SKIP 0

JUMP [2,0]

0

1

2

3

Mem_Map

SKIP 1

JUMP [3,0]

SKIP 0

JUMP [2,6]

SIO 400

PRNT 150

WIO 500

REQ [0,1]

WIO 0

REQ [2,1]

SKIP 0

END 20

JUMP [1,0]

Mem

01

23

4

56

7

8

910

1112

1314

15

16

Segment table

Memory

Memory Structure

#Inst, Acc, Base

Instruction Set

Instruction format: opcode oprand opcode_type: SIO, WIO, END, Device, REQ,

JUMP, SKIP SIO n

− CPU burst for n cycles and start IO

WIO n− CPU burst for n cycles and wait for IO

END n− CPU burst for n cycles and end program

Instruction Set

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Instruction set Device n

− Always follows SIO

− n is the bytes transferred (used to calculate time needed)

− Device can be DISK, PRNT……

⧫ SIO 75

⧫ DISK 2000

REQ [segment, offset]

− Always follows WIO

⧫ PRNT 150

⧫ WIO 0

⧫ REQ [2,1]

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Instruction Set

JUMP [seg, off]− Jump to memory [seg, off]

SKIP n− Skip the next instruction for n times

⧫ SKIP 1⧫ JUMP [3,0]⧫ SIO 400

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Program Skeleton

In simulator.c

Main()

{

……

Boot(); // Load boot.dat into memory, print out memory layout

……

while( new_events != NULL ) {

……

Interrupt(); // take out one event, print it out (consume one event)

……

Exec_Program( ….); // Simulate a cpu cycle (generate one event)

……

}

}

Boot() reads in the file boot.dat to load the kernel and initialize Mem_Map and Mem– Get_Instr() // Read one instruction from a program– Display_pgm() // Display memory layout

Exec_Program() simulates a context switch that places a user program in execution

– CPU() // Simulate one CPU cycle

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Description of functions

Next

Function: Get_Instr()

viod Get_Instr( int prog_id, struct instr_type* instruction )

Read an instruction from file Prog_Files[prog_id]

Load the instruction to struct instr_type* instruction

Process different types of instructions according to their specific format

Back

Function: Display_pgm()

void Display_pgm( segment_type* seg_table, int seg_num, pcb_type* pcb )

Display a single segment to output file. seg_table: the segment table seg_num: the index of the segment within

seg_table to display (seg_table[seg_num]) pcb: process control block that the segment

table belongs to

See intro.doc at eustis.eecs.ucf.edu for detailed format of output

Back

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Back

Function: CPU()

CPU() simulates the Central processing Unit Fetches the next instruction from memory

Fetch() Interprets the instruction

SIO, WIO, END, SKIP, JUMP Creates a further event and insert it to the event

queue if the instruction is SIO, WIO, END

Functions used by CPU()

void Set_MAR(struct addr_type* addr )

Set Memory Address Register (MAR) to the given address and prepare the next memory location for the next Fetch(), read() or Write() operation

MAR = [segment, offset], logic address int Memory_Unit( )

Simulate the Memory Management Unit (MMU) that translates the logic address in the Memory Address Register (MAR) to a real physical address.

Address = base of segment in Mem_Map + offset in MAR int Fetch(struct instr_type* instruction)

Get the instruction from memory, Mem[Memory_Unit()] and save to struct instr_type* instruction

Back

Summary obj2

The simulator (the main() function of simulator.c) calls Boot() to load programs from boot.dat

Boot() first initializes the memory, then call Get_Instr() repeatedly to read

instructions from boot.dat, and finally call Display_pgm() to print out the

memory layout

Summary of obj2

After Boot() is done, the simulator calls Exec_Program() to simulate a context switch

Then Exec_Program() calls CPU() to simulate Central Processing Unit

CPU() calls Set_MAR() to set the memory address register (MAR) to the value of CPU.state.pc

CPU() calls Fetch() to the next instruction from memory

Summary of obj2

Fetch() Calls Memory_Unit() to convert the logic

address in MAR to real physical address Then fetch the instruction in

Mem[Memory_Unit()] Finally, return to CPU()

CPU() then processes the instruction accordingly The simulator terminates when all the events are

done

Make copyfiles

– You do not need to execute this command if your obj2.c already exists.

– This command can copy *.h and *.c from Dr. Montagne's home folder to yours.

– Be careful, if you have already modified any objx.c file, please back up your *.c files before you run this comment. Otherwise, your code will be lost.

Make data2files

Modify obj2.c

– Reuse obj1.c, you may need to modify obj1.c

Make sim, then run “sim”

Make compare OBJ=2– If error happens, manually check data2.out and ossim.out, see what is wrong

– You should expect “Done. Looks OK to me...”

Make submit– You should see “If you dont get any error message,submit is successful.”

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Compile, test and submit your code