Class MMU

java.lang.Object
  |
  +--MMU

public class MMU

extends java.lang.Object

The MMU class represents the memory management unit hardware in a computer system.

Field Summary

static int	FRAME_COUNT MMU.FRAME_COUNT is the number of page frames in physical memory.
static int	MEMORY_SIZE MMU.MEMORY_SIZE is the number of bytes in physical memory.
static int	NONE MMU.NONE is the int code for disallowing all access.
static int	OFFSET_BITS MMU.OFFSET_BITS is the number of page offset bits in a memory address.
static int	PAGE_SIZE MMU.PAGE_SIZE is the size of a memory page.
static int	READ MMU.READ is the int code for read access.
static int	RO MMU.RO is the int code for allowing read-only access.
static int	RW MMU.RW is the int code for allowing read-write access.
static int	WRITE MMU.WRITE is the int code for write access.

Method Summary

static int	getAdjustedSize(int sz) MMU.getAdjustedSize(sz) returns the smallest integer multiple of MMU.PAGE_SIZE that is greater than or equal to sz.
static Page	getPage(int frameNum) MMU.getPage(frameNum) returns the contents of the frame numbered frameNum.
static void	putPage(int frameNum, Page pg) MMU.putPage(frameNum, pg) puts the contents of pg into the frame numbered frameNum.
static void	read(int addr) MMU.read(addr) simulates a memory read at address addr.
static void	setPTBR(PageTable pt) MMU.setPTBR(pt) sets the page table base register to point to pt.
static void	write(int addr) MMU.write(addr) simulates a memory write at address addr.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

OFFSET_BITS

public static final int OFFSET_BITS

MMU.OFFSET_BITS is the number of page offset bits in a memory address.

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Constant Field Values

PAGE_SIZE

public static final int PAGE_SIZE

MMU.PAGE_SIZE is the size of a memory page.

This definition should not be changed. To change the page size, change the OFFSET_BITS definition.

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Constant Field Values

MEMORY_SIZE

public static final int MEMORY_SIZE

MMU.MEMORY_SIZE is the number of bytes in physical memory.

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Constant Field Values

FRAME_COUNT

public static final int FRAME_COUNT

MMU.FRAME_COUNT is the number of page frames in physical memory.

This definition should not be changed. To change the number of pages, change the MEMORY_SIZE definition or the PAGE_SIZE definition.

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Constant Field Values

READ

public static final int READ

MMU.READ is the int code for read access.

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Constant Field Values

WRITE

public static final int WRITE

MMU.WRITE is the int code for write access.

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Constant Field Values

NONE

public static final int NONE

MMU.NONE is the int code for disallowing all access.

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Constant Field Values

RO

public static final int RO

MMU.RO is the int code for allowing read-only access.

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Constant Field Values

RW

public static final int RW

MMU.RW is the int code for allowing read-write access.

See Also:

Constant Field Values

Method Detail

getAdjustedSize

public static int getAdjustedSize(int sz)

MMU.getAdjustedSize(sz) returns the smallest integer multiple of MMU.PAGE_SIZE that is greater than or equal to sz. string.

setPTBR

public static void setPTBR(PageTable pt)

MMU.setPTBR(pt) sets the page table base register to point to pt.

read

public static void read(int addr)

MMU.read(addr) simulates a memory read at address addr.

write

public static void write(int addr)

MMU.write(addr) simulates a memory write at address addr.

putPage

public static void putPage(int frameNum,
                           Page pg)

MMU.putPage(frameNum, pg) puts the contents of pg into the frame numbered frameNum.

getPage

public static Page getPage(int frameNum)

MMU.getPage(frameNum) returns the contents of the frame numbered frameNum.