com.cmpware.cmp.links
Class CellBE_FIFO

java.lang.Object
  com.cmpware.cmp.Link
      com.cmpware.cmp.links.FIFO
          com.cmpware.cmp.links.CellBE_FIFO

All Implemented Interfaces:

MemoryMappedIOReader, MemoryMappedIOWriter

public class CellBE_FIFO
extends FIFO

This class is exactly like the typical FIFO, except that it does not stall when the FIFO is full. Instead it quietly overwrites the last entry. This implements the functionality of the PPU to SPU mailbox in the Cell BE.

Copyright (c) 2007 Cmpware, Inc. All Rights Reserved.

Author:

SAG

Field Summary

static java.lang.String

copyright Copyright string

Fields inherited from class com.cmpware.cmp.links.FIFO

DEFAULT_SIZE, fifo, head, mmioe, readAddr, readCount, readFlag, readStallCount, tail, writeAddr, writeCount, writeStallCount, writtenFlag

Constructor Summary

CellBE_FIFO(int size)
This constructor initializes the Cell BE FIFO.

Method Summary

void	write(int val) This method writes a word to the Memory Mapped IO.
void	writeCommit() All Memory Mapped IO writes are performed whenever data is available.

Methods inherited from class com.cmpware.cmp.links.FIFO

free, getReadAddress, getReadCount, getReadStallCount, getValue, getWriteAddress, getWriteCount, getWriteStallCount, isEmpty, isFull, isReadable, isWriteable, read, readCommit, reset, setBufferSize, setReadAddress, setWriteAddress, used

Methods inherited from class com.cmpware.cmp.Link

get

Methods inherited from class java.lang.Object

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

Field Detail

copyright

public static final java.lang.String copyright

Copyright string

See Also:

Constant Field Values

Constructor Detail

CellBE_FIFO

public CellBE_FIFO(int size)

This constructor initializes the Cell BE FIFO.

Parameters:

size - the size of the Cell BE FIFO.

Method Detail

write

public void write(int val)
           throws MemoryMappedIOException

Description copied from interface: MemoryMappedIOWriter

This method writes a word to the Memory Mapped IO.

Specified by:

write in interface MemoryMappedIOWriter

Overrides:

write in class FIFO

Parameters:

val - The value to write to the Memory Mapped IO.

Throws:

MemoryMappedIOException - - this method throws a MemoryMappedIOException if the write could not be completed on this cycle. This will typically cause a stall of the processor and a retry on the next cycle.

writeCommit

public void writeCommit()

Description copied from interface: MemoryMappedIOWriter

All Memory Mapped IO writes are performed whenever data is available. But because this is a multiprocessor simulation environment, it may not be proper to flag this communication resource as "free" until the end of the simulation cycle. This is necessary to preserve clock boundaries in multiprocessor simulation environments. This method should be called at the end of all activity in a simulation cycle and should tag the resource as free as necessary.

Specified by:

writeCommit in interface MemoryMappedIOWriter

Overrides:

writeCommit in class FIFO