javax.realtime

Class RawMemoryFloatAccess

java.lang.Object

javax.realtime.RawMemoryAccess

javax.realtime.RawMemoryFloatAccess

public class RawMemoryFloatAccess
extends RawMemoryAccess

Jamaica Real-Time Specification for Java class RawMemoryFloatAccess

This class enables the low-level access of a range of physical memory as a sequence of bytes. This class permits the development of device drivers using memory-mapped I/O, flash memory, battery-backed RAM, etc.

The memory can be accessed as primitive types byte, short, int, long, float, double, or as arrays of these primitive types. No non-primitive types (Java references or Java objects) can be stored in this memory since this would undermine Java's inherent type safety for references and objects.

The byte ordering on accesses to the memory depends on the current setting of RealtimeSystem.BYTE_ORDER.

Field Summary

Fields inherited from class javax.realtime.RawMemoryAccess

byteSwapEnabled_

Constructor Summary

Constructors

Constructor and Description
RawMemoryFloatAccess(Object type, long size) Constructor to create an instance of RawMemoryFloatAccess for the given parameters and make this memory accessible.
RawMemoryFloatAccess(Object type, long base, long size) Constructor to create an instance of RawMemoryFloatAccess for the given parameters and make this memory accessible.

Method Summary

Modifier and Type	Method and Description
double	getDouble(long offset) getDouble reads a double from the given offset.
void	getDoubles(long offset, double[] doubles, int low, int number) getDoubles reads a number of doubles from the given offset.
float	getFloat(long offset) getFloat reads a float from the given offset.
void	getFloats(long offset, float[] floats, int low, int number) getFloats reads a number of floats from the given offset.
void	setDouble(long offset, double value) setDouble writes a double to the given offset.
void	setDoubles(long offset, double[] doubles, int low, int number) setDoubles writes a number of doubles to the given offset.
void	setFloat(long offset, float value) setFloat writes a float to the given offset.
void	setFloats(long offset, float[] floats, int low, int number) setFloats writes a number of floats to the given offset.

Methods inherited from class javax.realtime.RawMemoryAccess

getByte, getBytes, getInt, getInts, getLong, getLongs, getMappedAddress, getShort, getShorts, map, map, map, setByte, setBytes, setInt, setInts, setLong, setLongs, setShort, setShorts, swapBytes, swapBytes, swapBytes, unmap

Methods inherited from class java.lang.Object

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

Constructor Detail

RawMemoryFloatAccess

public RawMemoryFloatAccess(Object type,
                            long size)
                     throws SecurityException,
                            OffsetOutOfBoundsException,
                            SizeOutOfBoundsException,
                            UnsupportedPhysicalMemoryException,
                            MemoryTypeConflictException,
                            OutOfMemoryError

Constructor to create an instance of RawMemoryFloatAccess for the given parameters and make this memory accessible.

The base address will be chosen freely by the implementation.

Throws:

SecurityException - if the application is not allowed to access physical memory or memory of the specified type.

SizeOutOfBoundsException - iff size is negative or base plus size extends into an illegal memory range.

OffsetOutOfBoundsException - iff base is invalid.

UnsupportedPhysicalMemoryException - if the specified memory type is not supported.

MemoryTypeConflictException - if the memory at the specified base address is incompatible with the attributes specified in the type parameter.

OutOfMemoryError - if there is no memory of the specified type available.

Parameters:

type - The type of the memory (e.g., PhysicalMemoryManager.DMA, etc). This may be an array of types if several type attributes are required. type may be null if any memory type is acceptable.

size - the size of the range.

RawMemoryFloatAccess

public RawMemoryFloatAccess(Object type,
                            long base,
                            long size)
                     throws SecurityException,
                            OffsetOutOfBoundsException,
                            SizeOutOfBoundsException,
                            UnsupportedPhysicalMemoryException,
                            MemoryTypeConflictException,
                            OutOfMemoryError

Constructor to create an instance of RawMemoryFloatAccess for the given parameters and make this memory accessible.

JamaicaVM currently does not support virtual memory, so no mapping of the specified memory will be performed by this constructor.

Throws:

SecurityException - if the application is not allowed to access the specified range of memory or memory type.

SizeOutOfBoundsException - iff size is negative or base plus size extends into an illegal memory range.

OffsetOutOfBoundsException - iff base is invalid.

UnsupportedPhysicalMemoryException - if the specified memory type is not supported.

MemoryTypeConflictException - if the memory at the specified base address is incompatible with the attributes specified in the type parameter.

OutOfMemoryError - if there is no memory of the specified type available.

Parameters:

type - The type of the memory (e.g., PhysicalMemoryManager.DMA, etc). This may be an array of types if several type attributes are required. type may be null if any memory type is acceptable.

base - the base address of the range.

size - the size of the range.

Method Detail

getDouble

public double getDouble(long offset)
                 throws OffsetOutOfBoundsException,
                        SizeOutOfBoundsException

getDouble reads a double from the given offset. The read may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

Parameters:

offset - the offset of the first byte from the beginning of this memory range.

Returns:

the double read.

getDoubles

public void getDoubles(long offset,
                       double[] doubles,
                       int low,
                       int number)
                throws OffsetOutOfBoundsException,
                       SizeOutOfBoundsException

getDoubles reads a number of doubles from the given offset. The reads may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

ArrayIndexOutOfBoundsException - if low < 0 or (low + number) >= doubles.length or (low + number) < 0.

IllegalArgumentException - if doubles is null or number < 0.

Parameters:

offset - the offset of the doubles from the beginning of this memory range.

doubles - (out!) an array to hold the read doubles.

low - offset in doubles array where the first value is stored.

number - number of doubles to be read.

getFloat

public float getFloat(long offset)
               throws OffsetOutOfBoundsException,
                      SizeOutOfBoundsException

getFloat reads a float from the given offset. If naturally aligned, the float is read in an atomic read operation. If not aligned, the read may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

Parameters:

offset - the offset of the first byte from the beginning of this memory range.

Returns:

the float read.

getFloats

public void getFloats(long offset,
                      float[] floats,
                      int low,
                      int number)
               throws OffsetOutOfBoundsException,
                      SizeOutOfBoundsException

getFloats reads a number of floats from the given offset. If naturally aligned, each float is read in an atomic read operation. If not aligned, the read may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

ArrayIndexOutOfBoundsException - if low < 0 or (low + number) >= floats.length or (low + number) < 0.

IllegalArgumentException - if floats is null or number < 0.

Parameters:

offset - the offset of the floats from the beginning of this memory range.

floats - (out!) an array to hold the read floats.

low - offset in floats array where the first value is stored.

number - number of floats to be read.

setFloat

public void setFloat(long offset,
                     float value)
              throws OffsetOutOfBoundsException,
                     SizeOutOfBoundsException

setFloat writes a float to the given offset. The write may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

Parameters:

offset - the offset of the first byte from the beginning of this memory range.

value - the float to be written.

setFloats

public void setFloats(long offset,
                      float[] floats,
                      int low,
                      int number)
               throws OffsetOutOfBoundsException,
                      SizeOutOfBoundsException

setFloats writes a number of floats to the given offset. The writes may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

ArrayIndexOutOfBoundsException - if low < 0 or (low + number) >= floats.length or (low + number) < 0.

IllegalArgumentException - if floats is null or number < 0.

Parameters:

offset - the offset of the floats from the beginning of this memory range.

floats - an array that holds the floats to be written.

low - offset in floats array where the first value to be written will be taken from.

number - number of floats to be written.

setDouble

public void setDouble(long offset,
                      double value)
               throws OffsetOutOfBoundsException,
                      SizeOutOfBoundsException

setDouble writes a double to the given offset. The write may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

Parameters:

offset - the offset of the first byte from the beginning of this memory range.

value - the double to be written.

setDoubles

public void setDoubles(long offset,
                       double[] doubles,
                       int low,
                       int number)
                throws OffsetOutOfBoundsException,
                       SizeOutOfBoundsException

setDoubles writes a number of doubles to the given offset. The writes may be not atomic.

Throws:

SizeOutOfBoundsException - if this is not mapped or offset specifies an address in an invalid address range.

OffsetOutOfBoundsException - if offset is negative or greater than the size of the raw memory area.

ArrayIndexOutOfBoundsException - if low < 0 or (low + number) >= doubles.length or (low + number) < 0.

IllegalArgumentException - if doubles is null or number < 0.

Parameters:

offset - the offset of the doubles from the beginning of this memory range.

doubles - an array that holds the doubles to be written.

low - offset in doubles array where the first value to be written will be taken from.

number - number of doubles to be written.