Version 2.2 (R2008a) Fixed-Point Toolbox™ Software Release Notes

Version 2.2 (R2008a) Fixed-Point Toolbox Software

This table summarizes what's new in Version 2.2 (R2008a):

New features and changes introduced in this version are:

• Enhanced Memory Management

• New Rounding Functions for fi Objects

• New Bitwise Operator bitreplicate

• New Syntax for Bitwise Operator bitconcat

• ndgrid Function Support for Fixed-Point Inputs

• New fi Constructor Syntax

Enhanced Memory Management

The memory management of the fi object has been improved, and generating large multidimensional arrays should no longer hang the MATLAB environment.

When performing computations with fi objects from the MATLAB command line, the memory usage in bits for the fi variable a is on the order of

max(64, a.wordlength)*numberofelements(a)

The formula computes the number of bits used to store each element of an array, but does not include the overhead for each instance of the object. Similar to built-in mxArrays, there is additional overhead for each array. This overhead is used to store information about data type, fimath properties, and other settings that do not depend on the size of the array.

If you are concerned with memory usage, try compiling with emlmex or emlc. The compiled code uses the smallest C integer type that contains the word length of the variables. For example, if the fi variable a is 8-bit, then the compiled code will use approximately 8*numberofelements(a) bits of memory. The current maximum fixed-point word length in the Embedded MATLAB subset is 32 bits.

New Rounding Functions for fi Objects

Fixed-Point Toolbox software now provides the following fi object functions:

• ceil — Round toward positive infinity

• convergent — Round toward nearest integer with ties rounding to nearest even integer

• fix — Round toward zero

• floor — Round toward negative infinity

• nearest — Round toward nearest integer with ties rounding toward positive infinity

• round — Round toward nearest integer with ties rounding to nearest integer with greater absolute value

These functions are also supported by the Embedded MATLAB subset.

New Bitwise Operator bitreplicate

Fixed-Point Toolbox software now provides the bitreplicate function to replicate and concatenate the bits of a fi object.

bitreplicate is also supported by the Embedded MATLAB subset.

New Syntax for Bitwise Operator bitconcat

The Fixed-Point Toolbox function bitconcat has new syntax.

For more information see the bitconcat reference page.

ndgrid Function Support for Fixed-Point Inputs

Fixed-Point Toolbox software now provides support for the ndgrid function.

New fi Constructor Syntax

Fixed-Point Toolbox software has added a new syntax for the fi constructor. The syntax a = fi(V, F, T) is now defined, and is equivalent to the existing syntax a = fi(V, T, F).

See the fi function reference page for more information.

Version 2.3 (R2008b) Fixed-Point Toolbox Software

Version 2.1.1 (R2007b+) Fixed-Point Toolbox Software