The Xilinx CMult block implements a gain operator, with output equal to the product of its input by a constant value. This value can be a MATLAB® expression that evaluates to a constant.
Block Parameters
The block parameters dialog box can be invoked by double-clicking the icon in your Simulink® model.
- Basic tab
-
Parameters specific to the Basic tab are as follows:
- Constant Type
-
- Fixed-point
- Use fixed-point data type.
- Floating-point
- Use floating-point data type. Can be a constant or an expression. If the constant cannot be expressed exactly in the specified fixed-point type, its value is rounded and saturated as needed.
- Fixed-point Precision
-
- Number of bits
- Specifies the bit location of the binary point of the constant, where bit zero is the least significant bit.
- Binary point
- Position of the binary point.
- Floating-point Precision
-
- Single
- Specifies single precision (32 bits)
- Double
- Specifies double precision (64 bits)
- Custom
- Activates the field below so you can specify the Exponent width and the Fraction width.
- Exponent width
- Specify the exponent width.
- Fraction width
- Specify the fraction width.
- Output tab
-
- Precision
- This parameter allows you to specify the output
precision for fixed-point arithmetic. Floating point arithmetic
output will always be Full precision.
- Full
- The block uses sufficient precision to represent the result without error.
- User Defined
- If you do not need full precision, this option allows you to specify a reduced number of total bits and/or fractional bits.
- Fixed-point Output Type
-
- Arithmetic type
-
- Signed (2’s comp)
- The output is a Signed (2’s complement) number.
- Unsigned
- The output is an Unsigned number.
- Fixed-point Precision
-
- Number of bits
- Specifies the bit location of the binary point of the output number, where bit zero is the least significant bit.
- Binary point
- Position of the binary point in the fixed-point output.
- Quantization
-
Refer to the section Overflow and Quantization.
- Overflow
-
Refer to the section Overflow and Quantization.
- Implementation tab
-
Parameters specific to the Implementation tab are as follows.
- Use behavioral HDL description (otherwise use core)
- When selected, Model Composer uses
behavioral HDL, otherwise it uses the Xilinx
LogiCORE™
™ Multiplier.
When this option is not selected (false) Model Composer
internally uses the behavioral HDL model for simulation if
any of the following conditions are true:
- The constant value is 0 (or is truncated to 0).
- The constant value is less than 0 and its bit width is 1.
- The bit width of the constant or the input is less than 1 or is greater than 64.
- The bit width of the input data is 1 and its data type is xlFix.
- Core Parameters
-
- Implement using
- Specifies whether to use distributed RAM or block RAM.
- Test for optimum pipelining
- Checks if the Latency provided is at least equal to the optimum pipeline length supported for the given configuration of the block. Latency values that pass this test imply that the core produced is optimized for speed.
Other parameters used by this block are explained in the topic Common Options in Block Parameter Dialog Boxes.