The Xilinx Expression block performs a bitwise logical expression.
The
expression is specified with operators described in the table below. The number of
input ports is inferred from the expression. The input port labels are identified
from the expression, and the block is subsequently labeled accordingly. For example,
the expression: ~((a1 | a2) & (b1 ^ b2)) results
in the following block with 4 input ports labeled 'a1', 'a2', 'b1', and 'b2'.
The expression is parsed and an equivalent statement is written in VHDL (or Verilog). Shown below, in decreasing order of precedence, are the operators that can be used in the Expression block.
| Operator | Symbol |
|---|---|
| Precedence | () |
| NOT | ~ |
| AND | & |
| OR | | |
| XOR | ^ |
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.
- Expression
- Bitwise logical expression.
- Align Binary Point
- Specifies that the block must align binary points automatically. If not selected, all inputs must have the same binary point position.
Other parameters used by this block are explained in the topic Common Options in Block Parameter Dialog Boxes.