Apr 12, 2010 · It's best practice to only set values of regs in the same always block. eg: always @( * ) begin // combo logic block if( some_condition ) begin icache_ram_rw = 1'b0; end else begin icache_ram_rw = something_else; end

May 10, 2017 · Verilog-2001 style is preferred (SystemVerilog's always_comb is even better). always @* Non-blocking ( <= ) should be used to assign synchronous logic (flops and latches).

There are two ways to declare inputs to a function: sum = a + b; end endfunction function [7:0] sum (input [7:0] a, b); begin . The function definition will implicitly create an internal variable of the same name as that of the function. Hence it is illegal to declare another variable of the same name inside the scope of the function.

Function Output . The output from a function is assigned to the function name. A Verilog function has only one output, which can be a vector. For multiple outputs from a function, use the concatenation operation to bundle several values into one return value. This single return value can then be unbundled by the caller.

Aug 13, 2024 · A function can return up to 1 value. The width of the return value for the function is set by the range specifier in the declaration. This must be a constant width - e.g. a literal width, a parameter value, etc. Returning a value is achieved by assigning a value to the function name.

Mar 19, 2019 · When you declare something as input or output, how do you know if you have to also declare it as a reg or a wire? reg and wire specify how the object will be assigned and are therefore only meaningful for outputs.

Feb 21, 2022 · Furthermore the output a module cannot be connected directly to a reg type variable. Instead, to connect multiple things together in Verilog, you use wire (net data type). For example. wire [3:0] addResult; fullAdder add(..., addResult); ... 4'b0010: result = addResult; The same goes for carryOut.

Sep 13, 2018 · When using an output argument, you must declare a variable to receive the value. bit test; function void my_function (output bit value); value = ... endfunction ... my_function (test); if (test) ... If all you want to do is test the value, it is much easier to use the return value.

Nov 2, 2020 · In verilog, a function is a subprogram which takes one or more input values, performs some calculation and returns an output value. We use functions to implement small portions of code which we want to use in multiple places in our design.

Feb 3, 2024 · Input arguments get copied by value upon entry task/function and output arguments get copied upon exit. Inouts get copied both upon entry and exit. There are only two main use cases where you would want to use a ref argument.