This can be implemented in the following method. Here your requirement is to invoke the task1 in the first clock cycle and task2 in the upcoming cycles. You can model to call it at the same time or in the different clock cycles or after some specific time period etc. You can model it as per your requirement. This depends on how you invoke the tasks in your code. Please find below example for task calling another task.
#Pcalc function list code
Above code just calculate AWIDTH by using const-function.Ġ -> Parameter Values DWIDTH= 16 DEPTH= 512 AWIDTH= 10 $monitor($time," -> Parameter Values DWIDTH=%d DEPTH=%d AWIDTH=%d",DWIDTH,DEPTH,AWIDTH) In the below example it calculates AWIDTH by using constant function.įunction integer Clogb2(input integer depth) įor (Clogb2 = 0 depth > 0 Clogb2 = Clogb2 + 1) $monitor($time," -> Factorial of Num %d = %d, ",num,fact) Ĭonstant function can be used to instead of constants. Following is a well known example for automatic function.įunction automatic integer Factorial_calc_Func įactorial_calc_Func = Factorial_calc_Func(n-1) * n But by using automatic keyword, all function declarations are allocated dynamically for each call and operate on independent variable space. If normal functions are called recursively, the results are non-deterministic because both calls operate on the same variable space. A simple code, but always used in the designs.
#Pcalc function list how to
Tmpout muxin = %b, msel = %b, mout = %b",muxin,msel,mout) īelow example shows how to calculate parity using function. As it cannot handle timing control statement, delays etc and executes in 0 simulation time, it can only enable another function and not task. Also note that it cannot have output or inout arguments. Function will return a single value and it usually uses for calculations. There is at least one input argument is needed to use function. Function can be used if there is no requirement for specifying delays, timing control constructs or events. Functionįunctions are declared using function & endfuncion keywords. To avoid this problem a keyword automatic is added to make the task reentrant. If a task is called concurrently from different places in the code these task calls will operate on the same task variables. Simulation complete via $finish(1) at time 120 NS + 0 $monitor($time," ->muxin = %b, msel = %b, mout = %b",muxin,msel,mout) MUX4X1_Using_TASK mux_task(mout,muxin,msel) It does not return value like function instead it can pass multiple value through output or inout arguments. As it executes in non-zero simulation time, it can enable other task and functions. It may have zero or more than input,output or inout argument. Task must be used if delay, event or timing control constructs are required in the procedure. Task is declared using task & endtask keyword. There are some more differences, which we will be discussed in this sesssion. The highlighting difference between task and function is that, only task can handle event, delay or timing control statements and function executes in zero simulation time. Both task and function are called from always or initial block and contain only behavioural statements.ĭefinition of task and function must be in a module. In this way, common procedures need to be written only once and can execute from different places. Task and Function are used to break up large procedures into smaller ones which helps to make life easier for developing and maintaining Verilog code.
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