What is exact difference between program and module. When i compiled below program. Program main; module ma; endmodule. ERROR:: a module can only be declared at the compilation unit top level, or within a module SystemVerilog. And have seen that program cannot contain always block. Verilog Blocking and Non-blocking. Verilog supports blocking and non-blocking assignments statements within the always block with their different behaviors. The blocking assignment is similar to software assignment statements found in most popular programming languages. The Program construct provides a race-free interaction between the design and the testbench, all elements declared within the program block will get executed in the Reactive region. Non-blocking assignments within the module are scheduled in the active region, initial blocks within program blocks are scheduled in the Reactive region.
- Program Block Vs Module Systemverilog
- Verilog Vs Systemverilog
- For Loop In Systemverilog
- Systemverilog Spec
(30)Without using randomize method or rand,generate an array of unique values?
Ans:-
(32)What is the difference between byte and bit [7:0]?
Ans:-
byte is signed whereas bit [7:0] is unsigned.
(33)What is the difference between program block and module?
Ans:-
Program block is newly added in SystemVerilog. It serves these purposes
Ans:-
(32)What is the difference between byte and bit [7:0]?
Ans:-
byte is signed whereas bit [7:0] is unsigned.
(33)What is the difference between program block and module?
Ans:-
Program block is newly added in SystemVerilog. It serves these purposes
Module Instantiation: Refer to modules instantiated in other modules. Program 1 shows examples of input/output ports for a simple module instantiation. Module Declaration: Refer to the actual Verilog code written for a module. Program 2 shows examples of inputs/outputs within a module declaration. Notice that each input and output. Besides, Verilog has a single always block to implement combinational and sequential logic while SystemVerilog has alwayscomb, alwaysff and alwayslatch procedural blocks. While Verilog is based on a hierarchy of modules, SystemVerilog is based on classes. Additionally, Verilog uses module level testbench while.
- It separates testbench from DUT
- It helps in ensuring that testbench doesn't have any race condition with DUT
- It provides an entry point for execution of testbench
- It provides syntactic context (via program ... endprogram) that specifies scheduling in the Reactive Region.
Having said this the major difference between module and program blocks are
- Program blocks can't have always block inside them, modules can have.
- Program blocks can't contain UDP, modules, or other instance of program block inside them. Modules don't have any such restrictions.
- Inside a program block, program variable can only be assigned using blocking assignment and non-program variables can only be assigned using non-blocking assignments. No such restrictions on module
- Program blocks get executed in the re-active region of scheduling queue, module blocks get executed in the active region
- A program can call a task or function in modules or other programs. But a module can not call a task or function in a program.
Program Block Vs Module Systemverilog
More details:-- http://www.project-veripage.com/program_blocks_1.php and few more next/next !!!
- Section 16, SystemVerilog LRM 3.1a ... It's worth the effort reading line-by-line (and between the lines if you can :) ).
Verilog Vs Systemverilog
Ans:-
Modports are part of Interface. Modports are used for specifing the direction of the signals with respect to various modules the interface connects to.
Please refer section 19.4 of SV LRM for more details
For Loop In Systemverilog
11. Explain about the virtual task and methods .Ans:-
Systemverilog Spec
See http://www.testbench.in/CL_07_POLYMORPHISM.html PROCEDURAL BLOCKS
Final:
Verilog procedural statements are in initial or always blocks, tasks, or functions. SystemVerilog adds a final block that executes at the end of simulation.SystemVerilog final blocks execute in an arbitrary but deterministic sequential order. This is possible because final blocks are limited to the legal set of statements allowed for functions.
EXAMPLE :
module fini;
initial
#100$finish;
final
$display(' END OF SIMULATION at %d ',$time);
endmodule
RESULTS:
END OF SIMULATION at 100
Jump Statements:
SystemVerilog has statements to control the loop statements.
break : to go out of loop as C
continue : skip to end of loop as C
return expression : exit from a function
return : exit from a task or void function
Event Control:
Any change in a variable or net can be detected using the @ event control, as in Verilog. If the expression evaluates to a result of more than 1 bit, a change on any of the bits of the result (including an x to z change) shall trigger the event control.
SystemVerilog adds an iff qualifier to the @ event control.
EXAMPLE:
module latch (outputlogic[31:0] y,input[31:0] a,input enable);
always@(a iff enable 1)
y <= a;//latch is in transparent mode
endmodule
Always:
In an always block that is used to model combinational logic, forgetting an else leads to an unintended latch. To avoid this mistake, SystemVerilog adds specialized always_comb and always_latch blocks, which indicate design intent to simulation, synthesis, and formal verification tools. SystemVerilog also adds an always_ff block to indicate sequential logic.
EXAMPLE:
always_comb
a = b & c;
always_latch
if(ck) q <= d;
always_ff@(posedge clock iff reset 0orposedge reset)
r1 <= reset ?0: r2 +1;
Final:
Verilog procedural statements are in initial or always blocks, tasks, or functions. SystemVerilog adds a final block that executes at the end of simulation.SystemVerilog final blocks execute in an arbitrary but deterministic sequential order. This is possible because final blocks are limited to the legal set of statements allowed for functions.
EXAMPLE :
module fini;
initial
#100$finish;
final
$display(' END OF SIMULATION at %d ',$time);
endmodule
RESULTS:
END OF SIMULATION at 100
Jump Statements:
SystemVerilog has statements to control the loop statements.
break : to go out of loop as C
continue : skip to end of loop as C
return expression : exit from a function
return : exit from a task or void function
Event Control:
Any change in a variable or net can be detected using the @ event control, as in Verilog. If the expression evaluates to a result of more than 1 bit, a change on any of the bits of the result (including an x to z change) shall trigger the event control.
SystemVerilog adds an iff qualifier to the @ event control.
EXAMPLE:
module latch (outputlogic[31:0] y,input[31:0] a,input enable);
always@(a iff enable 1)
y <= a;//latch is in transparent mode
endmodule
Always:
In an always block that is used to model combinational logic, forgetting an else leads to an unintended latch. To avoid this mistake, SystemVerilog adds specialized always_comb and always_latch blocks, which indicate design intent to simulation, synthesis, and formal verification tools. SystemVerilog also adds an always_ff block to indicate sequential logic.
EXAMPLE:
always_comb
a = b & c;
always_latch
if(ck) q <= d;
always_ff@(posedge clock iff reset 0orposedge reset)
r1 <= reset ?0: r2 +1;