Hi All,
I was referring to following quote from SV LRM: 13.3 Tasks
An array can be specified as a formal argument to a task. For example:
// the resultant declaration of b is input [3:0][7:0] b[3:0]
task mytask4(input [3:0][7:0] a, b[3:0], output [3:0][7:0] y[1:0]);
...
endtask
(Q1) I am aware that all 3 arguments would be of logic type and that b inherits input direction, but why does b inherit the packed dimensions ( [3:0][7:0] ) from a?
SV LRM: 13.3 Functions states ::
To indicate the return type of a function, its declaration can either include an
explicit data_type_or_void or use an implicit syntax that indicates only the
ranges of the packed dimensions and, optionally, the signedness.
When the implicit syntax is used, the return type is the same as if the implicit
syntax had been immediately preceded by the logic keyword. In particular, the
implicit syntax can be empty, in which case the return type is a logic scalar.
So, function [15:0] f1(); // f1() has default return type as logic [15:0]
(Q2) Where would the keyword signed be written? After or before the packed dimensions?
function [15:0] signed f1_sign1();
// or
function signed [15:0] f1_sign2();
Same section of the LRM states
Once a direction is given, subsequent formals default to the same direction.
The const and static qualifiers on the ref direction are included in this default.
I get the first line that directions are sticky. If the 2nd argument is missing a direction, it will inherit it from 1st argument
(Q3) What does the 2nd line ( The const and static …. ) mean?
(Q4) Does the LRM mention regarding inheriting packed dimensions from previous arguments?
(a) In below function declaration, would ‘b’ inherit the packed dimensions [3:0][7:0] ?
// Is 'b' implicitly input logic [3:0][7:0] b [3:0] ?
function [3:0][7:0] myfunc4(input [3:0][7:0] a, b[3:0]);
....
endfunction
(b) In below function declaration, does y inherit packed dimension [7:0] ?
// Is 'y' of type input logic [7:0] y ?
function [15:0] myfunc1 (input [7:0] x,y);
myfunc1 = x * y - 1; // return value assigned to function name
endfunction
Thanks