System Verilog : Array Reduction & Array Ordering Methods

Array reduction methods can be applied to any unpacked array. The "with" clause can be used to specify the item to be used in the reduction.

sum() : returns the sum of all the array elements.

product() : returns the product of all the array elements

and() : returns the bit-wise AND(&) of all the array elements.

or() : returns the bit-wise OR(|) of all the array elements.

xor() : returns the logical XOR (^) of all the array elements.

module array_reduction;

int myarr [8:0]; logic larr [7:0]; int rsum,rprod,rxor,rnd,ror;

initial begin myarr = {6,3,1,2,4,8,5,7,9}; larr = {1,0,1,0,1,1,1,0};

rsum = myarr.sum(); $display("sum = %0d", rsum);

rprod = myarr.product(); $display("product = %0d", rprod);

rxor = myarr.xor(); $display("Xor = %0b", rxor);

rxor = larr.xor with ( item + 1); // 11 ^ 01 ^ 11 ^ 01 ^ 11 ^ 11 ^ 11 ^ 01 $display("Xor for larr - with clause = %0d", rxor);

rnd = larr.and(); $display("And = %0b", rnd);

ror = larr.or(); $display("Or = %0b", ror);

end endmodule /* ncsim> run sum = 45 product = 362880 Xor = 1 Xor for larr - with clause = 3 And = 0 Or = 1 */

In the above code, sum is the sum of all elements in the array. The execution of xor method has been done on myarr and larr. With larr with clause is used which will add 1 to each element and then do xor. Array Ordering Methods: Array ordering methods reorder the elements of any unpacked array (fixed or dynamically sized) except for associative arrays.

reverse() : It reverses the order of the elements in the array. The `with` clause cannot be specified with this.

sort() : It sorts the array in ascending order.

rsort() : It sorts the array in descending order.For both `sort` and `rsort`, the `with` clause (and its expression) is optional when the relational operators (<, >, ==) are defined for the array element type. If a `with` clause is specified, the relational operators(<, >, ==) shall be defined for the type of the expression.

shuffle() : It randomizes the order of the elements in the array. The `with` clause cannot be specified with this.

module array_order; int myarr [9:0];

initial begin myarr = {60,0,30,10,20,40,80,50,70,90}; display(myarr,"Array myarr");

myarr.reverse; display(myarr,"myarr.reverse() function");

myarr.sort(); display(myarr,"myarr.sort() function");

myarr.rsort; display(myarr,"myarr.rsort() function");

myarr.shuffle; display(myarr,"myarr.shuffle() function");

myarr.shuffle; display(myarr,"myarr.shuffle() function Again!!"); end

task display(int arr[9:0],string str); $display(str); for (int i=0; i<10;i++) $write(" %0d ",myarr[i]); $display("\n"); return; endtask endmodule /* ncsim> run Array myarr 90 70 50 80 40 20 10 30 0 60

myarr.reverse() function 60 0 30 10 20 40 80 50 70 90

myarr.sort() function 0 10 20 30 40 50 60 70 80 90

myarr.rsort() function 90 80 70 60 50 40 30 20 10 0

myarr.shuffle() function 0 10 30 40 20 90 60 70 80 50

myarr.shuffle() function Again!! 30 10 40 60 20 80 70 50 0 90 */