WWW.TESTBENCH.IN - Vera Constructs

Tutorials

Specman E
Interview Questions

OPERATORS PART 3
Shift :

# <<               left shift
# >>               right shift

EXAMPLE :Shift
program main {
   reg [3:0] a_1,a_0;
   a_1     =  4'b1100 ;
   a_0     =  4'b0011 ;

printf(" << by 1  a_1  is %b a_0 is %b \n ",a_1 << 1,a_0 << 1);
printf(" >> by 2  a_1  is %b a_0 is %b \n ",a_1 >> 2,a_0 >> 2);
printf(" >> by 2  a_1  is %b a_0 is %b \n ",a_1 >> 2,a_0 >> 2);
printf(" << by 1  a_1  is %b a_0 is %b \n ",a_1 << 1,a_0 << 1);

}
RESULTS

<< by 1  a_1  is 1000 a_0 is 0110
  >> by 2  a_1  is 0011 a_0 is 0000
  >> by 2  a_1  is 0011 a_0 is 0000
  << by 1  a_1  is 1000 a_0 is 0110

Bit-Reverse :

><               bit reverse

EXAMPLE : Bit-reverse
program main {
    reg [3:0] a_1,a_0;
    a_1     =  4'b1100 ;

    printf(" >< a_1  is %b  \n ",><a_1 );
}
RESULTS

>< a_1  is 0011

Increment And Decrement :

++ increment

--               decrement

EXAMPLE : Increment and Decrement
program main {
    integer a_1,a_0;
    a_1  = 20 ;
    a_0  = 20 ;
    a_1 ++ ;
    a_0 -- ;
    printf (" a_1 is %d a_0 is %d ",a_1,a_0);
}
RESULTS

a_1 is 21 a_0 is 19

Conditional :

?:               conditional

EXAMPLE : Conditional
program main {
    integer i,j,sub;
    for (i=0; i<3; i++)
    for (j=3; j>0; j--){
        sub = (i>j) ? i-j : j-i;
        printf("i = %0d\t j = %0d\tsub = %0d\n", i,j,sub);
    }
}
RESULTS

i = 0    j = 3  sub = 3
i = 0    j = 2  sub = 2
i = 0    j = 1  sub = 1
i = 1    j = 3  sub = 2
i = 1    j = 2  sub = 1
i = 1    j = 1  sub = 0
i = 2    j = 3  sub = 1
i = 2    j = 2  sub = 0
i = 2    j = 1  sub = 1

Set

in !in dist

EXAMPLE : Set
program main {
    integer i;
    i = 20;
    if( i in {10,20,30})
        printf(" I is in 10 20 30 ");
}
RESULTS

I is in 10 20 30

Replication :

  { number {}}

EXAMPLE : Replication
program main {
    reg [5:0]  i;
    i = { 3{2'b10}};
    printf(" I is %b ",i);
}

RESULTS

I is 101010

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