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Please Help!!!! I am receiving the error "error (suppressible): (vsim-3601) Iteration limit 5000 reached at time 6 us". My code is as given below . I am trying to make ALU multiplier.

QRobi
Beginner
1,496 Views

module mrl(a,b,res,rs);

input [3:0]a;

input [3:0]b;

 

output [5:0]res;

output rs;

 

reg overflow;

reg [2:0]r;

reg [1:0]sum;

reg [2:0]cb;

reg [1:0]carry;

integer ii;

always @(a[1] || a[2] || a[3] || a[0] || b[0] ||b[1]||b[2]||b[3]) 

begin

sum[0]=1'b1;

sum[1]=1'b1;

end

 

 

 

always @(*)

begin

cb[0]=b[0];

cb[1]=b[1];

cb[2]=b[2];

for(ii=0; ii<3; ii=ii+1)

begin

if(cb[0]==1'b1)

begin

r[0] = a[0]^r[0]^~cb[0]; 

carry[0] = (a[0]&r[0])|(r[0]&~cb[0])|(~cb[0]&a[0]);

r[1] = a[1]^r[1]^carry[0]; 

carry[1] = (a[1]&r[1])|(r[1]&carry[0])|(carry[0]&a[1]);

r[2] = a[2]^r[2]^carry[1]; 

overflow = (a[2]&r[2])|(r[2]&carry[1])|(carry[1]&a[2]);

end

cb[2]=cb[1];

cb[1]=cb[0];

cb[0]=r[2];

r[2]=r[1];

r[1]=r[0];

r[0]=overflow;

overflow=1'b0;

end

end

assign rs=a[3]^b[3];

assign res[0]=r[0];

assign res[1]=r[1];

assign res[2]=r[2];

assign res[3]=cb[0];

assign res[4]=cb[1];

assign res[5]=cb[2];

 

endmodule

 

 

 

 

 

 

0 Kudos
2 Replies
Vicky1
Employee
1,151 Views

Hi,

By error it seems that your simulator stuck in an infinite loop, it might be because of forever loop or there are number of processes triggering to each other without reaching to it`s stability.

check (or provide) testbench with delay statement for ending simulation at particular interval.

Regards,

Vicky

Vicky1
Employee
1,151 Views

Hi,

May I know any update?

Thanks,

Vicky

Reply