hello
i'm having trouble using nested modules , in always blocks
how should i use a module in always block of a top module?
i want to use module(rf) to calculate some parameters module (alu) to execute then use module (rf) to save them
here's the entire code:
module registerfile(ar1,ar2,re,aw,w,we,clk,r1,r2 );
input re,we,clk;
input [2:0] ar1,ar2,aw;
input [3:0] w;
output reg [3:0] r1,r2;
reg [3:0] rf [0:7];
initial
begin
rf[0] = 4'b0000;
rf[1] = 4'b0000;
rf[2] = 4'b0000;
rf[3] = 4'b0000;
rf[4] = 4'b0000;
rf[5] = 4'b0000;
rf[6] = 4'b0000;
rf[7] = 4'b0000;
r1=4'b0;r2=4'b0;
end
always @(posedge clk)
if (we==1)
begin
rf[aw]=w;
end
always @(negedge clk)
if (re==1)
begin
r1=rf[ar1];r2=rf[ar2];
end
else
begin
r1=4'bx;r2=4'bx;
end
endmodule
module alu(a,b,op,out,c,n,z,v
);
input [3:0] a,b;
input [2:0] op;
output reg [3:0] out;
output reg z,n,v,c;
reg [2:0] x;
reg c3;
always @*
if (op[2:1]==2'b00)
begin
case (op[0])
1'b0: {c,out}=a+b;
1'b1: {c,out}=a-b;
endcase
{c3,x}={{a[2:0]}-{b[2:0]}};v=c^c3;z = out?1'b0:1'b1;n = {out[3]}?{1'b1}:{1'b0};
end
else
begin
case(op)
3'b010: out=a&b;
3'b011: out=a|b;
3'b100: out=a^b;
3'b101: out=~a;
3'b110: out=~(a&b);
3'b111: out=~(a|b);
default: out=4'b000;
endcase
z = out?{1'b0}:{1'b1};n = {out[3]}?{1'b1}:{1'b0};c=1'bx;v=1'bx;
end
endmodule
i can't use lower level modules in an always block placed in the top module
is there any solutions?
regards
Reza balaei
