--- Quote Start ---
the code you have posted is verilog and you dont show how randh and address are declared in verilog.
data <= walls_rand( to_integer( unsigned(randh(1 downto 0) & address(3 downto 0) ) );
--- Quote End ---
whole verilog code as follow
module wall_generator(
input clk,
input [63:0]rand,
input hold,
input [5:0]address,
output reg [5:0]data
);
reg [63:0]randh;
reg [5:0]walls_rand[0:63];
reg [5:0]walls_alt[0:63];
reg [5:0]walls_maze[0:127];
always @(posedge clk) begin
if(!hold) begin
randh <= rand;
end
end
always @* begin
case(address[5:4])
2'd0: begin
data <= walls_rand[{randh[1:0],address[3:0]}];
end
2'd1: begin
data <= walls_alt[{randh[3:2],address[3:0]}];
end
2'd2: begin
data <= walls_rand[{randh[5:4],address[3:0]}];
end
2'd3: begin
data <= walls_maze[{randh[8:6],address[3:0]}];
end
endcase
end
