Hi Veli. I think that should be synthesizable. I have written similar code where the LHS is a dynamic index to an array. I have not additionally used a fixed width slice, but I think since the width is a fixed parameter, it shouldn’t be a problem. A dynamic index and a dynamic width, I think would be a problem.

// input_byte is a 8 bit logic input
// input_index is 3 bit logic input
localparam int unsigned FIXED_WIDTH = 8;
logic[63:0] data_array;
data_array[input_index *FIXED_WIDTH +: FIXED_WIDTH] <= input_byte;

Hi Yunsung. I just ran a test to prove it to myself. You’re right! Thanks for correcting this major mistake!

Haha hard to find time with work and a kid. Wish I had time to write more.

Hi Venkat. The array definition makes extracting one dimension easier than the other, so you should be careful about how you define the array. To accomplish what you want to do, you can write a loop to extract each element that you need and assign that element to a new 256-entry single dimensional array.

Hi Agnes. If you create an unpacked struct (typedef struct, without the packed keyword), then you can have an unpacked array like the wr_pending_fifo_mem in the structure. However, Design Compiler will not synthesize an unpacked struct. What are you trying to achieve? Putting a FIFO into a struct seems to be a bit of a strange construct.

Can I include an unpacked array in a struct or an interface? For example, I like to pass an FIFO and some other info of a module to another to snooping. can I have a struct like this:
typedef struct packed {
logic [5:0] dev_sel;
logic [31:0] wr_pending_fifo_dv;
logic [31:0] wr_pending_fifo_mem [128];
} dev_wr_fifo_s;

Would an interface have the same elements?

Thanks
Agnes

Thank you Jason for your venerated inputs.