Instruction memory uses LC

[harrysarson]

I believe that in https://github.com/physical-computation/RV32I_iCE40/blob/master/verilog/instruction_mem.v#L13:

assign out = instruction_memory[addr >> 2];

Is not getting synthesised as BRAM. To fix this I think this line may need to be moved into an always block.

[rjlv2]

The instruction memory is written as combinational logic (and is not clocked, BRAM requires a clock). The limited amount of BRAM available is used in the general purpose registers and data memory.

Making instruction memory work using BRAM can be a future improvement.