Function m20k_blocks 

pub fn m20k_blocks(depth: u64, width: u64) -> u64

The M20K blocks a memory of depth words of width bits takes: the fewest over the block’s simple-dual-port shapes (512 × 40, 1,024 × 20, 2,048 × 10), as many blocks side by side as its width needs and stacked as its depth does, the stack a power of two deep (the fitter decodes it by the address’s top bits).