The synthesis guy just came back and said that the logic+memories area is looking to be 72 mm2. We only have 58 mm2 of space in the middle of our huge 8.5 x 8.5 mm die. We are 24% oversized!!!
We need to shave at least 14 mm2 (72 - 58).
We have 16 instances of 8192x32 SP RAM at 1.57mm2 = ~25mm2.
We have 32 instances of 512x32 DP RAM at 0.292mm2 = ~9.3mm2.
Those RAMs total to ~34mm2.
This means our current logic is 72 - 34 = 38 mm2. That's over 3x what Prop2-Hot was with 8 cogs! The smart pins are contributing to this bloat.
Each smart pin is 1/9th the logic of a cog, so 64 of them are equivalent to 64/9 = 7 cogs. The CORDIC is equivalent to 2 cogs. So, we have 16 + 7 + 2 = 25 cogs' equivalent of logic here. This means a cog's worth of logic is about 1.5 mm2 (38 / 25).
If we cut the cogs from 16 down to 8, we save 8 * (1.5 mm2 for logic + 2 * 0.292 mm2 for 512x32 DP RAMs) = 16.7 mm2. That gets us where we need to be, by 2.7 mm2. That 2.7 mm2 will hopefully be enough spare room.
I told him to reduce the cogs from 16 to 8. That also halves the main RAM, for now, but I believe they have a 16kx32 instance we could use to keep the hub RAM at 512KB. We'll see what he comes back with.