6 ms·

Modern OoO CPUs solve the need for more physical registers than logic registers with renaming. https://docs.boom-core.org/en/latest/sections/rename-stage.html

• Taniwha 4y ago
  Yes VRoom! with renaming has as many registers as it has commitQ entries plus the architectural ones. So 64/32 + 31 (integer) + 32 (fp) + 32 (vector)
  • phkahler 4y ago
    The idea was to have as many simple ALUs as registers. Results are kept in the ALU/register. All reads are essentially result forwarding. For example a simple RV32I requires 2 read ports and one write port on each register. If we use 2 R/W ports and put an ALU on each register, you reduce from 3 to 2 busses and can also do operations 2 at a time when an instruction clobbers one of its inputs. Or an ALU op along with a load/store.