Hardware/Broadway

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PPC redirects here. For the SDK library, see PPC (SDK)

The Broadway is the main processor on the Wii, and runs games. Games have the entire processor to themselves; IOS runs on the Starlet.

The Broadway does not have a boot ROM; instead, code is booted from EXI memory that the Starlet initializes. The Starlet is also responsible for loading the main code to be run, as this initial code simply resets the MSR and jumps to 0x3400.

Specifications

  • IBM 'Broadway' 90 nm based on IBM's PowerPC architecture.
  • Runs at a speed of 729 MHz. Maximum Bandwidth is 1.9 GB/s.
  • Bus to main memory: 243 MHz, 64 bits (maximum bandwidth: 1.9 GB/s)
  • 32 KB 8-way set-associative L1 instruction cache
  • 32 KB 8-way set-associative L1 data cache (can set up 16-kilobyte data scratch pad)
  • Superscalar microprocessor with six execution units (floating-point unit, branching unit, system register unit, load/store unit, two integer units)
  • DMA unit (15-entry DMA request queue) used by 16-kilobyte data scratch pad
  • Write-gather buffer for writing graphics command lists to the graphics chip
  • Onboard 256-kilobyte 2-way set-associative L2 integrated cache
  • Two, 32-bit integer units (IU)
  • One floating point unit (FPU) (supports single precision (32-bit) and double precision (64-bit))
  • The FPU supports paired single floating point (FP/PS)
  • The FPU supports paired single multiply add (ps_madd). Most FP/PS instructions can be issued in each cycle and completed in three cycles.
  • Fixed-point to floating-point conversion can be performed at the same time as FPU register load and store, with no loss in performance.
  • The branch unit supports static branch prediction and dynamic branch prediction.
  • When an instruction is stalled on data, the next instruction can be issued and executed. All instructions maintain program logic and will complete in the correct program order.
  • Supports three L2 cache fetch modes: 32-Byte, 64-Byte, and 128-Byte.
  • Supports these bus pipeline depth levels: level 2, level 3, and level 4.

Reference Information: Broadway is upward compatible with Nintendo GameCube’s CPU (Gekko).