Hollywood (graphics chip)

Hollywood

ATI "Hollywood" GPU within the Wii console
Designed by	ATI
Fabrication process	90 nm or 65 nm CMOS

The Hollywood chipset, a key component of Nintendo's Wii video game console, is a system on a chip (SoC) that integrates a graphics processing unit (GPU), I/O interfaces, and audio capabilities. Designed by ATI (later acquired by AMD), it was manufactured using a 90 nm or 65 nm CMOS process (depending on the hardware revision), ^[1] similar to the Wii's central processing unit, Broadway .

While specific details about Hollywood remain relatively scarce, it's believed to be based on the GameCube's Flipper GPU, operating at a 50% higher clock speed of 243 MHz. ^[2] However, these technical specifications have never been officially confirmed.

The Hollywood is a multi-chip module (MCM), with three dies under the cover in the initial Hollywood-A revision chip. The first of these three dies, codenamed Vegas, controls the I/O functions, RAM access, the Audio DSP, and the actual GPU with its embedded DRAM, and measures 8 × 9 mm. The other, codenamed Napa, holds 24 MB of "internal" 1T-SRAM and measures 13.5 × 7 mm. ^[3] A third, tiny die contains EEPROM. The Hollywood-1 revision, codenamed Bollywood, was fabricated on a 65 nm node and merges Napa and Vegas into a single die, resulting in a two-die MCM. ^[4]

Hardware capabilities

• 243 MHz graphics chip
• 3 MB embedded GPU memory (eDRAM)
  • 2 MB dedicated to Z-buffer and framebuffer
  • 1 MB texture cache
• 24 MB 1T-SRAM @ 486 MHz (3.9 GB/s) directly accessible for textures and other video data
• Fixed function pipeline (no support for programmable vertex or pixel shaders in hardware)
• Texture Environment Unit (TEV) - capable of combining up to 8 textures in up to 16 stages or "passes"
• ~30 GB/s internal bandwidth^
• ~18 million polygons/second^
• 972Mpixels/sec peak pixel fillrate

Note: ^ denotes speculation: using confirmed ATI GameCube data x 1.5, a crude but likely accurate way of calculating the Wii's results based on clock speeds and identical architecture.

Texture Environment Unit

The Texture Environment Unit (TEV) is a unique piece of hardware exclusive to the GameCube and Wii. The Wii inherited the TEV from Flipper, and the TEV is—to use an analogy from Factor 5 director Julian Eggebrecht—"like an elaborate switchboard that makes the wildest combinations of textures and materials possible." ^[5]

The TEV pipeline combines up to 8 textures in up to 16 stages at once. Each stage can apply a multitude of functions to the texture. This was frequently used to simulate pixel shader effects such as bump-mapping, or to perform effects such as cel shading. On the GameCube, Factor 5's Star Wars: Rogue Squadron II used the TEV for the targeting computer effect and the simulated volumetric fog. ^[5] In another scenario, Wave Race: Blue Storm used the TEV notably for water distortion (such as refraction) and other water effects.^{[ citation needed ]} The Wii's TEV unit and TEV capabilities are no different from the GameCube's, excluding indirect performance advantages from the faster clock speeds.^{[ citation needed ]}

Starlet

Hollywood contains an ARM926EJ-S core, which has been unofficially nicknamed Starlet. ^{[6] [7]} This embedded microprocessor runs an undocumented operating system called IOS and performs many of the Wii's I/O functions, including controlling the wireless functionality, USB, the SD card interface, the optical disc drive, the internal NAND flash storage, WiiConnect24 when the console is in standby mode, and other miscellaneous functions. ^[8] The Starlet acts as the security controller of the console, performing various cryptography functions; Starlet is designed to remain secure even if the Broadway is compromised. ^[8] Hollywood includes hardware implementations of AES ^[9] and SHA-1 ^[10] to speed up Starlet's security functionality. Communication between the Starlet and the Broadway is accomplished via an IPC mechanism. ^[8] Starlet has complete control over Broadway; the former can reboot the latter and supply it with code to execute at any time. ^[7]

References

1. "Wiiの概要 (Wii本体)" (in Japanese). Nintendo. Archived from the original on 2006-06-15. Retrieved 2007-01-03.
2. "IGN: Revolution's Horsepower". IGN. 2006-03-29. Archived from the original on 2011-05-22. Retrieved 2006-12-23.
3. Eda, Hiroki (2006-11-27). "PS3 VS Wii, Comparisons of Core LSI Chip Areas". Tech-On!. Archived from the original on 2007-01-03.
4. "Guide - De-Lidding the Wii chips". BitBuilt - Giving Life to Old Consoles. Retrieved 2021-05-17.
5. Eggebrecht, Julian (November 14, 2001). "PGC interviews Factor 5's Julian Eggebrecht: Technically speaking" (Interview). Interviewed by Nintendo World Report (Planet GameCube). Archived from the original on April 10, 2021.
6. "Hardware/Starlet". Wiibrew. Archived from the original on 16 May 2020. Retrieved 14 June 2020.
7. bushing (10 April 2008). "Wii System Software: a guided tour". HackMii — Notes from inside your Wii. Archived from the original on 20 September 2019. Retrieved 21 June 2020.
8. "IOS". Wiibrew. Archived from the original on 3 March 2020. Retrieved 21 June 2020.
9. "Hardware/AES Engine". Wiibrew. Archived from the original on 14 June 2020. Retrieved 14 June 2020.
10. "Hardware/SHA-1 Engine". Wiibrew. Archived from the original on 14 June 2020. Retrieved 14 June 2020.