Hardware/Starlet

The Hollywood includes an ARM9 core to handle I/O and security, nicknamed the Starlet by fail0verflow, but internally known as the IOP, short for Input/Output Processor. This is a very interesting piece of hardware, as it basically does everything that makes a Wii different from a GameCube.

The Starlet contains an internal 24MB SRAM; if IOS needs more memory, it can lock part of MEM2 to prevent Broadway access.

Note: this page is incomplete. Please expand it as you see fit!

Specs

• NEC ARM926EJ-S SoC. See also ChipWorks.
• Big endian for compatibility with the Broadway
• ARM and thumb instruction set
• Clocked at 243MHz (Hollywood clock)

Boot

See also: boot process

Starlet is the first processor to run code in the Wii.

• Starlet boots from an internal Mask ROM, BOOT0 (about 1300 bytes of code out of 4K possible)
• boot0 decrypts, verifies, and runs the first few blocks of NAND, BOOT1 (up to the first 48 pages of flash)
• boot1 locates, loads, decrypts, verifies, and runs BOOT2
• boot2 bootstrap then loads the embedded ELF file
• boot2 starts the IOS
• IOS loads code into the EXI buffer and bootstraps the Broadway

Links

More information about the Starlet:

• ARM926EJ-S Technical Reference Manual - CPU, MMU, Cache specs and programmer's interface
• ARM9EJ-S Technical Reference Manual - CPU specs and programmer's interface
• ARM Architecture Reference Manual - Documentation about the ARMv5 architecture.
• IOS - the OS that runs on the Starlet and handles calls from the Broadway during game execution and while in the system menu.
• ARM Binaries - the formats used for Starlet executable code
• WAD Files are used for BOOT2 and the IOS
• Patent for Starlet and IOS