Hardware/Starlet: Difference between revisions
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The [[Hollywood]] includes an ARM9 core, nicknamed the Starlet. This is a very interesting piece of hardware, as it basically does everything that makes a Wii different from a | 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 96KB 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!'' | ''Note: this page is incomplete. Please expand it as you see fit!'' | ||
== | == Specs == | ||
[ | * NEC ARM926EJ-S SoC. See also [https://www.techinsights.com/products/nec-c10046f5-211-pn2-circuit-analysis-report ChipWorks]. | ||
* Big endian for compatibility with the Broadway | |||
* ARM and thumb instruction set | |||
* Clocked at 243MHz (Hollywood clock) | |||
== | == Exceptions == | ||
Exception vectors are located at <code>ffff0000</code>. Each exception is given 4 bytes, and usually branches elsewhere. | |||
{| class="wikitable" | |||
! Index | |||
! [[mini]] name | |||
! Description | |||
|- | |||
| 0 | |||
| v_reset | |||
| Hardware reset. Typically the entrypoint for official software. | |||
|- | |||
| 1 | |||
| v_undf | |||
| Undefined instruction, used as handler for [[IOS/Syscalls|IOS syscalls]] | |||
|- | |||
| 2 | |||
| v_swi | |||
| SVC/SWI instruction, used for [[IOS/Syscalls#Syscalls_.28via_ARM_syscall_instruction.29|IOS SWI syscalls]] | |||
|- | |||
| 3 | |||
| v_instr_abrt | |||
| Instruction abort | |||
|- | |||
| 4 | |||
| v_data_abrt | |||
| Data abort | |||
|- | |||
| 5 | |||
| v_reserved | |||
| Reserved | |||
|- | |||
| 6 | |||
| v_irq | |||
| [[Hollywood/IRQs|IRQ]] | |||
|- | |||
| 7 | |||
| v_fiq | |||
| FIQ | |||
|} | |||
== Boot == | == Boot == | ||
{{Seealso|boot process}} | |||
Starlet is the first processor to run code in the Wii. | Starlet is the first processor to run code in the Wii. | ||
* Starlet boots from an internal Mask ROM, BOOT0 | *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 47 pages of flash) | ||
* | *[[boot1]] locates, loads, decrypts, verifies, and runs BOOT2 | ||
* | *[[boot2]] starts the IOS | ||
* | *[[IOS]] loads [[System Menu]] into memory and bootstraps the {{hw|Broadway}} using the [[Hardware/External_Interface#EXI_boot_vector|EXI boot vector]] | ||
== Links == | == Links == | ||
More information about the Starlet: | More information about the Starlet: | ||
* [http://infocenter.arm.com/help/topic/com.arm.doc.ddi0198d/DDI0198_926_TRM.pdf ARM926EJ-S Technical Reference Manual] - CPU, MMU, Cache specs and programmer's interface | |||
* [https://web.archive.org/web/20050308211243/http://www.arm.com:80/pdfs/DDI0222B_9EJS_r1p2.pdf ARM9EJ-S Technical Reference Manual] - CPU specs and programmer's interface | |||
* [https://web.archive.org/web/20081221072959/http://www.arm.com/miscPDFs/14128.pdf 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. | * [[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 | * [[ARM Binaries]] - the formats used for Starlet executable code | ||
* [[WAD Files]] are used for BOOT2 and the IOS | * [[WAD Files]] are used for BOOT2 and the IOS | ||
* [https://www.freepatentsonline.com/y2005/0132217.html Patent for Starlet and IOS] | |||
[[Category:Hardware]] |
Latest revision as of 08:13, 27 September 2022
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 96KB 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)
Exceptions
Exception vectors are located at ffff0000
. Each exception is given 4 bytes, and usually branches elsewhere.
Index | mini name | Description |
---|---|---|
0 | v_reset | Hardware reset. Typically the entrypoint for official software. |
1 | v_undf | Undefined instruction, used as handler for IOS syscalls |
2 | v_swi | SVC/SWI instruction, used for IOS SWI syscalls |
3 | v_instr_abrt | Instruction abort |
4 | v_data_abrt | Data abort |
5 | v_reserved | Reserved |
6 | v_irq | IRQ |
7 | v_fiq | FIQ |
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 47 pages of flash)
- boot1 locates, loads, decrypts, verifies, and runs BOOT2
- boot2 starts the IOS
- IOS loads System Menu into memory and bootstraps the Broadway using the EXI boot vector
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