Main Processor

Main SoC
See Kermit.

Cortex A9 MPcore
The custom SoC includes the ARM Cortex-A9 MPCore as its CPU, mounting four little-endian ARM Cortex-A9 processor cores, which is common in modern high performance embedded devices like cell phones and tablets. The PSVita cores have a MIDR value of, meaning it is Cortex-A9 r2p10. Indeed there are usage of undocumented CP15 registers.

Implemented Coprocessor registers
Each core includes the following features:
 * L1 Instruction Cache of 32 KiB and Data Cache of 32 KiB
 * Media Processing Engine (MPE) that can execute Advanced SIMD instructions (NEONv1) and Vector Floating-Point v3 instructions (VFPv3)

In addition, there is a L2 cache of 2 MiB shared by all cores, while precisely speaking, it's external to the ARM processor core.

Documentation
A lot of useful information is available about ARM (Advanced RISC Machines) on the internet including ARM Ltd. official site.


 * Refer to the following document for the instruction set, memory model and programmers' model: ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition.


 * The ARM Cortex-A9 Technical Reference Manual gives a good overview of the specific processor features and is a good reference for what ARMv7 implementation specific features are enabled.


 * Another manual that's important is the ARM Cortex-A9 MPCore Technical Reference Manual which is specific to the multi-core system the Vita uses. The main information of use are descriptors for the private memory region defined with the  signal. This is mapped to physical address.


 * Some reserved registers are documented in the Cortex-A9 Errata Notices (r0/r1/r2/r3/r4)

(corresponding to the chip revision supposed to be included in DevKit):
 * Cortex-A9 Technical Reference Manual

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0388f/DDI0388F_cortex_a9_r2p2_trm.pdf

(NEON: Advanced SIMD instructions)
 * Cortex-A9 NEON Media Processing Engine Technical Reference Manual

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0409f/DDI0409F_cortex_a9_neon_mpe_r2p2_trm.pdf


 * Cortex-A9 NEON MPE > VFPv3 architecture hardware support

http://infocenter.arm.com/help/topic/com.arm.doc.ddi0409f/CHDEEJDB.html

(The above reference destination has been confirmed as of June 26, 2014. Note that pages may have been subsequently moved or its contents modified.)

Interrupt Controller
As part of the Cortex A9 MPcore, the Vita also implements the Generic Interrupt Controller Architecture. More information on interrupts can be found here.

L2 Cache
PSVita uses the PL310 r3p1-50rel0 L2 cache (Cache ID Register = 0x410000C7) that is mapped to paddr.