Instead of only putting the image's code at 0x88300000, the ME now runs
it to where a PSP's ME is after boot: idle in its main loop's halt,
waiting for commands. As me_wrapper's boot (6.61, sceMeCore_driver
5dff5c50 and 0x1c30) and its ME stub leave things: the code at
0x88300000, the image's second stream still compressed after it, the
boot page's parameters (0x70C, 0x710 the CPU clock in MHz, 0x714), and
the ME at 0x88300000 with a0 at the second stream, which the code
decompresses into eDRAM itself. The stub's part (KL4E, caches) is done
here, since it runs main CPU kernel routines.
On a PSP the firmware has long since booted when a game starts, so it
runs to its idle halt the first time the ME runs, outside emulated time
(the JIT can't run earlier, at kernel init). About 80ms of startup in a
Debug build.
The compressed copy and the starting stack go below our idle threads'
stacks at the top of kernel memory, where a PSP has them higher up.
The firmware also needs:
- the ME to ignore the low two bits of jr/jalr targets: its command
table keeps flags there (interpreter, and the IR, for the ME only)
- source 5 of the ME's interrupt controller, the codec hardware it
starts and waits for in halt during init, which isn't emulated, so it
finishes at once
- sysreg 0x54 and 0x5C kept
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
