Editing Talk:PSP Emulation

= Notes =

* No keys available in emu, so everything is loaded decrypted from ISO
* BOOT.BIN is the loaded executable from ISO
* 3 psp remasters (1 is below 4.55, 2 others above 4.55 but below 5.05)
* size of patapon is 574MB, size of locoroco 2 is 3.3GB


* Crashing near sceGeListEnQueue means low vram??

= Patches =

<source lang="lua">
local gpr		= require( "ax-gpr-alias" ) -- you can access Allegrex GPR by alias (gpr.a0 / gpr["a0"])
local pad		= require( "pad" ) -- pad state
local emuObj		= getEmuObject() -- emulator
local axObj		= getAXObject() -- allegrex

-- Fixup additional songs path
local addOnPathHook = function()
	local pathPtr = axObj.GetGpr(gpr.a2)
	axObj.WriteMemStrZ(pathPtr, "ao0:/MUSIC/") -- reroute to add-on directory
end

axObj.AddHook(0x88c022c, 0x24c66de0, addOnPathHook)
...
</source>

reroutes sceIoOpen "ms0:/PSP/SAVEDATA/UCUS98702MUSIC/" to "ao0:/MUSIC/"

axObj.AddHook(0x8800000 (base) + offset in psp boot.bin, original bytes little endian, hook_function)

=CLI settings available in Echodrome emu=
Not all, just interesting ones. 
<br>Settings without variable are just on/off /true/false/ 0/1.
*'''--forcenobilinear''' Possibly required for Persona 3, and few more

*'''--antialias'''
**msaa4x
**ssaa4x

*'''--texcachemode''' for issues with texture cache (modes lower than full possibly read some textures directly without cache).
**drawboundsloco
**patchworkheroes
**locoroco2
**rondo (Castlevania: The Dracula X Chronicles?)
**full

*'''--smoothlevel''' (unknown max level)
*'''--anisolevel''' (unknown max level)

*'''--present''' set when frame is presented. Sync issues, flickering screen, tearing, input lag, etc.
**vblankstart
**setframebuf
**drawsync

*'''--vramcopyback''' for games that download data from GPU to Allegrex
*'''--gputhread''' possibly move GPU emulation to another thread, speedhack but can decrease compatibility.

*'''--xobuttonmode''' self explaining
**oenter
**ocancel

'''Additionally emulator check for title IDs:
'''
*NPUG80325 GOW Chains of Olympus
*NPEG00023 GOW Chains of Olympus
*NPHG00027 GOW Chains of Olympus
*NPUG80508 GOW Ghost of Sparta
*UCUS98617 Gangs of London
*UCES00113 Gangs of London
And do something when ID match, for now is unknown what exactly.

== Registers ==

With recent findings from user Scalerize we have now regs base. So we can see mapping from Get/Set registers lua functions. ;)
* GPR registers start at base + 0x288, since emu code set ra in jal opcode, we ca see that ra is at base + 304. So base for GPR regs is 0x200414D24 - (31 * 4). Which give us 0x200414CA8 for $zero reg, 0x200414CAC for $at, rest is already documented. 
* '''Base is 0x200414A20''' ($zero reg - 0x288)
* Hi/Lo regs are located at base + 0x308/0x30C (0x200414D28 Lo/ 0x200414D2C Hi), based on GetHi/GetLo lua functions.
* FPR regs start a base + 0x32C (0x200414D4C), from $f00 up to $f31, 4 bytes (wasn't psp fpu able to work with doubles? but emu for sure use 32 bit regs). Based on Get/Set Fpr lua code.
* PC is at base + 0x314, already documented.
* First five VFPU extra registers ([http://hitmen.c02.at/files/yapspd/psp_doc/chap4.html#sec4.5.2 info]) are mapped to base + 0x5C0.
* VFPU 135 reg read just return 0x7772CEAB, it's not mapped anywhere.
* VFPU regs 136 to 139 read base + 0x558, and 140 to 143 read base + 0x564 (which are probably mapped to something important, maybe VFPU 128 bit regs.)
* Todo: VFPU registers, but i need to reverse instruction decoder to do that.
--[[User:Kozarovv|Kozarovv]] ([[User talk:Kozarovv|talk]]) 08:02, 22 June 2023 (CEST)



<br> Are C000 and E000 and R000 registers? --[[User:Scalerize|Scalerize]] ([[User talk:Scalerize|talk]]) 20:53, 22 June 2023 (CEST)