Editing PS2 Emulation

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= Description =
= Description =


The PlayStation 2 emulation on the PlayStation 4 is handled with little difference to the PlayStation 3. Some issues on PS3's PS2 emulator were left unfixed on the PlayStation 4. Consequently, the PS4 inherited some of PS3's emulation glitches, and even introduced new ones. The new issues came as a result of PS4's weakness with emulation, which likely resulted in the trade of accuracy for performance.
<pre>PlayStation 2 emulation on the PlayStation 4 is handled with little difference to the PlayStation 3.
Some issues on PS3's PS2 emulator were left unfixed on the PlayStation 4. Consequently, the PS4 inherited some of PS3's emulation glitches, while introducing new ones.
The new issues came as a result of PS4's weakness with emulation, which likely resulted in the trade of accuracy for performance.


Each PS2onPS4 package file (.pkg) includes the PS2 emulator itself. The PS4 does not have a native built-in emulator in its System Software, but it does have a few PS2 emulator specific features, like the usermode functions sceLncUtilIsPs2Emu, sceShellCoreUtilGetImposeMenuFlagForPs2Emu, sceSystemServiceAddLocalProcessForPs2Emu, and sceSystemServiceShowImposeMenuForPs2Emu.
Each PS2ONPS4 package file (.pkg) includes the emulator itself. The ps4 does not have a native built-in emulator in its firmware, but it does a few PS2 emulator specific features, like the functions sceLncUtilIsPs2Emu, sceShellCoreUtilGetImposeMenuFlagForPs2Emu, sceSystemServiceAddLocalProcessForPs2Emu, and sceSystemServiceShowImposeMenuForPs2Emu.


The PS2 emulators are programmed to be accurate for the games they were designed to emulate. In turn, this makes accurate emulation challenging, as emulators include per-title patches and different default settings. The PlayStation 2 hardware is a complex system to emulate; any small change in configuration can make or break a game. Currently, the most commonly used emulator is "Jakv2" from Jak games, as it is the most compatible one out there. When game crashes are concerned in an emulated PS2 game, then the Resident Evil Code: Veronica X's emulator is typically used, whereas for VU accuracy it is Rogue Galaxy's.
Emulators are programmed to be accurate for the games they were designed to emulate. In turn, this makes accurate emulation challenging, as emulators include per title patches and different default settings. The Playstation 2 hardware is a complex system to emulate; any small change in configuration can make or break a game.
Currently the most commonly used emulator is Jakv2 as it is the most compatible one out there. When game crashes are concerned, RECVX is typically used, whereas for VU accuracy it is roguev1.


The PS2 BIOS is included in the game's pkg file. It is the same PS2 BIOS as used in the ps2_netemu in PS3 Operating System. The lack of encryption mechanism for PS2 game disc image files is also huge. This time, it is a plain ISO file, but the emulator still supports LIMG sector that allows the usage of non-2048 sector size discs. Moreover, memory cards are also unencrypted, but the emulator checks the CRC of some of the regions to ensure that the memory card was not modified. The PS2 emulator on PS4 also supports LUA scripting by a "Lua Bridge", which is a powerful interface that may prove exceptionally handy in fixing games.
The PS2 BIOS is included in the game's pkg, the same one used on the ps2_netemu. The lack of encryption mechanism for PS2 game disc image file is also important. This time it is a plain ISO file, but the emulator still supports LIMG sector that allows the usage of non-2048 sector size discs. Moreover, memory cards are also decrypted, but the emulator checks the CRC of some of the regions to ensure that the memory card was not modified. This PS2 Emulator also supports LUA scripting by "Lua Bridge", which is a powerful interface that may prove exceptionally handy in fixing games.


This is first time that Sony has ever cared about floats in its emulators. Compared to the PS3 CPU, x86-64 is doing a worse job in mimicking FPU and VU floats calculation behavior. This is resolved by clamping, accurate math used per memory offset, and/or converting floats to double precision. The emulator uses OpenCL for GS, and likely other components as well.
This is first time that Sony has ever cared about floats in its emulators. Compared to the PS3 CPU, x86-64 is doing a worse job in mimicking FPU and VU floats calculation behavior. This is resolved by clamping, accurate math used per memory offset, and/or converting floats to double precision. The emulator uses openCL for GS, and likely other components as well.</pre>


= Emulator Configuration =
= Emulator Configuration =
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