Posted: 5/31/2007 8:51 PM
Post subject: What's a save state?
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unrivaledXspeed
Joined: 5/30/2007
Posts: 4
I know by asking this question it makes me probably sound like a noob but I really don't know what a Save State is or how to use them...It's confusing me...can anyone give me answers or tell me how to use them... And if this was already posted...then sry for not looking around more... Thanks for any help!
Posted: 5/31/2007 8:52 PM
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moozooh
Senior Moderator
Joined: 8/4/2005
Posts: 5777
Location: Away
top of the page wrote:
If you have a question, please read the FAQ first to see if your question has already been answered.
Just do it.
Warp wrote:
Edit: I think I understand now: It's my avatar, isn't it? It makes me look angry.
Posted: 5/31/2007 8:53 PM
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Zurreco
Former player
Joined: 8/1/2004
Posts: 2687
Location: Seattle, WA
http://tasvideos.org/Glossary.html#savestate_ Depending on what emulator you're using, there are different ways to save and load savestates. Don't forget that the FAQ is your friend.
hi nitrodon streamline: cyn-chine
Posted: 5/31/2007 8:54 PM
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Atma
Former player
Joined: 9/1/2005
Posts: 803
A miserable little pile of secrets.
Posted: 5/31/2007 10:51 PM
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RT-55J
Player (150)
Joined: 11/27/2004
Posts: 688
Location: WA State, USA
'Savestate' is just a colloquiallism for 'saved state'. State in this context refers to the 'condition' of the emulated console. When you load a state you should be at the exact same moment as when you saved it.
Nach wrote:
I also used to wake up every morning, open my curtains, and see the twin towers. And then one day, wasn't able to anymore, I'll never forget that.
Posted: 5/31/2007 10:53 PM
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Phil
Active player (411)
Joined: 3/16/2004
Posts: 2623
Location: America, Québec
RT-55J wrote:
'When you load a state you should be at the exact same moment as when you saved it.
Yes normally, "you should" but it's not always true.
Posted: 5/31/2007 11:14 PM
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Mitjitsu
He/Him
Banned User
Joined: 4/24/2006
Posts: 2997
TAS of 2007 N64 TAS of 2007
I'm actually curious as to whats exactly stored within each savestate, since surely you would need to store the characters postion motion, acceleration, room state, and possibly many other things.
Posted: 5/31/2007 11:18 PM
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RT-55J
Player (150)
Joined: 11/27/2004
Posts: 688
Location: WA State, USA
A saved state is just a dump of the console's RAM.
Nach wrote:
I also used to wake up every morning, open my curtains, and see the twin towers. And then one day, wasn't able to anymore, I'll never forget that.
Posted: 5/31/2007 11:24 PM
(Edited: 6/1/2007 12:32 PM)
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DeHackEd
Emulator Coder, Site Developer, Former player
Joined: 11/6/2004
Posts: 833
It also includes all the memory for other hardware, like the sound, graphics, etc. Also, the CPU's registers, mode, etc. Also, in movies there's movie information stored for rerecording. Basically any piece of hardware that needs to do work over an extended period needs its state saved. SRAM is often tossed in as well. Etc. Etc.
Posted: 6/1/2007 1:42 AM
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Cardboard
Skilled player (1605)
Joined: 6/11/2006
Posts: 818
Location: Arboga, Sweden
NES TAS of 2008 Rookie of 2007 GBx TASer of 2007
Atma wrote:
A miserable little pile of secrets.
No, that's a man.
Warp wrote:
omg lol this is so fake!!!1 the nes cant produce music like this!
Posted: 6/1/2007 3:38 AM
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Rick
Former player
Joined: 6/25/2004
Posts: 607
Location: Maine
Dracula is Cardboard! ...But that doesn't make any sense. o_o
http://wiki.rustedlogic.net/The_Cutting_Room_Floor The Cutting Room Floor wiki.
Posted: 6/3/2007 7:25 PM
(Edited: 6/3/2007 9:17 PM)
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creaothceann
He/Him
Editor
Joined: 4/7/2005
Posts: 1874
Location: Germany
AKA wrote:
I'm actually curious as to whats exactly stored within each savestate, since surely you would need to store the characters postion motion, acceleration, room state, and possibly many other things.
Savestates are not game-specific (means: they store everything and don't care about character positions etc). In the FAQ there's a list of file extensions (FMV, VMV, FCM etc). The linked pages show what each movie file type contains - sometimes also a savestate. The source of the emulator should show what is saved in one. Btw. RHDN has the old ZST format.
Posted: 6/3/2007 9:10 PM
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nitsuja
Emulator Coder, Skilled player (1310)
Joined: 12/21/2004
Posts: 2687
Computer TASer of 2011 TAS of 2011 First edition TAS of 2011 Computer TAS of 2011 Sega TAS of 2010 Sega TAS of 2008 Sega TAS of 2007 Glitchy TAS of 2007
For most practical purposes they are game-specific, in that you usually can't expect to load a savestate in a different game and continue playing in any meaningful way, and the state of the ROM is arguably part of the emulated system you're intending to take a snapshot of even if isn't directly stored in the snapshot. Also, cartridge-based games often include their own additional hardware (especially NES and some SNES games), which must be represented in the savestates.
Posted: 6/4/2007 7:30 AM
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AnS
Emulator Coder, Experienced player (728)
Joined: 2/23/2006
Posts: 682
BTW, is there any kind of documentation on FCS format somewhere in the Internet? Same question with VMV and Snes9x savestates.
Posted: 6/4/2007 7:32 AM
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Bisqwit
Editor, Active player (297)
Joined: 3/8/2004
Posts: 7469
Location: Arzareth
AnS wrote:
BTW, is there any kind of documentation on FCS format somewhere in the Internet? Same question with VMV and Snes9x savestates.
fceu/src/state.c virtuanes/something/equivalent.c snes9x/snes9x/savestate.cpp I.e. besides the source code, highly unlikely.
Posted: 6/4/2007 10:24 PM
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creaothceann
He/Him
Editor
Joined: 4/7/2005
Posts: 1874
Location: Germany
-> vSNES source/uS9X.pas Files are usually compressed via gzip, can be extracted with WinRAR etc. The gzip library can also read transparently from uncompressed files. 
file header:
 - Signature (8 chars)
 - Colon     (1 char )
 - Version   (4 chars)
 - Delimiter (1 char )
Files are organized in blocks which come after the header. 
block structure:
 - Name   (3 chars     )
 - Colon1 (1 char      )
 - Size   (6 chars     )
 - Colon2 (1 char      )
 - Data   ([Size] bytes)
Required block order: 
"NAM" (cartridge name)
"CPU" (CPU status)
"REG" (CPU registers)
"PPU" (PPU status, basically registers $2100+ with some modifications)
"DMA" (DMA registers)
"VRA" (VRAM)
"RAM" (WRAM)
"SRA" (SRAM, always $20000 bytes)
"FIL" (FillRAM, 32 KB storing the last values of the registers $xx:0000..$xx:7FFF, regardless if mapped or not)
"APU" (APU status, optional)
"ARE" (only if "APU" is present: APU registers)
"ARA" (only if "APU" is present: APU RAM)
"SOU" (only if "APU" is present: other sound data)
"SA1" (SA-1 status, optional)
"SAR" (only if "SA1" is present: SA-1 registers)
"SP7" (SPC7110 status)
"RTC" (S7RTC status)