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06-02-2014, 10:08 PM
(This post was last modified: 06-02-2014, 10:11 PM by avok23.)
I was trying to find an efficient way to learn file formats from ps2 games together with manually deciphering the file format through Hex editor to atleast verify what is going on.
I tried using DVD reads together with debug info (EE Cache) but it did not bring the clarity i was hoping for. Not only was it dead slow I actually thought the debugger would dump out Sequences of instructions.
I am actually new to this. I only found out about MIPS last night and i have gotten all the information i could gather on it (15 hours of Videos and tutorials from sony and other colleges).
While i am glad i have the knowledge i am suddenly terrified i might be wasting my time. Staring at elf/slus/sles files in ps2dis is pretty terrifying. (Why is there no scroll bar?  )
I am on my 4th can of monster and i am still going to do this but if anyone one can save me from wasting my time i'll be eternaly grateful.
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I also have a strange question
Code: beq zero, zero, $00115570
why would you ever need to check if zero is zero? It throws me off.
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06-03-2014, 01:03 AM
(This post was last modified: 06-03-2014, 01:03 AM by Saiki.)
what if zero isn't zero? then there's a large error somewhere. it's always wise to check and make sure everything is what it should be
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Well, an identifier will always be equal to itself... the real question to the OP is: are you sure to be disassembling a code area instead a data area?
Imagination is where we are truly real
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06-03-2014, 01:45 AM
(This post was last modified: 06-03-2014, 01:46 AM by avok23.)
I am assuming the code area is always towards the bottom. The files are huge and i just figured out how to dump it to a text file.
This looks like code to me. but if there is a more sane way to differentiate please share
Code: kgm_map_anim: #
sw a0, $0058(sp) # 00110d40:afa40058
lw a1, $0050(sp) # 00110d44:8fa50050
__00110d48: #
blez a1, $001109a4 # 00110d48:18a0ff16 ^ __001109a4
daddu s0, a1, zero # 00110d4c:00a0802d
__00110d50: #
lw a0, $0048(sp) # 00110d50:8fa40048
addiu a2, zero, $0020 # 00110d54:24060020 a2=$00000020
lw a1, $005c(sp) # 00110d58:8fa5005c
lw v1, $0044(sp) # 00110d5c:8fa30044
jalr v1 # 00110d60:0060f809
addiu s0, s0, $ffff # 00110d64:2610ffff
lw a0, $0058(sp) # 00110d68:8fa40058
addu a0, a0, v0 # 00110d6c:00822021
bne s0, zero, $00110d50 # 00110d70:1600fff7 ^ __00110d50
sw a0, $0058(sp) # 00110d74:afa40058
beq zero, zero, $001110b4 # 00110d78:100000ce v __001110b4
lbu a1, $0000(s6) # 00110d7c:92c50000
__00110d80: #
andi v0, s5, $0004 # 00110d80:32a20004
beq v0, zero, $00110f64 # 00110d84:10400077 v __00110f64
addiu v0, zero, $0030 # 00110d88:24020030 v0=$00000030
bne a3, v0, $00110e48 # 00110d8c:14e2002e v __00110e48
lw a1, $0050(sp) # 00110d90:8fa50050
lw a1, $0054(sp) # 00110d94:8fa50054
beq a1, zero, $00110df4 # 00110d98:10a00016 v __00110df4
daddu s0, zero, zero # 00110d9c:0000802d
addiu s3, sp, $0020 # 00110da0:27b30020
sltu s4, s2, s1 # 00110da4:0251a02b
__00110da8: #
addu v0, s3, s0 # 00110da8:02701021
lw a0, $0048(sp) # 00110dac:8fa40048
lb a2, $0000(v0) # 00110db0:80460000
addiu s0, s0, $0001 # 00110db4:26100001 s0=$00000001
lw a1, $005c(sp) # 00110db8:8fa5005c
lw v1, $0044(sp) # 00110dbc:8fa30044
sq a3, $0060(sp) # 00110dc0:7fa70060
jalr v1 # 00110dc4:0060f809
sq t0, $0070(sp) # 00110dc8:7fa80070
lw a0, $0058(sp) # 00110dcc:8fa40058
lw a1, $0054(sp) # 00110dd0:8fa50054
addu a0, a0, v0 # 00110dd4:00822021
kgm_map_anim_ctrl: #
lq a3, $0060(sp) # 00110dd8:7ba70060
sw a0, $0058(sp) # 00110ddc:afa40058
slt v0, s0, a1 # 00110de0:0205102a
bne v0, zero, $00110da8 # 00110de4:1440fff0 ^ __00110da8
lq t0, $0070(sp) # 00110de8:7ba80070
beq zero, zero, $00110dfc # 00110dec:10000003 v __00110dfc
lw v0, $0050(sp) # 00110df0:8fa20050
__00110df4: #
sltu s4, s2, s1 # 00110df4:0251a02b
lw v0, $0050(sp) # 00110df8:8fa20050
__00110dfc: #
blez v0, $00110ef4 # 00110dfc:1840003d v __00110ef4
nop # 00110e00:00000000
daddu s0, v0, zero # 00110e04:0040802d
kgm_map_gnd: #
lw a0, $0048(sp) # 00110e08:8fa40048
daddu a2, a3, zero # 00110e0c:00e0302d
lw a1, $005c(sp) # 00110e10:8fa5005c
addiu s0, s0, $ffff # 00110e14:2610ffff
lw v1, $0044(sp) # 00110e18:8fa30044
sq a3, $0060(sp) # 00110e1c:7fa70060
jalr v1 # 00110e20:0060f809
sq t0, $0070(sp) # 00110e24:7fa80070
lw a0, $0058(sp) # 00110e28:8fa40058
lq a3, $0060(sp) # 00110e2c:7ba70060
addu a0, a0, v0 # 00110e30:00822021
lq t0, $0070(sp) # 00110e34:7ba80070
bne s0, zero, $00110e08 # 00110e38:1600fff3 ^ kgm_map_gnd
sw a0, $0058(sp) # 00110e3c:afa40058
beq zero, zero, $00110ef4 # 00110e40:1000002c v __00110ef4
nop # 00110e44:00000000
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06-03-2014, 02:05 AM
(This post was last modified: 06-03-2014, 02:13 AM by avok23.)
I should probably have a strategy.
I know the name of the object that contains all the data
Code: "DATA/FID.BIN": #
.byte $44 # 002b3f30 68 'D'
.byte $41 # 002b3f31 65 'A'
.byte $54 # 002b3f32 84 'T'
.byte $41 # 002b3f33 65 'A'
.byte $2f # 002b3f34 47 '/'
.byte $46 # 002b3f35 70 'F'
.byte $49 # 002b3f36 73 'I'
.byte $44 # 002b3f37 68 'D'
.byte $2e # 002b3f38 46 '.'
.byte $42 # 002b3f39 66 'B'
.byte $49 # 002b3f3a 73 'I'
.byte $4e # 002b3f3b 78 'N'
nop # 002b3f3c:00000000
luckily ps2dis generates some comments
so i try to find every instance of $3f30 like:
Code: addiu a1, a1, $3f30 # 00193b9c:24a53f30 a1="DATA/FID.BIN"
Then i check the neighbouring instructions to see what it is doing and if i can understand it.
i have also checked for labels with the word "load" in them.
I had started by looking for something like
Code: li $v0, 13 # system call for open file
la $a0, fin # input file name
...
....
syscall # open a file
I wish i could just dump it all in Spim and step through it
I am new to this and this is probably a dumb question is there a way to simulate the extra EE instruction sets that pc programs like Spim are missing even if it has tto be ridiculously slow.
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06-03-2014, 08:38 PM
(This post was last modified: 06-03-2014, 10:12 PM by gregory.)
The open is not done on the EE side. The command is send to IOP with a RPC mecanism. There is a sif-rpc-tracer branch not perfect but it might be easier to see the RPC transaction (they used sif0/sif1 dma). By the way, even on IOP it doesn't use any syscall.
On the file format, there are 2 possibilities.
1/ file format is self-contained, all informations to decode the file is contained on the file. There is somethings like an header that describe the content of the file and where to get the data.
2/ file format is raw binary. Game got some pointer with the location of the data. Either there is would some value in the data segment. Either it is directly hardcoded in mips like
Code: lui r1 upper
addiu r1 lower
addu r2 r1 # to compute relative address based on the loaded part.
Edit: enable bios log in iop (last menu)
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06-04-2014, 02:56 AM
(This post was last modified: 06-04-2014, 05:40 AM by avok23.)
Thank you very much sir. I dont know why i never thought of IO.
But i wont even pretend to understand that. "Bios Log in IOP"? Never seen such an option
The "IOP Console" option doesnt show much of anything.
Some files have headers others dont. Japanese also slightly throws me off at times. ( Why would there ever be an integer value larger than the file size in a file? With the data making no sense as an int uint, float or short?)
Never heard of RPC
So I guess I am meant to look into "IOPRP300.IMG" or "SIO2MAN.IRX"? (I thought these were just like general libraries with instructions that can be called from the main SLPM/slus/sles etc)
PS if my above guess is true how would i recognize such a function call?
I guess i still know nothing Off to study some more
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06-04-2014, 04:55 AM
(This post was last modified: 06-04-2014, 08:38 AM by gregory.)
Just in case any fellow noobs are interested in this journey I will post all the crap i found along the way
Quote:*** Removed copyrighted materials ***
http://www.philvaz.com/games/PS2IOP.pdf <-- This is the IOP stuff i am supposed to read i guess.
Out of curiousity i wonder if anyone one here did a Comp Sci course.
We did alot of c, c++ and java and only 1 week of assembly in 4 years.
Not sure if you realize this, or not, but all the PDF's appear to be blank. Unless those are empty placeholders you're going to fill...
I kinda got bored of emulation, but I do more lurking than anything else now. I'll keep an eye on this thread  .
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