 |
forums.ps2dev.org
Homebrew PS2, PSP & PS3 Development Discussions
|
| View previous topic :: View next topic |
| Author |
Message |
m0skit0
Joined: 02 Jun 2009
Posts: 226
|
 Posted: Tue Jun 16, 2009 10:11 pm Post subject: A bit of help with assembler in H.BIN |
 |
|
Hi guys!
I'm trying to make my own h.bin for the MaTiaZ TIFF loader, but I can't get it to succeed writing some data to a file. I've done the code in assembler, so here's how I do it:
| Code: | # a0 = SCEPAF_MODULE
# pc = 0x08800000
# SCEPAF_MODULE ($s3)
addu $s3,$zero,$a0
# sceIoOpen()
lui $t0,0x15
ori $t0,$t0,0xee70
addu $t0,$t0,$s3
# file path
lui $a0,0x880
ori $a0,$a0,0x200
# flags write & create
addiu $a1,$zero,0x602
jalr $ra,$t0
# mode 0777
addiu $a2,$zero,0x1ff
# file descriptor ($s2)
or $s2,$zero,$v0
# sceIoWrite()
lui $s1,0x880
ori $s1,$s1,0x200
lui $t0,0x15
ori $t0,$t0,0xee40
addu $t0,$t0,$s3
# file descriptor
addu $a0,$zero,$s2
# size
addiu $a2,$zero,0x10
jalr $ra,$t0
# pointer to data
addu $a1,$zero,$s1
# sceIoClose()
lui $t0, 0x15
ori $t0,$t0,0xee60
jalr $ra,$t0
# file descriptor
addu $a0,$zero,$s2
nop
# Loop forever
lui $t0,0x880
ori $t0,$t0,0x60
jr $t0
nop |
With the string ms0:/regdump at address 0x08800200.
Doesn't work, well at least not the write procedure, or maybe the close, because it creates the file but it is just empty.
Anyone sees anything wrong in here? Thanks in advance!
_________________
| The Incredible Bill Gates wrote: | | The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers. |
|
|
| Back to top |
|
 |
Dariusc123456
Joined: 12 Aug 2008
Posts: 394
|
| Posted: Wed Jun 17, 2009 12:34 am Post subject: |
|
|
Lol, why dont you make an sdk so you dont have to use assembly? In the readme file of the hello world exploit, it given instructions on how to make the sdk.
| Quote: | You can then trick out function imports, like for example sceDisplayWaitVblankStart:
sceDisplayWaitVblankStart = (void*)(paf_addr+0x15F068);
|
EDIT:
The zero variable ONLY contain zeros, and nothing else, so that could be the problem. I havent look completely at your code.
_________________
PSHN - Playstation Hacking Network
PSX/PS1 - HACK - Game Shark
PS2 - HACK - Swap
PSP - HACK - Pandora
PS3 - ? |
|
| Back to top |
|
|
m0skit0
Joined: 02 Jun 2009
Posts: 226
|
| Posted: Wed Jun 17, 2009 1:27 am Post subject: |
|
|
| Dariusc123456 wrote: | | why dont you make an sdk so you dont have to use assembly? |
Just want to write it in assembly. Each one does the job as he pleases, right? ;)
| Dariusc123456 wrote: | | You can then trick out function imports |
That's exactly what I'm doing. As I said, the sceIoOpen() function works, as the file is created, but nothing happens next (besides freeze and power off, of course)
| Dariusc123456 wrote: | | The zero variable ONLY contain zeros |
I guess you mean the $zero register. I know that, which is pretty obvious anyway, but I don't understand how this can be the problem. I think I use it in the right way. This is not my first assembly program, anyway ;)
Thanks anyway
_________________
| The Incredible Bill Gates wrote: | | The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers. |
|
|
| Back to top |
|
|
Dariusc123456
Joined: 12 Aug 2008
Posts: 394
|
| Posted: Wed Jun 17, 2009 7:20 am Post subject: |
|
|
I dont use MIPS Assembly as much anymore, but when I use it, its only when reverse enginnering programs. But when I do want to, I write in C, then use the psp-gcc and convert it to assembly and work from there.
But when I have time, ill look over your code, and debug it to see if there any problems when outputing the data. Does it fill the file with the size of the data being outputed? It so after the sceIoOpen, you should use the beq, so it its dont equal to NULL, or ZERO, then jump to the next address to finish the output of the data.
Let me guess, you have a PSP 3000 or a PSP Slim with TA-88v3?
_________________
PSHN - Playstation Hacking Network
PSX/PS1 - HACK - Game Shark
PS2 - HACK - Swap
PSP - HACK - Pandora
PS3 - ? |
|
| Back to top |
|
|
jbit
Site Admin
Joined: 28 May 2005
Posts: 293
Location: København, Danmark
|
| Posted: Wed Jun 17, 2009 10:14 am Post subject: |
|
|
Are you assembling with .set noreorder? If you're not then you can't use the branch delay slot like you are..
For example with this code:
| Code: | lui $a0,0x880
ori $a0,$a0,0x200
addiu $a1,$zero,0x602
jalr $ra,$t0
addiu $a2,$zero,0x1ff |
With reordering (default) a2 will not get set before the jump. (For open this is fine, but your write looks like it'll lose its data pointer, which might be causing your bug?) This is what the assembler generates:
| Code: | 0: 3c040880 lui a0,0x880
4: 34840200 ori a0,a0,0x200
8: 0100f809 jalr t0
c: 24050602 li a1,1538
10: 240601ff li a2,511 |
With ".set noreorder" the assembler generates this:
| Code: | 0: 3c040880 lui a0,0x880
4: 34840200 ori a0,a0,0x200
8: 24050602 li a1,1538
c: 0100f809 jalr t0
10: 240601ff li a2,511 |
(edit: also Dariusc123456, I really wish you wouldn't comment on threads when you clearly have no idea) |
|
| Back to top |
|
|
Dariusc123456
Joined: 12 Aug 2008
Posts: 394
|
| Posted: Wed Jun 17, 2009 11:17 am Post subject: |
|
|
jbit, I am very busy with alot of things. I can focus on two things at one time. Sorry if it sound like im confuse, but I am serious
_________________
PSHN - Playstation Hacking Network
PSX/PS1 - HACK - Game Shark
PS2 - HACK - Swap
PSP - HACK - Pandora
PS3 - ? |
|
| Back to top |
|
|
m0skit0
Joined: 02 Jun 2009
Posts: 226
|
| Posted: Wed Jun 17, 2009 6:52 pm Post subject: |
|
|
| Quote: | | Does it fill the file with the size of the data being outputed? It so after the sceIoOpen, you should use the beq, so it its dont equal to NULL, or ZERO, then jump to the next address to finish the output of the data. |
I still don't understand what you're trying to tell me, sorry... If you can explain a little more...
Also, thanks for the reply jbit, but here's how I get it assembled myself:
| Code: | 0000001c: 3c080015 lui $t0,0x15
00000020: 3508ee70 ori $t0,$t0,0xee70
00000024: 01134021 addu $t0,$t0,$s3
00000028: 3c040880 lui $a0,0x880
0000002c: 34840200 ori $a0,$a0,0x200
00000030: 24050602 addiu $a1,$zero,1538=0x0602
00000034: 0100f809 jalr $ra,$t0
00000038: 240601ff addiu $a2,$zero,511=0x01ff |
My assembler really uses addiu and don't replace it with li, and also it doesn't change the order. So $a1 & $a2 get loaded before the jump actually takes place, right?
I'm used to use (:P) add, or and and to load values in registers. You think this is correct? Should I use li instead? I really see no difference if the register gets loaded properly.
_________________
| The Incredible Bill Gates wrote: | | The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers. |
|
|
| Back to top |
|
|
jbit
Site Admin
Joined: 28 May 2005
Posts: 293
Location: København, Danmark
|
| Posted: Wed Jun 17, 2009 9:46 pm Post subject: |
|
|
| m0skit0 wrote: | | My assembler really uses addiu and don't replace it with li, and also it doesn't change the order. So $a1 & $a2 get loaded before the jump actually takes place, right? |
Ah, okay, GNU AS reordering things by default has screwed me up a few times, but if you're using a different assembler then I guess it's not a problem. (and yes, with that disasm a1 and a2 both get loaded before the jump is executed)
| m0skit0 wrote: | | I'm used to use (:P) add, or and and to load values in registers. You think this is correct? Should I use li instead? I really see no difference if the register gets loaded properly. |
Ah, sorry for the confusion, I used your assembly (and assembled with gnu as) and disassembled with objdump... objdump will show instructions as pseudo instructions if it can. li/la/etc are pseudo, so they're not real instructions but a macro in the assembler, the actual instructions would be the same as the input. I'm so used to just converting them in my head when I see them that I didn't notice, hehe :) http://en.wikipedia.org/wiki/MIPS_architecture#Pseudo_instructions
Anyway other than that the asm itself looks fine to me, assuming your indexes into the jump table are correct. I'm not really a PSP guy so I'm not sure about other details. |
|
| Back to top |
|
|
m0skit0
Joined: 02 Jun 2009
Posts: 226
|
| Posted: Thu Jun 18, 2009 12:33 am Post subject: |
|
|
| jbit wrote: | | Anyway other than that the asm itself looks fine to me, assuming your indexes into the jump table are correct. I'm not really a PSP guy so I'm not sure about other details |
Well I'm pretty sure the jumps are correct because I used the same that MaTiaZ's TIFF loader and ChickHEN use, and reviewed them a few times. And I also don't see why this is not working, because I already tried this code (or something very similar) as a function inside the ChickHEN and it worked...
This is annoying...
Thank you very much for your time!
_________________
| The Incredible Bill Gates wrote: | | The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers. |
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
