Latest from the #psxdev IRC Channel on EFnet

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Revision 4 (11/DEC/2017).

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[2019-03-10 17:29:16] <Nextria> i can't seem to program the Arduino pro mini with Psnee, on a Nano it is working without a problem.
[2019-03-10 17:27:25] <Nextria> i am back
[2019-03-10 17:26:03] <zid`> wtf
[2019-03-10 17:25:27] <Nextria> brb
[2019-03-10 17:23:42] <Nextria> anyone here can help me with programming a Arduino pro mini on a Uno ?
[2019-03-10 17:20:06] <Nextria> good morning
[2019-03-10 05:56:30] <mistamont> wsups
[2019-03-06 16:42:10] <zid`> and having breakpoints set in the bios can cause my disk to fail to load, silently
[2019-03-06 16:41:07] <zid`> It thinks 27BDFFE8 is 'push ra, r16, wasted' instead of addiu sp, sp, -24
[2019-03-06 16:40:42] <zid`> another bug in no$, fun
[2019-03-06 13:01:48] <zid`> (and thankfully for x86, IDA can do an okay first pass of it for you)
[2019-03-06 13:01:27] <zid`> I always lift everything into C
[2019-03-06 13:01:13] <krom> m35: nice =D
[2019-03-06 13:00:58] <zid`> oh a person
[2019-03-06 13:00:41] <m35> Snapshot of my in-progress static code analysis https://imgur.com/a/BtgQXnu
[2019-03-06 13:00:20] <m35> At this point I can only see one option: recreate the logic in C, create some unit tests, and begin refactoring it until more patterns emerge. Anyone know of other tools or approaches to de-compile PS assembly?
[2019-03-06 13:00:00] <m35> The pSX debugger lets me step through the code and set breakpoints. This got me to the area of code I'm interested in. I've done the static code analysis, which exposed the inputs and outputs in RAM, how some of the data is passed around, some familiar bit manipulation, as well as identifying some of the loops involved. I've stepped through the code as well to see it in action. But this chunk of code does a whole lotta stuff that I can't make
[2019-03-06 13:00:00] <m35> sense of.
[2019-03-06 12:59:44] <m35> Hi all. I've been pretty successful at reverse-engineering PS games to understand bits of logic. But I've hit a wall on this one and wondered if there are RE strategies I'm overlooking.
[2019-03-06 05:27:00] <zid`> https://github.com/zid/psx/blob/chek/main.c source, https://drive.google.com/open?id=1bz-Dqb3tdPrZ8ZqXOPSzo0dgRRRzhtMY binary
[2019-03-06 05:17:47] <zid`> then faulting again, repeat
[2019-03-06 05:17:43] <zid`> It's calling "ero2" as though it were an address, probably just a corrupt stack
[2019-03-06 05:17:00] <zid`> looks like maybe an exception handler, which then calls a function pointer which makes no sense
[2019-03-06 05:16:46] <zid`> yea no luck, and hitting F7 after it does.. nothing just appears to be garbage
[2019-03-06 05:14:26] <zid`> I'll acknowlege all irqs and enable them all and see what happens
[2019-03-06 05:14:03] <zid`> oh right so it may just be stuck waiting for the cd, good idea
[2019-03-06 05:13:49] <chek> no but I suspect they need to be enabled for the cdrom
[2019-03-06 05:13:22] <zid`> I haven't previously enabled any, should I force them all off?
[2019-03-06 05:12:55] <chek> are IRQ's disabled
[2019-03-06 05:10:06] <zid`> (they both do infact, go to the same function in the bios, who knew)
[2019-03-06 05:09:55] <zid`> oh it's on B0/32 in that one, thing says they're the same, I wanted to try both :D
[2019-03-06 05:09:28] <zid`> https://cdn.discordapp.com/attachments/417023075348119556/552553205628796928/unknown.png
[2019-03-06 05:07:17] <zid`> yea it's currently that, I think I removed it to test, it's back now
[2019-03-06 05:07:05] <chek> so maybe you do need cdrom:
[2019-03-06 05:06:55] <chek> > The PSX supports only a current directory, but NOT a current device (ie. after chdir, the directory name may be ommited from filenames, but the device name must be still included in all filenames).
[2019-03-06 05:04:36] <chek> ok I guess that's not the problem I was thinking it could be
[2019-03-06 05:00:39] <zid`> but the mov r24,r2 never runs
[2019-03-06 05:00:33] <zid`> it assembles to mov r24, 1; mov r9, 0; mov r10, 0xA0; mov r4, sp; mov r5, r24; sub sp, 10h; call r10 (+nop); mov r24,r2; add sp, 10h
[2019-03-06 04:59:32] <zid`> so it should be good?
[2019-03-06 04:59:29] <zid`> after the jalr.. r4 = path, r5 = 1, r9 = 0, pc = A0
[2019-03-06 04:58:48] <zid`> I needed a notes
[2019-03-06 04:58:45] <zid`> hang On I am checking what's up :D
[2019-03-06 04:58:35] <chek> no I mean when you do "r" (path), "r" (mode) could it be choosing t1 or t2 for those
[2019-03-06 04:58:01] <zid`> so erm
[2019-03-06 04:57:55] <zid`> and function number in r9
[2019-03-06 04:57:39] <zid`> Parameters, Registers, Stack
[2019-03-06 04:57:39] <zid`> Argument(s) are passed in R4,R5,R6,R7,[SP+10h],[SP+14h],etc.
[2019-03-06 04:57:39] <zid`> Caution: When calling a sub-function with N parameters, the caller MUST always allocate N words on the stack
[2019-03-06 04:56:46] <chek> you can probably have the inputs go directly into a0 / a1 instead
[2019-03-06 04:56:12] <chek> any chance it's using t1 or t2 for the asm inputs
[2019-03-06 04:19:21] <zid`> so I ended up in the right piece of code at least
[2019-03-06 04:19:14] <zid`> I single stepped it a bit, it was reading the string, pruning leading spaces etc
[2019-03-06 04:18:51] <zid`> it just gets lost in the bios forever
[2019-03-06 04:18:48] <zid`> and it isnt' like, failing to open the file
[2019-03-06 04:18:41] <zid`> so I tried that too
[2019-03-06 04:18:37] <zid`> chdir is documented as in: A0 Pointer to new directory path (eg. "cdrom:\path")
[2019-03-06 04:18:19] <zid`> err \\ to get \
[2019-03-06 04:18:10] <zid`> oh yea I tried cdrom://zero2.bmp
[2019-03-06 04:17:37] <chek> like cdrom:zero2.bmp
[2019-03-06 04:17:26] <chek> do you need some kind of prefix
[2019-03-06 03:54:43] <zid`> https://cdn.discordapp.com/attachments/417023075348119556/552199627529781268/unknown.png plsfix
[2019-03-06 03:54:37] <zid`> pinchy: you can do it for me if you like :P
[2019-03-05 23:43:27] <pinchy> u can do eet
[2019-03-05 14:56:52] <zid`> can't for the life of me get FileOpen on the bios to work, sigh. Getting about ready to write my own filesystem parser using raw cd commands >_<
[2019-03-05 03:54:10] <Zerofool> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 03:44:52] <tromp28> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 03:11:37] <forgotten> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 03:07:54] <mun_> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:44:55] <FalkHe> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:44:38] <bathtub_s> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:19:59] <ilpianist> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:15:36] <gchristen> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:12:29] <plitter> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 02:07:21] <cyphix> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:54:59] <dexta26> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:52:52] <stoner19> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:51:07] <baker0052> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:47:23] <Guest1643> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:45:12] <connyosis> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:40:39] <bghost> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-05 01:00:26] <logicmoo> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 23:11:23] <tristanC> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 22:51:24] <AWizzArd> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 22:48:37] <s0_iggie> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 22:47:02] <decayofmi> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 22:34:17] <asilluron> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 22:31:54] <shookees> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 21:32:26] <xpander69> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 21:23:41] <kipras`aw> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 20:21:37] <asidorenk> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 20:05:13] <ML-feeds[> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 19:27:29] <IwandeRer> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 19:17:47] <SmileyKei> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 19:12:53] <cheshirca> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 18:26:45] <colescott> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 18:26:39] <arecaceae> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 18:06:42] <slacker_n> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 14:32:00] <modulitos> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 14:27:42] <diddledan> https://twitter.com/OneTrueKloeri/status/1101825947752427520
[2019-03-04 13:46:00] <feirlane> https://twitter.com/OneTrueKloeri/status/1101825947752427520

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