I started reverse engineering Where in the World is Carmen Sandiego (Enhanced DOS edition) and I'm trying to find how it generates its random seeds so I search on int 1a and the first thing I find is it's doing TANDY SOUNDS?

Funny fact: I was trying to get an online assembler to spit out the machine code for "int 1a" but couldn't get it to, so I just went "fuck it, I can probably just do that in my head!"

Turns out I can. My brain is weird.

Here's something I didn't know existed until just now: Where in the World is Carmen Sandiego checks your name against the list dossier list and rejects you if you use any of those names.

PRONOUNS DETECTED: THIS GAME IS WOKE

sadly they don't have they/them on here. What about the non-binary criminals, huh?

stretch goal: hack in at least on enby criminal with appropriate pronouns. maybe I'll just put myself in the game as one of the criminals you can apprehend

I faked this screenshot but this is what I mean

I think I might be able to do the hack I want by changing one byte.

I'm trying to change it so it has "daily challenges", and I think I can fix that by just switching a INT 1A from subfunction 00 to 04, making it seed the random function with the date instead of the ticks-since-midnight

eh, I used 5 bytes. I don't need to impress anyone

NORMAL CODE

random(*(byte *)*(undefined2 *)
(*(int *)(*(int *)0x39a6 * 0xe + local_c * 2 + 0x1d02) * 2 +
*(int *)(local_c * 2 + 0x24b)) - 1);

I found another set of pronouns!

I haven't figured out how this game stores gender, but I'm gonna go out on a limb and say it's like this:
male: 0
female: 4

why? because they have strings like:
char* HE="He\0\0She\0"
char* HIS="His\0Hers\0";
char* HIM="Him\0Her\0";

so they can do like:

printf("Follow %s to %s lair, and capture %s alive!", badguy->name, HIS+badguy->gender, HIM+badguy->gender);

I like how the game only asks your name, not your gender.
Player's don't have genders. Only thieves have genders.

It's a prequel to Disco Elysium, and your gender is set to COP

why does ghidra's "search by instruction pattern" default to BINARY?
what kind of a freak remembers the machine code for INT 21 on x86 in BINARY?
it's CD21h, not 1100110100100001!

what are you, some kind of nerd?

I love reversing a string and it's:

void printString(char* str, int length);

and I go look what calls it, reverse that function, and it's:

void printStringSimple(char *str){
printString(str, strlen(str));
}

it's like "aww, did someone have second thoughts about making PRINT always take a length, and got tired of having to manually calculate lengths so you just wrapped it?

and your compiler didn't inline SHIT?

oh those poor people of Bamako! Someone stole their.

okay so when you start a game (well, technically when you restart), the game rolls 3 dice:
0-31: where the shit was stolen from
0-2: which item it is from that location
0-8: whodunnit