papermario/src/general_heap_create_obfuscated.c
Ethan Roseman 625d7874c5
Shiftability, naming of things (#930)
* Naming, shiftability fixes, etc

* follows_vram fixes

* more goods

* tweesterz

* agh

* warnings

* agh
2023-02-02 20:23:17 +09:00

55 lines
1.7 KiB
C

#include "common.h"
#include "nu/nusys.h"
#include "ld_addrs.h"
#include "mips.h"
extern u8 obfuscated_general_heap_create[];
#ifdef SHIFT
void general_heap_create_obfuscated(void) {
general_heap_create();
}
#else
void general_heap_create_obfuscated(void) {
s32(*readFunc)(OSPiHandle*, u32, u32*) = osEPiReadIo;
s32 seed = 0x3C016C07 + 0xFEFEFEF;
HeapNode*(*general_heap_create)(void) = (HeapNode* (*)(void)) obfuscated_general_heap_create; // general_heap_create - 0xFEFEFEF
u32 hash = 0;
u32 thisInsn;
u32* it;
u32 prevInsn;
readFunc(nuPiCartHandle, 0xB0000574, &thisInsn);
seed -= thisInsn; // thisInsn = 0x3C016C07 here, so seed becomes 0xFEFEFEF
prevInsn = 0;
for (it = (u32*) load_engine_data_obfuscated_ROM_START; it < (u32*) load_engine_data_obfuscated_ROM_END; it++) {
readFunc(nuPiCartHandle, (u32) it, &thisInsn);
hash += LOWER(thisInsn) + UPPER(thisInsn);
if (OPCODE(prevInsn) == LUI && (OPCODE(thisInsn) == ADDIU || OPCODE(thisInsn) == LW)) {
if (GET_RS(thisInsn) == GET_RT(prevInsn) && GET_RS(thisInsn) == GET_RT(thisInsn)) {
hash -= LOWER(thisInsn);
hash -= LOWER(prevInsn);
}
}
if (OPCODE(thisInsn) == JAL) {
hash -= LOWER(thisInsn) + (UPPER(thisInsn) & 0xFC00);
}
prevInsn = thisInsn;
}
// 0x2499BF - hash == 0, so we add back 0xFEFEFEF (seed) and we end up with the address of general_heap_create!
general_heap_create += seed + 0x2499BF - hash;
// If the function's address is 0x8XXXXXXX
if (((u32)general_heap_create >> 0x1C) == 8) {
// Call the function that ends up being general_heap_create
general_heap_create();
}
}
#endif