Add documentation for piracy checks

src/game/chr/chr.c

@@ -3963,8 +3963,7 @@ void chrUncloak(struct chrdata *chr, bool value)
 			}
 
 			if (checksum != CHECKSUM_PLACEHOLDER) {
-				extern volatile u32 _antipiracyUncloakWriteAddress[];
-				_antipiracyUncloakWriteAddress[-2] = 0;
+				((u32 *)&func0002a324)[-2] = 0;
 			}
 		}
 #endif

src/game/core.c

@@ -1836,9 +1836,9 @@ glabel coreGetSlowMotionType
 //u32 coreGetSlowMotionType(void)
 //{
 //#if PIRACYCHECKS
-//	u32 addr = sub54321(0xb000de8d);
+//	u32 addr = sub54321(0xb0000a5c + 54321);
 //	u32 actual;
-//	u32 expected = sub54321(0x1741d42a);
+//	u32 expected = sub54321(0x1740fff9);
 //	osPiReadIo(addr, &actual);
 //
 //	if (actual != expected) {

src/game/propobj.c

@@ -44680,11 +44680,11 @@ void func0f08e2ac(struct doorobj *door)
 	}
 
 #if PIRACYCHECKS
-	if (osCicId != decodeXorAaaaaaaa(0xaaaabd73)) {
+	if (osCicId != decodeXorAaaaaaaa(6105 ^ 0xaaaaaaaa)) {
 		u32 *ptr = (u32 *)func0f08f968;
-		ptr[0] = 0x00001025;
-		ptr[1] = 0x03e00008;
-		ptr[2] = 0x00000000;
+		ptr[0] = 0x00001025; // li v0, 0
+		ptr[1] = 0x03e00008; // jr ra
+		ptr[2] = 0x00000000; // nop
 	}
 #endif
 }

src/include/lib/lib_233c0.h

@@ -79,6 +79,7 @@ f32 func000296a0(struct collisionthing *arg0, struct coord *pos, struct tilethin
 bool func00029ffc(struct coord *pos, f32 width, f32 foreheadheight, f32 inversefeettoeyesheight, s16 *rooms, u32 arg5, struct coord *laddernormal);
 u32 func0002a13c(void);
 f32 cdFindGroundY(struct coord *pos, f32 width, s16 *rooms, u16 *floorcol, u8 *floortype, u16 *floorflags, s16 *floorroom, s32 *inlift, struct prop **lift);
+f32 func0002a324(void);
 f32 cdFindGroundYSimple(struct coord *pos, f32 width, s16 *rooms, u16 *floorcol, u8 *floortype);
 f32 func0002a36c(struct coord *coord, s16 *rooms, u16 *floorcol, s32 arg3);
 s32 func0002a400(struct coord *pos, s16 *rooms);

src/lib/lib_233c0.c

@@ -7211,6 +7211,13 @@ f32 cdFindGroundY(struct coord *pos, f32 width, s16 *rooms, u16 *floorcol,
 	return ground;
 }
 
+/**
+ * This function must come immediately after cdFindGroundY.
+ *
+ * A piracy check looks for this function, then backtracks two instructions to
+ * nop the jr ra at the end of cdFindGroundY, causing it to flow into this
+ * function and return 0.
+ */
 f32 func0002a324(void)
 {
 	return 0;