Past Gen RNG Research

08084AB0 0400     lsl     r0,r0,10h     ; this is at 0x080B49F2 in Emerald (U), 0x0808196C in R/S (J), 0x080B414A E (J), 0x08084FEC R/S (FR), 0x080B4A06 Emerald (FR)
08084AB2 0C00     lsr     r0,r0,10h
08084AB4 2831     cmp     r0,31h        ; see post #749
08084AB6 D907     bls     8084AC8h      
08084AB8 E03E     b       8084B38h      ; if the calculated slot is not feebas's ([0;49]), skip the feebas tile determination routine
08084ABE 0202     lsl     r2,r0,8h                                
08084AC0 DC00     bgt     8084AC4h       ; DIFFERENT ON R/S JAP and FR                         
08084AC2 0839     lsr     r1,r7,20h                               
08084AC4 2001     mov     r0,1h         ; feebas = true                           
08084AC6 E038     b       8084B3Ah
                                
08084AC8 481F     ldr     r0,=2025734h  ; r0 = 0x03005D8C (pointer) in Emerald (U)                          
08084ACA 4B20     ldr     r3,=2DD6h     ; 0x2E6A in Emerald.                          
08084ACC 18C0     add     r0,r0,r3      ; 0x0202850A in R/S (U and FR), 0x02028896 E (U), 0x0202826A R/S (J), 0x02028542 E (J), 0x02028882 E (FR)                      
08084ACE 8800     ldrh    r0,[r0]		; load feebas seed on r0                                 
08084AD0 F000F850 bl      8084B74h      

	08084B74 0400     lsl     r0,r0,10h                               
	08084B76 0C00     lsr     r0,r0,10h                               
	08084B78 4901     ldr     r1,=202FF80h ; store r0 in 0x202FF80 (R/S U)                            
	08084B7A 6008     str     r0,[r1]  
	08084B7C 4770     bx      r14  
                     
08084AD4 2500     mov     r5,0h         ; r5 (loop counter) = 0;                          
08084AD6 4E1E     ldr     r6,=1BFh      ; r6 = 0x1BF                          
08084AD8 F000F83C bl      8084B54h 

	08084B54 4A04     ldr     r2,=202FF80h                             
	08084B56 6811     ldr     r1,[r2]       ; load full seed                          
	08084B58 4804     ldr     r0,=41C64E6Dh                           
	08084B5A 4348     mul     r0,r1                                   
	08084B5C 4904     ldr     r1,=3039h     ; 0x3039 [B]NOT[/B] 0x6073 !                          
	08084B5E 1840     add     r0,r0,r1                                
	08084B60 6010     str     r0,[r2]		; store full (u32) result of (0x41C64E6D * seed + 0x3039) at 0x202FF80                        
	08084B62 0C00     lsr     r0,r0,10h     ; r0 (output) >>= 16                           
	08084B64 4770     bx      r14
                               
08084ADC 0069     lsl     r1,r5,1h		; r1 = 0                                
08084ADE 466A     mov     r2,r13        ; r2 = sp                          
08084AE0 1854     add     r4,r2,r1      ; r4 = r2 + 0                          
08084AE2 0400     lsl     r0,r0,10h                               
08084AE4 0C00     lsr     r0,r0,10h                               
08084AE6 1C31     mov     r1,r6         ; r1 = 0x1BF                          
08084AE8 F15CFA0E bl      81E0F08h      ; r0 = r0 mod r1                          
08084AEC 8020     strh    r0,[r4]       ; store r0 ( tile ) on the stack                          
08084AEE 0400     lsl     r0,r0,10h                               
08084AF0 2800     cmp     r0,0h         ; if r0 is null                          
08084AF2 D100     bne     8084AF6h                 
08084AF4 8026     strh    r6,[r4]       ; store 0x1BF instead                          
08084AF6 8820     ldrh    r0,[r4]       ; load calculated feebas tile                          
08084AF8 3801     sub     r0,1h                                   
08084AFA 0400     lsl     r0,r0,10h                               
08084AFC 0C00     lsr     r0,r0,10h                               
08084AFE 2802     cmp     r0,2h         ; if tile is either 1,2, or 3, (unacessible) don't increment the loop, so generate new tiles number to be checked with                          
08084B00 D902     bls     8084B08h                                
08084B02 1C68     add     r0,r5,1                                 
08084B04 0600     lsl     r0,r0,18h                               
08084B06 0E05     lsr     r5,r0,18h     ; increment r5 by 1.                          
08084B08 2D06     cmp     r5,6h         ; if r5 < 6;                          
08084B0A D1E5     bne     8084AD8h      ; calculate another feebas tile to check with.                          
08084B0C 464B     mov     r3,r9                                 
08084B0E 2100     mov     r1,0h                                   
08084B10 5E58     ldsh    r0,[r3,r1]    ; r0 = rod->map.x                          
08084B12 4642     mov     r2,r8                                   
08084B14 2300     mov     r3,0h                                   
08084B16 5ED1     ldsh    r1,[r2,r3]    ; r1 = rod->map.y                          
08084B18 1C3A     mov     r2,r7                                   
08084B1A F7FFFF33 bl      8084984h      ; from (fishing) coordinates return current tile in r0            
              
08084B1E 0400     lsl     r0,r0,10h                               
08084B20 0C01     lsr     r1,r0,10h                               
08084B22 2500     mov     r5,0h                                   
08084B24 0068     lsl     r0,r5,1h                                
08084B26 4468     add     r0,r13        ; r0 = sp                           
08084B28 8800     ldrh    r0,[r0]                                 
08084B2A 4281     cmp     r1,r0         ; is the current tile a feebas tile ?  SET A BREAKPOINT THERE TO SEE THE CURRENT TILE AND ALL YOUR FEEBAS TILES.
										; in emerald, this opcode is located at 0x080B4A6C (U)                        
08084B2C D0CA     beq     8084AC4h		; if so, feebas = true                          
08084B2E 1C68     add     r0,r5,1       ; increment r5                          
08084B30 0600     lsl     r0,r0,18h                               
08084B32 0E05     lsr     r5,r0,18h                               
08084B34 2D05     cmp     r5,5h                                   
08084B36 D9F5     bls     8084B24h      ; if r5 <= 5 increment                        
08084B38 2000     mov     r0,0h         ; The current tile is not a feebas tile (feebas = false)                         
08084B3A B004     add     sp,10h                                  
08084B3C BC18     pop     r3,r4                                   
08084B3E 4698     mov     r8,r3                                   
08084B40 46A1     mov     r9,r4                                   
08084B42 BCF0     pop     r4-r7                                   
08084B44 BC02     pop     r1                                      
08084B46 4708     bx      r1

inline u32 RNG(u32 seed){
    return (0x41C64E6D * seed + 0x3039)
}

bool isFeebasTile(u16 feebasSeed, u16 currentTile){
    u32 fullRNGResult = (u32) feebasSeed, i = 0;
    u16 tile = 0;
    while(i <=5){ // Not exactly done this way, but equivalent
        fullRNGResult = RNG(fullRNGResult);
        tile = ((fullRNGResult >> 16) & 0xFFFF % 0x1BF);
        if (tile >= 4) i++;
        if (tile == currentTile) return true;
    }
    return false;
}

021F5138 B5F8     push    r3-r7,r14		                               
021F513A 1C0C     mov     r4,r1         ; r4 = current slathered tree                          
021F513C 0E02     lsr     r2,r0,18h		; r0 = SIDTID. For example r0 = 0x78CA5E96 when TID = 0x5E96 and SID = 0x78CA                      
021F513E A900     add     r1,sp,0h      ; r1 = sp                          
021F5140 700A     strb    r2,[r1]       ; set (SID >> 16) & 0xFF on the stack                          
021F5142 0C02     lsr     r2,r0,10h                               
021F5144 704A     strb    r2,[r1,1h]    ; set SID & 0xFF on the stack (+1)                          
021F5146 0A02     lsr     r2,r0,8h                                
021F5148 708A     strb    r2,[r1,2h]    ; set (TID >> 16) & 0xFF on the stack (+2)                          
021F514A 70C8     strb    r0,[r1,3h]    ; set TID & 0xFF on the stack (+3)
                          
021F514C 7808     ldrb    r0,[r1]       ; for each byte of the SID then the TID (byte #0)                         
021F514E 2115     mov     r1,15h                                  
021F5150 F6F6ED96 blx     20EBC80h		                               
021F5154 A800     add     r0,sp,0h                                
021F5156 7001     strb    r1,[r0]       ; store : byte mod 0x15 (=21). It corresponds to a tree number.                       
021F5158 7840     ldrb    r0,[r0,1h]    ; same order than precedently (byte #1)                         
021F515A 2115     mov     r1,15h                                  
021F515C F6F6ED90 blx     20EBC80h                                
021F5160 A800     add     r0,sp,0h                                
021F5162 7041     strb    r1,[r0,1h]                              
021F5164 7880     ldrb    r0,[r0,2h]    ; byte #2                          
021F5166 2115     mov     r1,15h                                  
021F5168 F6F6ED8A blx     20EBC80h                                
021F516C A800     add     r0,sp,0h                                
021F516E 7081     strb    r1,[r0,2h]                              
021F5170 78C0     ldrb    r0,[r0,3h]    ; byte #3                          
021F5172 2115     mov     r1,15h                                  
021F5174 F6F6ED84 blx     20EBC80h                                
021F5178 A800     add     r0,sp,0h                                
021F517A 70C1     strb    r1,[r0,3h]    
                          
021F517C 2000     mov     r0,0h         ; r0 = 0                          
021F517E 2301     mov     r3,1h         ; r3 = 1                          
021F5180 A900     add     r1,sp,0h      ; r1 = sp                          
021F5182 1C02     mov     r2,r0         ; r2 = 0                          
021F5184 1C15     mov     r5,r2         ; r5 = 0                          
021F5186 2B00     cmp     r3,0h         ; if r3 <= 0, r3++                           
021F5188 D90E     bls     21F51A8h                                
021F518A 5D4F     ldrb    r7,[r1,r5]                              
021F518C 5CCE     ldrb    r6,[r1,r3]    ; load two tree IDs                          
021F518E 42B7     cmp     r7,r6         ; if a same tree is chosen two times                         
021F5190 D105     bne     21F519Eh                                
021F5192 1C76     add     r6,r6,1       ; increment the second one                          
021F5194 54CE     strb    r6,[r1,r3]    ; store it                          
021F5196 5CCE     ldrb    r6,[r1,r3]    ; reload it                          
021F5198 2E15     cmp     r6,15h        ; if the chosen tree, r6, has an ID >= 21 (tree #21 doesn't exist)                          
021F519A D300     bcc     21F519Eh                                
021F519C 54C8     strb    r0,[r1,r3]    ; store 0 instead                          
021F519E 1C6D     add     r5,r5,1       ; r5++                          
021F51A0 062D     lsl     r5,r5,18h                               
021F51A2 0E2D     lsr     r5,r5,18h                               
021F51A4 429D     cmp     r5,r3         ; if r5 >= r3                          
021F51A6 D3F0     bcc     21F518Ah                                
021F51A8 1C5B     add     r3,r3,1       ; r3 ++                           
021F51AA 061B     lsl     r3,r3,18h                               
021F51AC 0E1B     lsr     r3,r3,18h                               
021F51AE 2B04     cmp     r3,4h         ; (if r3 >= 4, stop comparing trees)                          
021F51B0 D3E8     bcc     21F5184h      ; r5 = 0
										; r5 will take the following values : 0 0 1 0 1 2
										; r3 will take the following ones   : 1 2 2 3 3 3                          
021F51B2 2200     mov     r2,0h         ; r2 = 0                          
021F51B4 A900     add     r1,sp,0h      ; r1 = sp                          
021F51B6 5C88     ldrb    r0,[r1,r2]    ; load each tree ID                          
021F51B8 4284     cmp     r4,r0         ; is the tree being slathered a Munchlax one ?                          
021F51BA D101     bne     21F51C0h      ; if not ...                          
021F51BC 2001     mov     r0,1h         ; if the tree being slathered is a Munchlax tree, stop comparing, and return 1                          
021F51BE BDF8     pop     r3-r7,r15                               
021F51C0 1C50     add     r0,r2,1                                 
021F51C2 0600     lsl     r0,r0,18h                               
021F51C4 0E02     lsr     r2,r0,18h     ; ... increment r2                           
021F51C6 2A04     cmp     r2,4h         ; if r2 >= 4 stop comparing                          
021F51C8 D3F5     bcc     21F51B6h                                
021F51CA 2000     mov     r0,0h         ; and return 0                          
021F51CC BDF8     pop     r3-r7,r15

bool isMunchlaxTree(u8 currentTree, u16 TID, u16 SID) //Not done this way, but equivalent      
        u8 trees[4];
	for(u8 num = 0;num < 2; num++){
		trees[num]= ((sid >> ((1-num) * 8)) & 0xFF) % 0x15;
		trees[num+2]= ( (tid >> ( (1-num) * 8)) & 0xFF) % 0x15; 
	}
	u8 i = 0, j = 1, k = 0;
	while(j < 4){
		if(trees[i] == trees[j])
			if(++trees[j] == 21) trees[j] = 0;
		if(++i == j){
			i = 0;
			j++;
		}
	}
        while(k < 4){
                if(currentTree == trees[k]) return true;
                k++;
        }
        return false;
}

Set 1 = a & b
4467412A4B4F0374
4467412AC22843FD
Set 2 = a & b (XOR'd)
4467412A18D16D07 <- seed, when rolled back matches the IVs obtained
Set 3 = a (XOR'd) & b
C467412A18D16D07
Set 4 = a (XOR'd) & b (XOR'd)
C467412A4B4F0374
C467412AC22843FD

For genderless Pokémon:
0 Initial
1 PID
5 Nature
No other modifications.

For all-male Pokémon such as Tyrogue:
0 Initial
1 PID
2 PID lower byte ((u32 * 0xF6 >> 32) + 8)
6 Nature

For all-female Pokémon such as Kangaskhan:
0 Initial
1 PID
2 PID lower byte ((u32 * 0x8 >> 32) + 1)
6 Nature

For all other males:
0 Initial
1 PID
2 PID lower byte ((u32 * (0xFE - gender threshold) >> 32) + gender threshold
6 Nature

For all other females:
0 Initial
1 PID
2 PID lower byte ((u32 * (gender threshold - 1) >> 32) + 1
6 Nature

18825	5:13.75    72F9	 [color="RoyalBlue"]B[/color] /  [color="RoyalBlue"]A[/color] / [u]31[/u] / [u]31[/u] / [u]31[/u] /  [color="RoyalBlue"]B[/color]
Note: Split Spread

23746	06:35.8    F0DB	 [color="RoyalBlue"]A[/color] / [u]31[/u] / [u]31[/u] / [u]31[/u] /  [color="RoyalBlue"]B[/color] /  [color="RoyalBlue"]A[/color]
Note: Alternate Spread

[s]Cute Charm		66.7% chance to encounter opposite gender[/s] - done 100%!
Vital Spirit		50% chance for Higher Level Pokemon to be summoned.
Intimidate/Keen Eye	decreases the chance of encountering a lower-level wild Pokémon by 50%. 
Magnet Pull		50%+ Chance for Steel Type
Static			50%+ Chance for Electric Type