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#1
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I want to increase the dmg of Atma Weapon, and planning to change the divided damage to 48 or 32, however I just can't understand the bold text below. Its not using hex 40 but something else. 

Atma Weapon damage modification

C2/0E39: 08           PHP
C2/0E3A: DA           PHX 
C2/0E3B: 5A           PHY 
C2/0E3C: 9B           TXY            (Y points to attacker)
C2/0E3D: B9 F5 3B     LDA $3BF5,Y    (HP / 256)
C2/0E40: 1A           INC 
C2/0E41: EB           XBA 
C2/0E42: B9 18 3B     LDA $3B18,Y    (Level)
C2/0E45: 20 81 47     JSR $4781      (Level * ((HP / 256) + 1))
C2/0E48: BE 1D 3C     LDX $3C1D,Y    (Max HP / 256)
C2/0E4B: E8           INX 
C2/0E4C: 20 92 47     JSR $4792      ((Level * ((HP / 256) + 1)) / ((Max HP / 256) + 1))
C2/0E4F: 85 E8        STA $E8        (save modifier quotient)
C2/0E51: C2 20        REP #$20
C2/0E53: A5 F0        LDA $F0        (load damage so far)
C2/0E55: 20 B7 47     JSR $47B7      (24-bit $E8 = modifier in 8-bit $E8 * 16-bit damage)
C2/0E58: A9 05 00     LDA #$0005
C2/0E5B: 20 D1 0D     JSR $0DD1      (Divide 24-bit Damage in $E8 by 64. [note that
                                      calculation operates on 4 bytes])

C2/0E5E: 1A           INC            (+1)
C2/0E5F: 85 F0        STA $F0        (save final damage)
                                     (note that we're assuming damage fit into 16 bits,
                                      which is true outside of hacks that give Atma
                                      Weapon 2-hand or elemental properties.)
C2/0E61: C9 F5 01     CMP #$01F5
C2/0E64: 90 0D        BCC $0E73      (branch if < 501)
C2/0E66: A2 5B        LDX #$5B       (put index for alternate, bigger weapon
                                      graphic, into X)
C2/0E68: C9 E9 03     CMP #$03E9
C2/0E6B: 90 01        BCC $0E6E      (branch if < 1001)
C2/0E6D: E8           INX            (make graphic bigger yet)
C2/0E6E: 86 B7        STX $B7        (save graphic index)
C2/0E70: 20 BB 35     JSR $35BB      (Update a previous entry in ($76) animation buffer
                                      with data in $B4 - $B7)  (Changes Atma Weapon length)
C2/0E73: 7A           PLY 
C2/0E74: FA           PLX 
C2/0E75: 28           PLP 
C2/0E76: 60           RTS
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#2
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Code:
C2/0E58: A9 05 00     LDA #$0005
C2/0E5B: 20 D1 0D     JSR $0DD1      (Divide 24-bit Damage in $E8 by 64. [note that
                                     calculation operates on 4 bytes])
According to Assassin's disassembly, entering that subroutine at $0DD1 takes the number and divides it by 2^(A+1).
Because A is set to 5 right before the subroutine, the result is 2^6, or division by 64.

You could change LDA #$0005 to #$0004 to make the division 32 instead (doubling the damage), but getting a divisor that isn't a power of two won't be possible with an in-line change.
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[-] The following 1 user says Thank You to C-Dude for this post:
  • doofenH (06-17-2020)



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