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Author Topic: Modifying speed of players in NFL Blitz 2000  (Read 986 times)

starfishmaster

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Modifying speed of players in NFL Blitz 2000
« on: January 12, 2016, 06:56:05 pm »
I have recently been trying to figure out how to modify a player speed in NFL Blitz. I have successfully been able to find the address that writes to the player speed, however I don't know how to "hard-code" the change to make it permenant. Here's what I know:

Using the memory debugger in nemu64, I can trip the command that the address writes to:

802F7FD4 SWC1 F0,0x0014(S0).

just above this line is:
802F7FD0 MUL.S F0,F20,F0
followed by the line just above that being
802F7FCC NOP

So I changed the NOP command to be the same as MUL.S F0,F20,F0. Doing so made the character move at twice the speed - however I would rather him be slightly slower. I assume that the MUL.S F0,F20,F0 command multiplies the F20 and F0 and stores in F0, hence when I have two of these commands back to back (when I change the NOP), it makes it twice as fast. So my question is essentially: How can I hard code a multiplication command to the variable going to the SWC1 command, F0?

I have never used any tools to try and actually "hard code" the rom. If anyone can follow this and give me some advice it would be appreciated greatly!