RNG Brute Force Testing Script - Damage

-- RNG Brute Force Script
-- Author: Omnigamer
-- Instructions:
--
-- Fill in the information below according to what you want to test.
-- At the very minimum, you need an address for the RNG and a condition that you want to check.
-- In an emulator, start the script 2 frames before the RNG is checked and the condition you're watching changes.
-- Adapt the condition and tracking according to what you are trying to find out.
-- You will also potentially need to change the RNG function to suit the target game.

-- Addresses
RNG_ADDR = 0x00052C;
COND_ADDR = 0x000046;

-- Control values; number of frames to advance and how many times to test
NUM_FRAMES = 1;
NUM_ITER = 1000;

-- Sets the RNG to val; assumes a 16-bit RNG
function set_RNG(val)
    mainmemory.write_u16_le(RNG_ADDR,val);
end

-- Function that checks whether the condition and reports whatever information
-- you are trying to track from it.
function check_cond()

    cond = mainmemory.read_u16_le(COND_ADDR);

    myVal = hex2dec(cond);


    -- Logs the min, max, and average damage.
    if(myVal> maxVal) then
        maxVal = myVal;
    elseif(myVal<minVal) then
        minVal = myVal;
    end

    mySum = mySum + myVal;

end

-- Function that converts a hex listing of a base 10 value (damage) back to base 10.
function hex2dec(val)

    nibble1 = bit.band(val,0x000F);
    nibble2 = bit.band(bit.rshift(val,4),0x000F);
    nibble3 = bit.band(bit.rshift(val,8),0x000F);
    nibble4 = bit.band(bit.rshift(val,12),0x000F);

    return nibble1+nibble2*10+nibble3*100+nibble4*1000;

end

-- Advances the set number of frames. May need to be done when the RNG value is used
-- but the testable action is some number of frames away. Defaults to 1.
function advance_frames(val)
    for i=0,val,1 do
        emu.frameadvance();
    end
end

-- Sets up the save states
savestate.save("test_state");
savestate.load("test_state");

emu.limitframerate(false);

-- Initialize some variables
mycount = 0;
maxVal = 0;
minVal = 999;
mySum = 0;

-- Main testing loop
for i=0,NUM_ITER,1 do
    -- Grab a random value to set the RNG to; adjust size as necessary
    myrand = math.random(0,0xFFFF);
    set_RNG(myrand);

    -- Report various things that you're looking for on-screen
    gui.drawText(30,30,string.format("ITER:   %d",i));
    gui.drawText(30,45,string.format("MAX:    %d",maxVal));
    gui.drawText(30,60,string.format("MIN:    %d",minVal))
    gui.drawText(30,75,string.format("AVG:    %.2f",(mySum/i)));


    advance_frames(NUM_FRAMES);
    check_cond();
    savestate.load("test_state");
    final = i;
end

emu.limitframerate(true);

-- After the processing is done, just leave the information on-screen
while true do
        gui.drawText(30,30,string.format("ITER:   %d",final));
        gui.drawText(30,45,string.format("MAX:    %d",maxVal));
        gui.drawText(30,60,string.format("MIN:    %d",minVal))
        gui.drawText(30,75,string.format("AVG:    %.2f",(mySum/final)));

    emu.frameadvance();
end