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AGI Syntax Help / AGI Random Number Generator

« on: November 19, 2017, 12:38:22 AM »

Hi,

I'm trying to crack the RNG behind the slot machine in SQ1 to help someone with a TAS of the game.  We've found the code for NAGI's random function:

Code: [Select]

       u16 diff;
       u16 min;
       u16 max;
       
       min =  *(c++);
       max = *(c++);
       diff = max - min +1;
       state.var[*(c++)] = (agi_rand() % diff) + min;
       return c;

where agi_rand() calls:

Code: [Select]

   if (agi_rand_seed == 0)
        {
              //printf("Creating new randomised seed...\n");
              /* ah = 0; int(1Ah); */     // number of ticks since midnight
#ifndef RAD_LINUX
              _ftime (&t);         // time since 1970 but that's ok
#else
              ftime(&t);
#endif
              //printf("time = %ld seconds %ld milliseconds\n", t.time, t.millitm );
              agi_rand_seed = t.time * TANDY_CLOCK_PER_SEC;
              agi_rand_seed += (u16) ((double)t.millitm  / 1000 * TANDY_CLOCK_PER_SEC);
              //printf("seed = 0x%04X\n\n", agi_rand_seed);
       }

        agi_rand_seed = 0x7C4D * agi_rand_seed + 1;
       r = agi_rand_seed ^ (agi_rand_seed>>8);
        return( r );

and this seems to be correct some of the time, but not always.  JAGI seems to have a completely different function.

Does anyone know how I can find out the random logic used in the actual AGI interpreter?